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5' cap
a methylated guanine nucleotide added to the 5' end
of eukaryotic mRNA
...
The A band includes
regions of thick and thin filament overlap, as well as
a region of thick filament only
...
The A band does not shorten
during muscle contraction
...
(usually
because Na+ channel closed whle K+ efflux)
Accessory glands
The three glands in the male reproductive system
that reproduce semen: the seminal vesicles, the
prostate, and the
Accessory organs
(1) In the GI tract, organs that play a role in
digestion but not directly part of the alimentary
canal
...
1
Acetylcholine (Ach)
The neurotransmitter used throughout the
parasympathetic nervous system as well as the
neuromuscular junction
...
Acetyl-CoA
The first substrate in teh Krebs cycle, produced
primarily from the oxidation of pyruvate by the
pyruvate dehydrogenase complex, however
acetyl-CoA is also produced during fatty acid
oxidation and protein catabolism
...
Acid
hydrolases are found within the lysosomes of cells
...
For example, in the
pancreas, acinar cells secrete digestive enzyme; in
the salivary glands, acinar cells secrete saliva
...
In skeletal and cardiac muscle,
actin polymerizes (along with other proteins) to form
the thin filaments
...
Action potential
A localized change in a neruon's or musce cell's
membrane potential that can propogate itself away
from its point of origin
...
Activation energy (Ea)
The amount of energy required to produce the
transition state of a chemical reaction
...
Enzymes (and other
catalysts) increase reaction rates by reducing
activation energy
...
3
Active transport
The movement of molecules through the plasma
membrane against their concentration gradients
...
An example is the Na+/K+
ATPase in the plasma membrane of all cells
...
Adenine is apurine; it pairs with thymine (in DNA)
and with uracil (in RNA)
Adenohypophis
anterior pituitary gland
Adipocyte
fat cell
Adrenal medulla
The inner region of the adrenal gland
...
These hormones augment and prolon the effects of
sympathetic stimulation in the body
...
Adrenocoricotropic hormone
(ACTH)
A trop hormone produced by the anterior pituitary
gand that targets the adrenal cortex, stimulating it to
relase corisol and aldosterone
...
Afferent neuron
A neuron that arries information (action potentials)
to the central nervous system; a sensory neuron
...
Albumin
helps to mantain blood osmotic pressure (oncotic
pressure)
5
Aldosterone
The principal mineralocorticoid secreted by teh
adrenal cortex
...
(this causes
ADH to be secreted & increased water comes out,
increasing blood pressure indirectly)
...
Allosteric regulation
The modifaction of enzyme activity through
interactino of molecules with specific sites on the
enzyme other than the active site (called allosteric
sites)
Alveoli
(singular alveolus
...
Alveoli are the site of gas exchange
in the respiratory system
...
For example, the gene may be
for eye color, and the allels include those for brown
eyes, those for blu e eyes, those green eyes, etc
...
6
Amino Acid
The monomer of a protein; amino acids hae an amio
group on one end fo the molecule and a carboxylic
acid group on the other, and of the of 2 different side
chains
...
The nucleotide sequence at this end is CCA
Aminoacyl
tRNA
A tRNA with an amino acid attached
...
d
Aminion
A sac filled with fluid (aminotic fluid) that surroudns
and protects a developing embryo
...
g
...
7
Amylase
An enzyme that digests starch into disaccharides
...
Anabolism
The process of bulidng complex structures out of
simpler precursors, e
...
synthesizing protiens from
amino acids
...
Analogous structures arise
from convergent evolution
...
It has an internal part made of smooth
muscle (thus involuntary) and an external part made
of skeletal muscle (thus voluntary)
...
During anaphase,
replicated chromosmes are split apart at their
centromeres (the sister chromatids are separated
from each other) and moved to opposite sides of the
cell
...
During anaphase I the
rplicated homologous chromosomes are separated
(the tetrad is split) and pulled to opposite sides of
the cell
...
During anaphase II the
sister chromatids are finally spearated at their
centromeres and puled to opposite sides of teh cell
...
Androgens
Mal sex hormones
...
Angiotensin
A normal blood protein produced by the liver,
angiotensin is converted to angiotensim I by renin
(secreted by kidney when blood pressur falls)
...
Angiotensin II is a powerful systemic vasocontrictor
ans stimulator of aldosterone relase, both of which
result in an increase in blood pressure
...
For example, muscles that move a
join in oppoiste direction are said to be antagonists
...
The anterior
pituitary is controlled b yreleasing and inhibiting
factors from the hypothalamus
...
The foreign proteins are called
antigens
...
Anticodon
A sequence of three nucleotides (found int he
anticodon loop of tRNA) that is complementary to a
specific codon in mRNA
...
Antidiuretic hormone (ADH)
Also called vasopressin, this hormone is produced in
the hypothalamus and secreted by teh posterior
pituitary gland
...
Also raises
blood pressure by inducing moderate
vasoconstriction
...
10
Antigen presenting cell
Cells that possess MHC II (B cells and macrophages)
and are able to display bits of ingested antigen on
their surface in order to activate T cells
...
Aorta
The largest artery in teh body; the aorta carries
oxygenated blood away from the left ventricle of the
heart
...
11
Aqueous humor
A thin, watery fluid found in teh anterior segment of
the eye (between the lens and the cornea)
...
Artery
A blood vessel that carries blood away from the heart
chambers
...
A site
Amino-acyl tRNA site; the site on a ribosome where
a new amino acid is added to a growing peptide
...
It is essentially a channel that
llows H+ ions to flow from teh intermembrane space
to the matrix (down teh gradeint produced by the
enyzmes complexes of the electron transport chain);
as the H= ions flow through the channel, ATP is
synthesized from ADP and Pi
12
Atrioventricular bundle (AV) bundle
Also known as the Bundle of His, this is the first
portion of the cardiac conduction system, after the
AV node
...
The cardiac impulse is
delayed slightly at teh AV node, allowing the
ventricles to contract just after the atria contract
...
The tricuspid valve separates teh right
atrium from the right ventricel, and the bicuspid
(mitral) valves separates the left atrium from the left
ventricle
...
Atrium
One of the two small chambers in the heart that
receive blood and pass it on to the ventricles
...
Attachment
The first step in viral infection
...
13
Auditory tube
The tube that connects the middle ear acity with the
pharynx; also known as the Eustachian tube
...
Autoimmune reaction
An immune reaction directed against normal
(necessary ) cells
...
Autonomic nervous system (ANS)
The division of the periperal nervsous system that
innervates and cotnrols the visceral organs
(everything but the skeletal muscles)
...
Autosome
A chromosome that does not determine gender (is
not a sex chromosome)
...
Autotroph
An organism that makes its own, typically using CO2
as a carbon source
...
Auxotrphs must ave the needed
substance (the auxiliary trophic substance) added to
their medium in order to survive
...
For example, a bacterium that
cannot syntehisze leucine would be a leucine
auxotroph, and would be indicated as leu- (w/ a
superscripth, though)
Avascular
Lacking a blood supply; cartialge is
an example of this
Axon
A long projection off the cell body of a neruon down
which an action potential can be propagated
...
Bacteriophage
A virus that infects a bacterium
...
Basement membrane
A layer of collagen fibers that separates epithelial
tissue from connective tisse (example of epithelial
cells in digestive tract) - they are actual connective
tissue
...
The fibers of the basilar
membrane are short and stiff near the oval windown
and long and fleaxible near the apex of the cochlea
...
B cell
A type of lymphocyte that can recognize (bind to) an
antigen adn secrete an antibody specific for that
antigen
...
- must be
activated by Helper T cell also, though
...
THis ion results from the dissociation of
carbonic acid, together wiht carbonic acid forms the
the major blood buffer system
...
16
Bile
A green fluid made from cholesterol and secreted by
teh liver
...
Bile isn an amphipathic molecule that is
secreted itno the small intestine when fats are
present, adn serves to emulsify the fats for better
digestion by lipases
...
THe
bacterium simply grows in size until it has doubled
its cellular components, then it replicates its genone
and splits into two
...
Bipolar neurons are typically associated with sensory
organs; an example is the bipolar neuron in the
retina of the eye
...
Blastocyst
A fluid-filled sphere formed about 5 days after
fertilization of an ovum that is made up of an outer
ring of cells and inner cell mass
...
Bohr effect
The tendency of certain factors to stablize the
hemoglobin in the tense conformation, thus
reducing its affinity for oxygen and enhancing the
relase of oxygen to the tissues
...
Note
that the Bohr effect shifts the oxy-hemolobin
saturation curve to the right
...
Red bone marrow is found in regiosn
of spongy bone and is the site of blood cell (red and
white) production
...
Bowman's capsule
The region of the nephron that surrounds the
glomerulus
...
Bronchioles
Very small air tubes int eh respiratory system
(diameter 0
...
0 mm)
...
Brush border enzymes
Enzymes secreted by the mucosal cells lining the
intestine
...
Bulbourethral galnds
Small paired gland found inferior to the prostate in
males and at the posterior end of the penile urethra
...
18
Calcitonin
A hormone produced by the C-cells of the thyroid
gland that decreases serum calcium levels
...
Calcitriol
A hormone produced from vitamin D that acts in
essentially the same manner as parathyroid
hormone
...
Calmodulin is
particularly important in smooth muscle cells, where
binding of Ca2+ allows calmodulin to activate
myosin light-chian kinase, the first step in smooth
muscle cell contraction
...
Capacitation
An incrase in the fragility of the membranes of
sperm cells when exposed to the female reproductive
tract
...
19
Capilary
The smalles of all blodo vessles, typically having a
diamtere just large neough for blood cells to pass
through in single file
...
Capsid
The outer protein coat of a virus (the
whole coat)
Carbohydrates
Molecules made from monosaccharides that serve as
the primary source of cellular energy,
...
Carbonic anhydrase
An enzyme present in erythrocytes (as well as in
other places) that catalyzes the conversion of CO2
and H2O into carbonic acid (H2CO3)
...
The cells of the conduction
system are essentially cardiac muscle cells, but lack
the contractile fibers of the muscle cells, tus they are
able to transmit impulses (action ptnetials) more
quickly and efficiently that cardiac muscle tissue
...
20
Cardiac muscle
The muscle tissue of the heart Cardiac muscle is
striated, uninucleate, and under involuntary control
(controlled by teh autonomic nervous system)
...
Cardiac output
The volume of blood pumped out of the heart in one
minute (vol/min); the product of the stroke volume
(vol/beat) and the heart rate (beat/min)
...
Carrier protein
An integral membrane protein that undergoes a
conformational change to move a molecule from one
side of the membrane to another
...
Cartilage
A strong connective tissue with varying degrees of
flexibility
...
(2)
Hyaline cartilage is more rigid than elastic cartilage,
and forms the cartilages of the ribs, the respiratory
tract, and all joints
...
Catabolism
The process of breaking down large molecules into
smaller precursors, e
...
digesion of starch into
glucose
...
Catalyst
Something that increases the rate of a chemical
reaction by reducing the activation energy for that
reaction
...
cDNA
Complementary DNA
...
Because of eukaryotic
mRNA splicing, cDNA contains no inrons
...
Cell surface receptor
An integral membrane proteint hat binds
extracellular signaling molecules, suchas hormones
and peptides
...
The central canal contains blood
vessels, lymphatic vessels, lymphatic vessels, and
nerves
...
Central
chemoreceptors
Receptors in the central nervous system that
monitor the pH of cerebrospinal luid to help regulate
ventilation rate
...
Centriole
A structure composed of a ring of nine microtube
triplets, found in pairs in the MTOC (microtubule
organizing center) of a cell
...
Centromere
A structure near the middle of eukaryotic
chromosomes to which the fibers of the mitotic
spindle attach during cell division
...
Cerebral cortex
A thin (4 mm) layer of gray matter on the surface of
the cerebral hemispheres
...
Cerebrospinal fluid
A clear fluid the circulates around through the brain
and spinal cord that helps to physially support teh
brain and act as a shock absorber, and taht also
exchanges nutrients and wastes with teh brain and
spinal cord
...
Cervix
The opening to the uterus The ervix is typically
plugged with a sticky acidic mucus during non-fertile
times (to form a barrier against the entry of
pathogens), however during ovulation the mucus
becomes more watery and alkaline to facilitate sperm
entry
...
See also entries under
'ion channel', 'voltage-gated channel', and
'ligand-gated channel'
...
Chemoreceptor
A sensory receptor that responds to specific
chemicals
...
Chemotaxis
Movement that is directed by chemical gradients,
such as nutrients or toxins
...
25
Chief cells
Pepsinogen-secreting cells foudn at teh bottom of
the gastric glands
Chitin
A poysaccharide found in the cell walls of fungi and
in the exoskeletons of insects
...
It
promotes release of bile from the gallbladder and
pancreatic juice from the pancreas,and reduces
stomach motility
...
Cholesterol is the precursor for steroid hormones,
and is used to manufacture bile salts
...
26
Chorion
The portion of the placenta derived
from the zygote
...
Chromosome
A single piece of double-stranded DNA; part of the
genome of an organism
...
Chylomicron
A type of lipoprotein; the form in which absorbed
fats from the intestines are transported to the
circulatory system
...
27
Chymotrypsin
One of the main pancreatic proteases; it is activated
(from chymotrypsinogen) by trypsin
...
Teh microtubules are conneted with a
contractile protien called dynein
...
They are
particularly important in the respiratory system,
where they sweep mucus out of the trachea and up to
the mouth and nose
...
Circular smooth
muscles
The inner layer of smooth muscle in the wall of the
digestive tract
...
Certain areas of the
circular muscle are thickened to act as valves
(sphincters)
...
Typically cel surface receptors are associated with
clathrin-coated pits at the plasma membrane
binding of the ligan to the receptor trigger
invagination (example: cholesterol uptake via
lipoprotein endocytosis)
...
Codominance
A situation in which a heterozygote displays the
phenotype associated with each of the alleles, e
...
,
human blood type AB
...
Cofactor
An **inorganic molecule that associates
non-covalently with an enzyme and that is required
for the proper functioning of the enzyme
Collagen
A protein fiber with a unique triple-helix that gives it
great strength
...
g
...
Collecting duct
The portion of the nephron where water
reabsorption is regulated via antidiuretic hormone
(ADH)
...
Common bile duct
The duct that carries bile from the gallbladder and
liver to the small intestine (duodenum)
...
Compact bone forms the
diaphysis of the the long bones, and the outer shell
of the epiphyses and all other bones
...
When
the inhibitor is bound, no product can be made
...
Cones
Photoreceptors in the retina of the eye that responds
to bright light and provide color vision
...
31
Connective tissue
One of the four basic tissue types in the body
(epithelial, connective, muscle, and nervous)
...
Convergent evolution
A form of evolution in which different organisms are
placed into the same environment and exposed to
teh same selection pressures
...
As a result,
they may share functional, but not structural
similarity (because they possessed different startgin
materials)
...
Cooperativity
A type of substrate binding to a multi-active site
enzyme, in which the bnidng of one substrate
molecule facilitates teh binding of subsequent
substrate molecules
...
substrate concentration appears sigmoidal
...
Cornea
The clear portion of the tough outer layer of teh eye
ball, found over the iris and pupil
Corona radiata
The layer of granulosa cells taht surround an oocyte
after is has been ovulated
...
The coronary arteries branch off teh
aorta and carry oxygenated blood to the cardiac
tissue
...
Corpus callosum
The largest bundle of white matter (axons)
connecting th two cerebral hemispheres
...
' The remnants of an ovarian follicle
after ovulation has occurred
...
Some estrogen is also secreted
...
g
...
Corticosteroids
Steroid hormones secreted from the adrenal cortex
...
Aldosterone is the principal
mineralocorticoid, and cortisol is the principal
glucorcorticoid
...
This steroid hormone is released
ruing stress, causing increased blood glucose levels
and reducing inflammation
...
Creatine Phosphate
An energy storage molecule used by muscle tissue
...
Cristae
The folds of the inner membrane of
a mitochondrion
Cross bridge
The connection of a mosin head group to an actin
filament during muscle contraction (the sliding
filament theory)
...
34
Cyclic AMP (cAMP)
A cyclic version of adenosine monophosphate, where
the phosphate is esterified to both the 5' and 3'
carbons, forming a ring
...
' It serves to activate
cAMP-dependent kinases, which regulates the
activity of other enzymes in the cell
...
Cytokinesis
The phase of mitosis during which the cell physically
splits into two daugter cells
...
Cytosine
One of the four aromatic bases found in DNA and
RNA
...
Dendrite
A projection of the cell body of a neuron that recieves
a nerve impulse form a different neuron and send
the impulse to the cell body
...
Dense tissues are typically strong
(e
...
bone, cartilage, tendons, etc
...
Dermis
A layer of connective tissue underneath the
epidermis of the skin
...
Desmosome
A general cell junction, used
primarily for adhesion
...
Note that the cell is not differentiated at
this point; determination comes before
differentiation
...
Diaphragm
The primary muscle of inspiration
...
Although it is made of skeletal
muscle (and can therefore be voluntary controlled),
these stimulations occur autonomously
...
The diaphysis is hollow and
is made entirely from compact bone
...
Diastolic pressure
The pressure measured in the arteries while the
ventricles are relaxed (during diastole)
...
Differentiation
The specialization of cell types, especially during the
embryonic and fetal development
...
Diploid organism
An organism that has two copies of its genome it
each cell
...
Disaccharide
A molecule composed of two monosaccharides
...
Distal convoluted
tubule
The portion of the nephron tubule after the loop of
Henle, but before teh collecting duct
...
Divergent evolution
A form of evolution in which the same organism is
placed into different environments with different
selection pressures
...
The resulting (new) species may share structural
(but not necessarily functional) similarity; divergent
evolution produces homologous structures
...
Eukaryotes have a single version of
the enzyme, simply called DNA pol (not need to
know much detail); prokaryotes have three versions,
called DNA pol I, DNA pol II, and DNA pol III
...
Dorsal root ganglion
A group of sensory neuron cell bodies found just
posterior to the spinal cord on either side
...
The ganglia are part of the
peripheral nervous system (PNS)
...
Stop codons and (in
eukaryotes) the pol-A tail are found 'downstream
...
39
Dynein
A contractile protein connecting microtubules in the
'9+2- arrangement of cilia and eukaryotic flagella
...
Ectoderm
One of the three primary (embryonic) germ layers
formed during gastrulation
...
Edema
Swelling of tissues, sometimes caused by
inflammation letting into many white blood cells
(decreasing oncotic pressure at the end of the
capillaries & not letting as much water back into
capillaries & staying in tissues)
...
40
Efferent neuron
A neuron that carries information (action potentials)
away from the central nervous system; a motor
neuron
...
Ejaculation is a series of rhythmic contractions of
muscles near teh base of teh penis that increase
pressure in the urethra, forcing the semen out
...
THe ejection fraction is normally around 60% of the
end diastolic volume
...
d Elastin is found in great amounts in lung
tissue, arterial tissue, skin, and the epiglottis
...
- compared to chemical
synapse
...
NADH and FADH2 are
oxidized by tehse enzymes; the electrons are shuttled
down the chain and are ultimately passed to oxygen
and to produce water
...
Embryonic stage
The period of human development from
implantation through 8 weeks of gestation
...
The developing baby is
known as embryo during this time period
...
Emission is the
movement of sperm (via the vas deferens) and
semen into the urtehra in prepartion for ejaculation
...
42
Endocytosis
The uptake of material into a cell, usually by
invagination
...
Endoderm
One of the three primary (embryonic) germ layers
formed during gastrulation
...
Endometrial cycle
The 28 days of the menstrual cycle as they apply to
the events in the uterus
...
Endometrium
The inner epithelial lining of the uterus that thickens
and develops during the menstrual cycle, into which
a fertilized ovum can implant, and which sloughs off
during menstration if a pregnancy does not occur
...
Endospores have very rough outer shells
made of peptidoglycan and can survive harsh
conditions
...
43
Endosymbitoic theory
the theory that mitochondria and chloroplasts
originated as independent unicellular organsims
living in symbiosis with larger cells
Endotoxin
A normal component of the outer membrane of
Gram-negative bacteria
...
End plate potential
The depolarzation of the motor end
plate on a muscle cell
...
It
controls secretion and motility within teh Gi tract,
and is linked to the central nervous system
...
It
decreases the rate at which chyme leaves the
stomach and enters the small intestine
...
Envelope
A lipid bilayer that surrounds the capsid of an
animal virus
...
Not all annimal viruses possess and envelope
...
Enzymes are usually
proteins, although some RNAs have catalytic
activity
...
The epidermis is
made of epithelial tissue that is constantly dividing
at the bottom; teh cells migrate to teh surface (dying
along the way) to be sloughed off at the suface
...
45
Epiglottis
A flexible piece of cartilage in the larynx that flips
downward to seal teh trachea during swallowing
...
Epiphyseal plate
A band of carilage (hyaline) found between the
diaphysis and epiphyses of long bones during
childhood and adolescence
...
This is waht allows bone growth during
childhood
...
Epiphysis
One of the two ends of long bone (pl: eiphyses)
...
The spongy bone is
filled with red bone marrow, the stie of blood cell
formation
...
g
...
46
Epithelial tissue
One of the four basic tissue types in the body
(epithelial, connective, muscle, and nervous)
...
g
...
) or a glandular tissue
(e
...
the liver, the pancreas, the ovaries, etc
...
EPSP
Excitatory postsynaptic potential; a slight
depolarization of a postsynaptic cell, bringing the
membrane potential of that cell closer to the
threshold for an action potential
...
Erectile tissue is found in the penis, the
clitoris, the labia, and the nipples
...
47
Erythropoietin
A hormone produced and released by the kidney that
stimulates the production of red blood cells by the
bone marrow
...
Estrogen
stimulates the development of female secondary sex
characteristics during puberty, maintains those
characteristics during adulthood, stimulates the
development of a new uterine lining after
menstruation, and stimulates mammary gland
development during pregnancy
...
This
DNA is more accessible to enzymes and the genes in
euchromatin can be activated if needed
...
Eukaryotes can
be unicellular (protists) or multicellular (fungi,
plants and animals)
...
48
Excitation-contraction coupling
The mechanism that ensures tehat skeletal muscle
contraction does not occur without neural
stimulation (excitation)
...
When the
muscle is stimulated by a neuron, calcium is released
from the sarcoplasmic reticulum into teh cytosol of
the muscle cell
...
This allows mysoin and actin to interact
according to the sliding filament theory
...
Exocrine gland
A gland that secretes its product into a duct, which
ultimately carries the product to the surface of the
body or into a body cavity
...
Exocytosis
The secretion of a cellular product to the
extracellular medium through a secretory vesicle
...
Exons are typically
separated by introns (intervening sequences) that
are spliced out prior to translation
...
Some exotoxins cause
serious disease in humans (botulism, tetanus,
diptheria, toxic shock syndrome)
...
Expiration can be passive (caused by relaxation of
the diaphragm and elastic recoil of the lungs) or
active (caused by contraction of the abdominal
muscles, which increases intraabdominal pressure
and forces the diaphragm up past its normal relaxed
position)
...
Because the hydrophilic
nature of the molecule, it requires a special path
through the lipid bilayer
...
FADH2
The reduced from (carries electrons) of FAD (flavin
adenine dinucleotide)
...
50
Fascicle
A bundle of skeletal muscle cells
...
Fast block to
polyspermy
The depolarization of the egg plasma membrane
upon fertilization, designed to prevent the entry of
more than one sperm into the egg
...
This has the effect of stopping
the series of events when the products are plentiful
and the series is unnecesseary
...
Fermentation
The reduction of pyruvate to either ethanol or lactate
in order to regenerate NAD+ from NADH
...
Fertilization
The fusion of a sperm with an ovum during sexual
reproduction
...
Fertilization is
a species-specific process, requiring binding of a
sperm protein to an egg receptor
...
Bacteria that
possess teh F factor are known as F+ 'males'
...
During this stage the organs
formed in the embryonic stage grow and mature
...
Fibrinogen
A blood protein essential to blood clotting
...
Fibroblast
A generic connective tissue cell that produces fibers;
the progenitor of all other connective tissue cell
types
...
In the kidney, filtration refers specifically
to the movement of plasma across the capillary walls
fo the glomerulus, into the capsule and tubule of the
neprhon
...
52
Fimbriae
Fingerlike projection of the uterin (fallopian) tubes
that drape over the ovary
...
Flagella
A long, whip-like filament that helps in cell motility
...
Fluid mosaic model
the current understanding of membrane structure, in
which teh membrane iscomposed of a mix o lipids
and proteins (a mosaic) that are free to move fluidly
among themselves
...
53
FSH
A tropic hormone produced by the anterior pituitary
gland that targets the gonads
...
Follicular phase
The first phase of the ovarian cycle, during which a
follicle (an oocyte and its surroudning cells) enlarges
and matures
...
The follicle
secretes estrogen during this time period
...
Formed elements
The cellular elements of blood; erythrocytes,
leukocytes, and platelets
...
54
Frank Starling
mechanism
A mechanism by which the stroke volume of the
heart is increased by increasing the venous return of
the heart (thus stretching the ventricular muscle)
...
Cardiac and smooth muscle
tissues are examples of functional synctiums
...
The
gallbladder stores and concentrates bile produced by
the liver, and is stimulated to contrat by
cholecystokin (CCK)
...
Ganglion
A clump of gray matter (unmyelinated neuron cell
bodies) found in the peripheral nervous system
...
Gap junctions allow small
molecules to flow between teh cells, and are
important in cell-to-cell communication, for
example, in relaying the action potential between
cardiac muscle cells, and relaying nutrients between
osteocytes
...
During
gap phases the cell undergoes normal activity and
growth; G1 may include preparation for DNA
replication and G2 includes preparation for mitosis
...
Gastrin
A hormone released by teh G cells of the stomach in
the presence of food
...
Gastrulation
the division of the inner cell mass of a blastocyst
(developing embryo) into the three primary germ
layers
...
Gene
A portion of DNA that codes for some product,
usually a protein, including all regulatory sequences
...
56
Gene pool
The sum of all genetic material in a
population
...
Genome
All the genetic information in an organism; all of an
organism's chromosomes
...
In
a homozygous genotype, both alleles are the same,
whereas in a heterozygous gentorype the alleles are
different
...
If the change in free energy of a
reaction (Delta G, the free energy of the products
minus the free energy of the energy of the reactants)
is negative, the reaction will occur spontaneously
...
Glucagon
A peptide hormone produced and secreted by the
alpha cells, of the pancreas
...
s
Glycolipid
A membrane lipid consisting of a glycerol molecule
esteried to two fatty acid chains and a sugar
molecule
...
Golgi apparatus
A stack of membranes found near the rough ER in
eukaryotic cells that is involved in the secretory
pathway
...
58
Gonadotropin releasing hormone
(GnRH
A hormone released from the hypothalamus that
triggers the anterior pituitary to secrete FSH and
LH
...
G-protein linked receptor
A cell surface receptor associated with an
intracellular protein that binds and hydrolyzes GTP
...
When the GTP is hydrolyzed to GDP, the
protein becomes inactive again
...
Ovulation of the oocyte occurs from this type of
follicle
...
They stain
very lightly (pink) in Gram stain
...
59
Gram-positive bacteria
Bacteria that have a thick peptido glycan cell wall,
and no outer membrane
...
Granulosa cells
the majority of the cells surrouding an oocyte in a
follicle
...
Gray matter
Unmyelinated neuron cell bodies and short
unmyelinated axons
...
Growth hormone
stimulates whole body growth in children and
adolescents, adn increases cell turnover rate in
adults
...
Guanine is a purine; it pairs with cytosine
...
Gyrase
A prokaryotic enzyme used to twist teh single
circular chromosome of prokaryotes upon itself to
form supercois
...
Hair cells
Sensory receptors found in the inner ear
...
Haploid organism
An organism that has only a single copy of its
genome in each of its cells
...
Hardy-Weinberg law
A law of population genetics that states that the
frequencies of alleles in a given gene pool do not
change over time
...
A
population meeting all of these conditions, in which
the allele frequency is not changing, is said to be in
Hardy-Weinberg equilibrium
...
e
...
This helps to
maintain the uterine lining so that menstruation
does not occur
...
Helicase
An enzyme that unwinds the double helix of DNA
and separates the DNA strands in preparation for
DNA replication
...
Hematopoiesis
The synthesis of blood cells (occurs in the red bone
marrow)
Hemizygous gene
A gene appearing in a single copy in diploid
organisms, e
...
X-linked genes in human males
...
Each subunit contains a heme group, a
large multi-ring molecule with an iron atom at its
center
...
Hemophilia
An X-linked recessive disorder in which blood fails
to clot properly, leading to excessive bleeding if
injured
...
Hepatic portal vein
A vein connecting the capillary bed of the intestines
with the capillary bed of the liver
...
Heterochromatin
DNA that is densely packed around histones
...
63
Heterotroph
An organism that cannot make its own food, and
thus must ingest other organisms
...
Hexokinase
The enzymes that catalyzes the phosphorylation of
glucose to form glucose-6-phosphate in the first step
of glycolysis
...
Hexokinase is feedback-inhibited by
glucose-6-P
...
When conjugation takes place, it is
able to transfer not only the F factor, but also its
genomic DNA
...
Histones form octamers around which
DNA is wound to form a nucleosome
...
Homeostasis
The maintenance of relatively constant internal
conditions (such as temperature, pressure, ion
balance, pH, etc
...
Homologous
chromosomes
A pair of similar chromosomes that have the same
genes in the same order, but may have different
versions (alleles) of those genes
...
Humans have 23
pairs of homologous chromosomes
...
Homologous
structures arise from divergent evolution
...
The allelles can both be
dominant (homozygous dominant) or both be
recessive (homozygous recessive)
65
Humoral immunity
Specif ic defense of the body by antibodies, secreted
into the blood by B-cells
...
Hyperpolarization
The movement of the membrane potential of a cell
away from rest potential in a more negative
direction
...
The
hypodermis helps to insulate the body and protects
underlying muscles and other structures
...
66
Hypothalamic-pituitary portal
system
A set of veins that connect a capillary bed in the
hypothalamus (the primary capillary plexus) with a
capillary bed in the anterior pituitary gland (the
secondary capillary bed)
...
Hypothalamus
The portion of the diencephalon involved in
maintaining body homeostasis
...
H zone
The region at the center of an A band of a sarcomere
that is made up of myosin only
...
I band
The regino of the sarcomere made up only of thin
filaments
...
I bands
alternate with A bands to give skeletal and cardiac
muscle a striated appearance
...
Ileocecal valve
The sphincter that separates the final part of the
small intestine (the ileum) from the fron part of the
large intestine (the cecum)
...
The ileocecal
valve is stimulated to relax by the presence of food in
the stomach
...
Implantation
The burrowing of a blastocyst (a developing embryo)
into the endometrium of the uterus, typically
occuring about a week after fertilizaiton
...
g
...
Inducible enzymes
An enzyme whose transcription can be stimulated by
an abundance of its substrate (as opposed to
repressible enzyme)
...
Induction
The process by which neighboring cells can influence
the determination (and subsequent differentiation)
of a cell
...
Inflammation is characterized by four cardinal
symptoms; redness (rubor), swelling (tumor), heat
(calor), and pain (dolor)
...
Innate immunity
General, non-specific protection to the body,
including the skin (barrier), gastric acid, phagocytes,
lysozyme, and complement
...
)
Inspiration
The movement of air into the respiratory tract
...
69
Insulin
A peptide hormone produced and secreted by the
Beta cells of the pancreas
...
Integral membrane protein
A protein embedded in the lipid bilayer of a cell
...
Intercalcated discs
The division between neighboring cardiac muscle
cells
...
Intercostal muscles
Muscles located in between the ribs that play a role
in ventilation
...
70
Intermediate filaments
Cytoskeletal filaments with a diameter in between
that of the microtubule and the microfilament
...
Interneuron
A neuron found completely within the central
nervous system
...
Internodal tract
The portion of the cardiac conduction system
between the SA node and the AV node
...
Interphase
includes G1, S phase, and G2
...
They are
stimulated by luteinizing hormone (LH)
...
In DNA, these intervening
sequences typically contain **regulatory sequences,
however, in RNA they are simply spliced out to form
the mature (translated) transcript
...
Ion channels
may be constitutively open (leak channels), or
regulated (voltage-gated or ligand-gated)
...
Iris
A pigmented membrane found just in from the lens
of the eye
...
The iris
regulates the diameter of the pupil in response to the
brightness of light
...
Different cell types
wihtin the inslets secrete insulin, glucagon, and
somatostatin
72
Jejunum
The middle (approximtely 40%) of
the small intestine
...
It is involved in regulating blood pressure
...
The cells of the afferent artery at the juxtaglomerular
apparatus
...
Keratin
A protein-based substance secreted by cells of the
epiderms as they migrate outward
...
Kinase
An enzyme that phosphorylates something else
...
73
Krebs cycle
The third stage of cellular respiration, in which
acetyl-CoA is combined with oxaloacetate to form
citric acid
...
In the
process, 3 molecules of NADH, 1 molecule of
FADH2, and 1 molecule of GTP are formed (per
acetyl-CoA)
Labia
The folds of skin that enclose the vaginal and
urethral openings of females
...
Labor contractions are part of a
positive feedback cycle, during which the baby's
head stretches the cervix, which stimulates stretch
receptors that activate the hypothalamus, which
stimulates the posterior pituitary to release oxytocin,
which stimulates strong uterine contractions (labor
contractions) that cause the baby's head to stretch
the cervix
...
Lacteals
Specialized lymphatic capillaries in the intestines
that take up lipids as well as lymph
...
A rise in lactic
acid usually accompanies an increase in physical
activity
...
Lagging strand
The newly forming daughter strand of DNA that is
replicated in a discontinuous fashion, via Okazaki
fragments that will ultimately be ligated together;
the daugther strand that is replicated in the opposite
direction that parallel DNA is unwinding
Lag phase
A short period of time **prior to exponential growth
of a bacterial population during which no, or very
limited, cell division occurs
...
The primary funcion of the large intestine is to
reabsorb water and to store the feces
...
The larynx has three main functions: (1) its
rigidness ensures that the trachea is held open
(provides an open airway)
...
75
Law of Independent Assortment
Mendel's seond law
...
e
...
Law of Segregation
Mendels' first law
...
Lawn
A dense grwoth of bacteria that covers the surface of
a petri dish
...
Leak channel
An ion channel that is constitutively open, allowing
the movement of teh ion across the plasma
membrane according to its concentration gradient
...
Maximum tension
(contraction strength) is achieved at sarcomere
lengths between 2
...
2 microns
...
Leukocyte
A type of white blood cell; leukocytes are either B or
T cells and are involved in disease defense
...
Ligand
The specific molecule that binds to a
receptor
...
Once
opened, the channel allows the ion to cross the
plasma membrane according to its concentration
gradient
...
77
Ligase
An enzyme that connects two fragments of DNA to
make a single fragment; also called DNA ligase
...
Lipoprotein
Large conglomerations of proteins, fats, and
cholesterol that transport lipids in the bloodstream
...
Linkage
The failure of two separate genes to boey the Law of
Independent Assortment, as might occur if the genes
were found close together on the same chromosome
...
The most common forms in
which lipids are found in the body are as
triglycerides (energy storage), phospholipids (cell
membranes), and cholestero (cell membranes and
steroid synthesis)
...
The liver
has many roles, including procesing of
carbohydrates and fats, synthesis of urea, production
of blood proteins, production of bile, recycling heme,
and storage of vitamins
...
THis is generally
accomplished via metabolic wastes (such as CO2)
that act as vasodilators
...
Long bone
The most common class of bone in the body, long
bones have a well-defined shaft (the diaphysis) and
two well-defined ends (the epiphyses)
...
When the longitudinal muscle
contracts the tube shortens
...
The loop of Henle sets up a
concentration gradient in the kidney such that from
the cortex to the renal pelvis osmolarity increases
...
79
Loose connective
tissue
Connective tissue that lacks great amount of collagen
or elastic fibers (hence, loose), e
...
, adipose tissue
and areolar (general connective) tissue
...
Its function is to
prevent reflux of acid stomach contents into the
esophagus; note that it does ***not regulate entry
into the stomach*
...
g
...
) or a tube (e
...
, blood
vessels, ureters, etc
...
The corpus
luteum secretes progestrone and estrogen during
this time period, which typically lasts from day 15 to
day 28 of the menstrual cycle
...
Luteinizing Hormone
(LH)
A tropic hormone produced by the anterior pituitary
gland that targets the gonads
...
80
Lymphatic system
A set of vessels in the body that runs alongside the
vessels of the circulatory system
...
It serves to return excess tissue fluid
(lymph) to the circulatory system, and filters the
fluid through millions of white blood cells on its way
back to the heart
...
Lymphocyte
The second most common of the five classes of
leukocytes
...
B-cells produce and secrete antibodies and
T-cells are invovled in cellular immunity
...
Lysogenic cycle
A viral life cycle in which the viral genome is
incorporated into the host genome where it can
remain dormant for an unspecified period of time
...
81
Lysosome
A eukaryotic organelle filled with digestive enzymes
(acid hydrolases) that is involved in digestion of
macromolecules such as worng organelles or
material ingested by phagocytosis
...
Lysozyme is
produced in the end stages of the lytic cycle so that
new viral particles can escape their hosst; it is also
found in human tears and human saliva
...
Macrophage
A large, non-sepcific, phagocytic cell of the immune
syste
...
Macula densa
The cells of the distal tubule at the juxtaglomerular
apparatus
...
If a
drop is osmolarity is sensed, the macula densa
dilates the afferent arteriole (to increase the blood
pressure in the glomerulus and thus increase
filtration) and stimulates the juxtaglomerular cells to
secrete renin (to raise systemic blood pressure)
...
Matrix
The interior of a mitochondrion (the region bounded
by the inner membrane)
...
Mechanoreceptors
A sensory receptor that responds to mechanical
disturbances, such as shape changes (being
squashed, bent, pulled, etc
...
Medium
The environment in which or upon which bacteria
grow
...
'Minimal
medium' contain nothing but glucose
...
g
...
83
Medulla oblongata
The portion of the hindbrain that controls
respiratory and blood pressure, and specialized
digestive and respiratory functions such as vomiting,
sneezing, and coughing
...
Meiosis usualy
produces haploid gametes in organisms that undergo
sexual reproduction
...
Meiosis I and II can both be subdivided into four
phases similar to those in mitosis
...
Melanin production is
increased on sun exposure and helps prevent cllular
damage due to UV radiation
...
Memory cells do not actively fight the current
infection, but patrol the body in case of future
infection with the same antigen
...
Meninges
The protective, connective tissue wrapping of the
central nervous system (the dura mater, arachnoid
mater, and pia mater)
...
Menopause typically begins
in the late 40s
...
Estrogen and progesterone levels
are low during this time period
...
Mesoderm
One of the three primary (embryonic) germ layers
formed during gastrulation
...
Metaphase
The secon phase of mitosis
...
Metaphase I
The second phase of meiosis I
...
85
Metaphase II
The second phase of meiosis II
...
MHC
Major Histocompatability complex, a set of proteins
found on the plasma membranes of cells that help
display antigen to T cells
...
MHC II is found
only on macrophages and B cells
...
Microfilament
The cytoskeleton filaments with the smallest
diameter
...
They are dynamic
filaments, constantly beig made and broken down as
needed, and are responsible for events such as
pseudopod formation and cytokenesis during
mitosis
...
Microtubules are composed of two types of protein,
alpha tubulin and beta tubulin
...
Microtubules form the
mitotic spindle during cell division, form the base of
cilia and flagella, and are used for intracellular
structure and transport
...
86
Midbrain
The portion of the brain responsible for visual and
auditory startle reflexes
...
Contraction is
stimulated by oxytocin, which is released from the
posterior pituitary when the baby begins nursing
...
Mitochondrion
An organelle surrounded by a double=membrane
(two lipid bilayers) where ATP production takes
place
...
Mitosis
The phase of the cell cycle during which the
replicated genome is divided
...
87
Monocistronic mRNA
mRNA that codes forsingle type of protein, such as is
found in eukaryotic cells
...
Monosaccharides
have the general chemical formula CnH2nOn, and
common monosaccharides include glucose, fructose,
galactose, and ribose
...
Because there is very little growth of
these cells during cleavage, the morula is ony about
as large as the original zygote
...
Motor unit
A motor neuron and all the all the skeletal muscle
cells it innervates
...
g
...
Small motor untis are
found in smaller muscles (e
...
the rectus muscles
that controle movements of the eyeball, the fingers)
and produce more precise movements
...
mRNA
Messenger RNA; the type of RNa that is read by a
ribosome to synthesize protein
...
The cilia continually beat, sweeping
contaminated mucus upward toward the pharynx
...
Mullerian ducts
Earlier embryonic ducts that can develop into femal
internal genitalia in the absence of testosteron
...
Multipolar neuron
A neuron with a single axon and multiple dendrites;
the most common type of neuron in the nervous
system
...
Myelin
An insulating layer of membranes wrapped around
the axons of almost all neurons in the body
...
Myofiber
A skeletal muscle cell, also known as a muscle fiber
...
90
Myofibril
A string of sarcomeres with a skeletal muscle cell
(hence smaller than myofiber)
...
Myoglobin
A globular protein found in muscle tissue that has
the ability to bind oxygen
...
Muscles that
participate in endurance activities (including cardiac
muscle) have abundant supplies of myoglobin
...
The myometrium is
made of smooth muscles that retains its ability to
divide in order to accomodate the massive size
increases that occur during pregnancy
...
Myosin
One of the contractie proteins in muscle tissue
...
Myosin has intrinsic ATPase activity and
can exist in two conformation, either high energy or
low energy
...
As its name
implies, this kinase phosphorylates myosin,
activating it so that muscle contraction can occur
...
This is the most common electron
carrier in cellular respiration
...
Natural selection
The mechanism described by Charles Darwin that
drives evolution
...
These organisms survive and
reproduce more than those that do not possess the
beneficial genes, thus these genes are passed on to
offspring, making the offspring better adapted
...
Nephron
The function unit of the kidney
...
The nephron empties into collecting ducts,
which empty into the ureter
...
The neuron is a highly specialized
cell, designed to transmit action potentials
...
At the NMJ, the muscle cel lmembrane is
invaginated and the axon terminus is elongated so
that a greater area of membrane can be depolarized
at one time
...
Examples are acetylcholine,
norepinephrine, GABA, dopamine, and others
...
Neuralation begins when a section
of the ectoderm invaginates and pinches off to form
the neural groove, which ultimately forms the neural
tube, from which the brain and spinal cord develop
...
Nociceptors are found everywhere in
the body except for the brain
...
Action potentials can 'hump' from node to
node, thus increasing the speed of conduction
(saltatory conduction)
...
THis changes the three-dimensional shape of
the enzyme such that it can no longer catalyze the
reaction
Nondisjunction
The failure of homologous chromosomes or sister
chromatids to separate properly during cell division
...
Nonsense mutation
A point mutation in which a condon that specifies an
amino acid is mutated into a stop (nonsense) codon
...
Nuclear envelope
The membrane surrounding the DNA in eukaryotic
cells made of two lipid bilayers
...
Nuclear pore
A protein channel in the nuclear envelope that llows
the free passage of molecules smaller than 60 kD
...
Nucleoside
A structure composed of a ribose molecule linked to
one of the aromatic bases
...
Nucleosome
A structure composed of two coils of DNA wrapped
around an octet of histone proteins
...
95
Nucleotide
A nucleoside with one or more phosphate gropus
attached
...
Deoxynucleoside
triphosphates (dNTPs) are the building blocks of
DNA; in these molecules, the ribose is replaced with
deoxyribose
...
The nucleus contains the genome and is the site of
replication and transcription
...
They
are also wrapped around a single histone, called
linker histone - may not really have to know
...
Obligate anaerobe
An organism that can only survive in the absence of
oxygen (anaerobic metabolism); oxygen is toxic to
obligate anaerobes
...
Olfactory receptors
Chemoreceptors in the upper nasal cavity that
respond to odo chemicals
...
Oogonium
A *precursor* cell that undergoes mitosis during
fetal development to produce more oogonium
...
Operator
A specific DNA nucleotide sequence where
transcriptional regulatory proteins can bind
...
An example is the
lac operon found in prokaryotes
...
There are no photoreceptors in the optic disk
...
The ptic
nerve is made up of the axons of the ganglion cells of
the retina
...
The Organ of Corti is the
site where auditory sensation is detected and
transduced to action potentials
...
Organogenesis begins after
gastrulation and is completed by the eight week of
gestation
...
In males, organs
includes emission and ejaculation; in females it is
mainly a series of rhythmic contraction of the pelvic
floor muscles and the uterus
...
Prokaryotes typically have a
single origin of replication, while eukaryotes have
several per chromosome
...
NOte that the water concnetration
gradient is opposite to the solute concentration
gradient, since where solutes are concentrated, water
is scarce
...
Osmotic pressure is essentialy a measure
of the concentration of a solution
...
Thus, highly
concentrated solutions are said to have high osmotic
pressures
...
The
malleus is atached to the tympanic membrane and
the stapes is attached to the oval window of the
cochlea
...
Osteoclast
A phagocytic-like bone cell that breaks down bone
matrix to release calcium and phosphate into the
bloodstream
...
Osteon
The unit of combact bone, also called a Haversian
system
...
Compact bone is laid down around
the central canal in rings (lamellae)
...
The outer ear is
separated from the middle ear by the tympanic
membrane (the eardrum)
...
Ovarian cycle
The 28 days of the menstrual cycle as they apply to
events in the ovary
...
Ovary
The female primary sex organ
...
Ovulation
The release of a secondary oocyte (along with some
granulosa cells) from the ovary at the approximate
midpoint of the menstrual cycle (typically around
day 14)
...
Oxaloacetate
A four-carbon molecule that binds with the
two-carbon acetyl unit of acetyl-CoA to form citric
acid in the first step of the Krebs cycle
...
Oxidative phosphorylation
The oxidation of high-energy electron carriers
(NADH and FADH2) coupled to the phosphorylation
of ADP, producing ATP
...
Oxytocin
A hormone released by the posterior pituitary that
stimulates uterine contractions during childbirth
and milk ejection during breastfeeding
...
Because the SA node
has the fastest leak, it typically reaches the threshold
for the pacemaker potential before any other region
of the conduction system, and thus sets the pace of
the heart
...
The first is an exocrine role: to produce digestive
enzymes and bicarbonate, which are delivered to the
small intestine via the pancreatic duct
...
102
Pancreatic duct
The main duct of the pancreas
...
Parasite
An organism that requires the aid of a host organism
to survive, and that harms the host in the process
...
It causes
a general decrease in body activities such as heart
rate, respiratory rate, and blood pressure, and an
increase in blood flow to the GI tract and digestive
function
...
Parathyroid hormone (PTH)
A hormone produced and secreted by the
parathyroid glands that increases serum calcium
levels
...
Parietal cells
Cells found in gastric glands that secrete
hydrochloric acid (for hydrolysis of ingested food)
and gastric intrinsic factor (for absorption of vitamin
B-12)
...
Partial pressures are
used to describe the amounts of the various gases
carried in the bloodstream
...
Passive
transport relies on concentration gradients to provie
the driving force for movement, and includes both
simple and facilitated diffusion
...
Penetration
The second step in viral infection, the injection of the
viral genome into the host cell
...
Pepsin is secreted in its
inactive form (pepsinogen) and is activated by
gastric acid
...
Peptide hormone
A hormone made of amino acids (in some cases just
a single, modified amino acid)
...
An
exception is thyroxine, which is hydrophobic enough
to enter the cells easily
...
Peptidoglycan
A complex polymer of sugars and amino acids; the
substance from which bacterial ell walls are made
...
105
Peripheral membrane protein
A protein that is associated with the plasma
membrane of a cell, but that is not embedded in the
lipid bilayer
...
Periperal nervous
system
All parts of the nervous system except for the brain
and spinal cord
...
Peripheral resistance increases if arteries
constrict (diameter decreases), and an increase in
peripheral resistance leads t o an increase in blood
pressure
...
The
peptidoglycan cell wall is found in the periplasmic
space, and this space sometimes contains enzymes to
degrade antibiotics
...
g
...
)
106
Peroxisome
Small organelles that contain the hydrogen peroxide
produced as a byproduct of lipid metabolism
...
Phagocytosis
The non-specific uptake of solid material by a cell
accomplished by englufing the particle with plasma
membrane and drawing it into the cell
...
The pharynx is divided into three
regions, named for their location
...
The nasopharynx is a passageway for air only,
but the oropharynx and laryngopharynx are
passageways for both air and food; consequently
they are lined with a much thicker layer of cells to
resis damage due to abrasion
...
Phenotypes are usually described as
dominant or recessive
...
This is the main regulatory step of
glycolysis
...
107
Phospholipid
The primary membrane lipid
...
Additional, highly
hyrohpilic groups are attached to the phosphate,
making this molecule extremely amphipathic
...
Pilus
A long projection on a bacterial surface involved in
an attachment, e
...
, the sex pilus attaches F+ and Fbacteria during conjugation
...
108
Placenta
An organ that develops during pregnacy, derived in
part from the mother and in part from the zygote
...
The placenta is formed during the first three
months of pregnancy
...
Fetal
capillaries grow into the placental villi, which are
surrounded by a pool of maternal blood
...
Plaque
A clear area in a lawn of bacteria
...
Plasma
The liquid portion of blood; plasma contains water,
ions, buffers, sugars, proteins, etc
...
Plasma cell
An activated B cell that is secreting
antibody
...
Platelets
Extremely small pseudo-cells in the blood, important
for clotting
...
Pleiotropic gene
A gene that has effects on several different
characteristics
...
Pleural pressure
The pressure in the (theoretical) space between the
lung surface and the inner wall of the chest cavity
...
Polar body
A small cell with extremely little cytoplasm that
results from the unequal cytoplasmic divsion of the
primary (produces the first polar body) and the
secondary (produces the second polary body)
oocytes during meiosis (oogenesis)
...
Poly-A tail
A string of several hundred adenine nucletodies
added to the 3' end of the eukaryotic mRNA
...
Polycistronic mRNa is a characteristic of
prokaryotes
...
POlysaccharides are
typically energy-storage molecules (glycogen in
animals, starch in plants) or structural molecules
(cellulose in plants, chitin in exoskeletons)
...
This occurs in some animals, but in humans,
blocks to polyspermy exist (the fast block and the
slow block) so that only a single sperm can penetrate
the oocyte
...
Pore
A pathway through a plasma membrane that restrics
passage based only on the size of the molecules
...
Portal systems
A system of blood vessels where the blood passes
from arteries to capillaries to veins, then through a
second set of capillaries, and then through a final set
of veins
...
Posterior pituitary gland
Also known as the neurohyophysis, the posterior
pituitary is made of nervous tisssue and stores and
secretes two hormones made by the hypothlamus;
oxtytocin and ADH
...
112
Postganglionic neuron
In the autonomic division of the PNS, a neuron that
has its *cell body located in the autonomic ganglion*
(where a preganglionic neuron synapses with it) and
whose axon synapses with the target axon
...
Leak
channels are constitutively open and allow their
specifi ion to move across the membrane according
to its gadient
...
Power stroke
The step in the sliding filament theory during which
yosin undergoes a conformaitonal change to its low
energy state, in the process dragging the thin
filaments (and the attached Z lines) toward the
center fo the sarcomere
...
Preganglionic neuron
In the autonomic divison of the PNS, a neuron that
has its *cell body located in the CNS*, and whose
axon extends into the PNS to synapse with a second
neuron at an autonoic ganglion
...
113
Primary bronchi
The first branches of the trachea
...
Primary immune
response
The first encounter with an antigen, resuling in
activated B cells (antibody secretion) and T cells
(cellular lysis and lymphocyte proliferation)
...
Primary oocytes
Diploid cells resulting from the activation of
anoogoium; primary oocytes are ready to enter
meiosis I
...
remember: cyte means ready to
undergo meiosis
...
DNA pol binds to the
primer and elongates it
...
Progesterone
A steroid hormone produced by the corpus luteum in
the ovary during the second half of the menstrual
cycle Progesterone maintains and enhances the
uterine lining for the possible implantation of a
fertilized ovum
...
Prokaryote
An organism that lacks a nucleus or any other
memrane-bound organelles
...
Proliferative phase
The second phase of the uterine (endometrial) cycle,
during which the endometrium (shed off during
menstration is rebuilt)
...
The proliferative phase typically lasts from
day 6 to day 14 of the menstrual cycle
...
The promoter is found upstream of the
start site, the location where transcription actually
takes place
...
During prophase the
replicated chromosomes condense, the spindle is
formed, and the nuclear envelope breaks apart into
vessicles
...
During prophase I the
replicated chromosomes condense, homologous
chromsomes pair up, crossing over occurs between
homologous chromosomes, the spindle is formed,
and the nuclear envelope breaks apart into vesicles
...
Prophase II
The first phase of meiosis II
...
Proprioreceptor
A receptor that responds to changes in body
position, such as stretch on a tendon, or contraction
of a muscle
...
116
Prostate
A small gland encircling the male urethra just
inferior to the bladder (only reproductive structure
not paired)
...
Prosthetic group
A non-protein, but organic, molecule (such as
vitamin) that is covalently bound to an enzyme as
part of the active site
...
Proteins are synthesized (translated)
by ribosomes, and function as enzymes, carriers,
structrual fibers, cell surface receptors, channels,
porters, hormones, etc
...
THe PCT is the site of most
reabsorption; all filtered nutrients are reabsorbed
here as well as most of the filtered water
...
117
Ptyalin
Salivary amylase
Pulmonary artery
The blood vessel that carries deoxygenated from the
right ventricle of the heart to the lungs
...
Pulmonary edema
The collection of fluid in the alveoli, particularly
dangerous because it impedes gas exchange
...
Pulmonary vein
One of several vessels that carry oxygenated blood
from the lungs to the left atrium of the heart
...
The diameter of pupil is
controlled by the iris in response to the brightness of
the light
...
They have a double rightn
structure and include adenine and guanine
...
The Purkinje fibers transmit the
cardiac impulse to the ventricular muscle
...
Pyrimidine bases
Aromatic bases found in DNa and RNA that have a
single-ring structure
...
119
Pyruvate dehydrogenase complex
A group of three enzymes that decarboxylates
pyruvate, creating an acetyl group and carbon
dioxide
...
In the process, NAD+ is reduced to
NADH
...
Pyruvic acid
The product of glycolysis; 2 pyruvic acid (pyruvate)
molecules are produced from a single glucose
molecule
...
Receptor-mediated endocytosis
A highly specific cellular uptake mechanism
...
Recessive
The allele in a heterozygou genotype that is not
expressed; the phenotype resulting from possession
of two recessive alleles (homozygous recessive)
...
The
recombination frequency is proportional to the
physical distance between genes on a chromosome
...
120
Rectum
The final portion of the large
intestine
...
Reflex arc
A relatively direct connection between a sensory
neuron and a motor neuron that allows an extremely
rapid response to a stimulus, often without
conscious brain involvement
...
Release factor
A cytoplasmic protein that binds to a stop codon
where it appears in the A-site of the ribosome
...
This
releases the finished protein from the final tRNA,
and allows the ribosome subunits and mRNA to
disassociate
...
Reabsorption reduces the amount of a substance in
the urine
...
Renin
An enzyme secreted by the juxtaglomerular cells
when blood pressure decreases
...
Replication
The duplication of
DNA
Relication fork(s)
The site(s) where the parental DNA double helix
unwinds during replication
...
Repolarization
The return of membrane potential to normal resting
values after a depolarization of hyperpolarization
...
Usually part of anabolism of product
...
Residual volume
The volume of air remaining in the lungs after a
maximal forced exhalation, typically about 1200 mL
...
Respiratory acidosis
A drop in blood pH due to hypoventilation (too little
breathing) and a resulting accumulation of Co2
...
Resting membrane potential
An electrical potential established across the plasma
membrane of all cells by the Na+/K+ ATPase and the
K+ leak channels
...
Restriction
endonuclease
A bacterial enzyme that recognizes a specific DNA
nucleotide sequence and that cuts the double helix at
a specific site within the sequence
...
The retina is
made up of a layer of photoreceptors, a layer of
bipolar cells, and a layer of ganglion cells
...
Retinal changes conformation when it
absorbs light, triggering a series of reactions that
ultimately result in an action potential being sent to
the brain
...
g
...
In order to integrate
its genome with the host cell genome, the virus must
first reverse trasncribe its RNA genome to DNA
...
Ribosome
A structure made of two protein subunits and rRNA;
this is the site of protein synthessis (translation) in a
cell
...
The S value refers to the
sedimentation rate during centrifugation
...
All prokaryotic and
eukaryotic RNa polymerases are DNa dependent;
they make a strand of RNa by reading a strand of
DNA
...
Prokaryotes have a
single RNA pol, while eukaryotes have three; in
eukaryotes, RNA pol I transcribes rRNA, RNA pol II
transcribes mRNA, and RNA pol III transcribes
tRNA
...
Rough endoplasmic reticulum
A large system of folded membranes within a
eukaryotic cell that has ribosomes bound to it, giving
a rough appearnce
...
rRNA
Ribosomal RNA; the type of RNA that associates
with ribosomal proteins to make a functional
ribosome
...
126
Rule of addition
A statistical rule stating that the probability of either
of two indpendent (and mutually exclusive) events
ocuring is the sum of their individual probabilities
minus the probability of them both occuring
together
...
Saltatory conduction
A rapid from of action potential conduction along
the axon of a neuron in which the action potential
appears to jump from nodde of Ranvier to node of
Ranvier
...
Sarcolemma
The plasma membrane of a muscle
cell
...
Sarcomeres are
bounded by Z lins, to which thin filaments attach
...
Sarcoplasmic
reticulum
The smooth ER of a muscle cell, enlarged and
specialized to act as a Ca2+ reservoir
...
Schwann cell
One of the two peripheral nervous system
supporting (glial) cells
...
Sclera
The white portion of teh tough outer
layer of the eyeball
Sebaceous gland
Oil-forming glands found all over the body,
especially on the face and neck
...
128
Seondary active transport
Active transport that releies on an established
concentration gradient, typically set up by a primary
active transporter
...
Secondary immune response
A subsequent immune response to previously
encountered antigen that results in antibody
production and T cell activation
...
THis is
not long enough for the infection to become
established, and symptoms do not appear, thus the
person is said to be "immune" to that particular
antigen
...
The secondary
oocyte (along with some follicular cells) is released
from the ovary during ovulation
...
Secondary spermatocytes are
ready to enter meiosis II
...
In
males the secondary sex characteristics include
enlargement and maturation of the genitalia, growth
of facial, body, and pubic hair, increased muscle
mass, and lowering of the voice
...
129
Second Law of Thermodynamics
The entropy (disorder) of the universe (or system)
tends to increase
...
Secretin
A hormone secreted by the small intestine
(duodenum) in response to low pH (e
...
, from
stomach acid)
...
Secretion
(1) The secretion of useful substances from a cell,
either into the blood (endocrine secretin) or into a
cavity or onto the body surface (exocrine secretion)
...
Secretion increases the rate at which substances can
be removed from the body
...
The secretory phase is
primarily under the controll of progestone and
estrogen (secreted from the copus luteum during
this time period), adn typically lasts from day 15 to
day 28 of the menstrual cycle
...
Semen is very
nourishing for sperm
...
Semiconservative replication
DNA replication in which each of the parental
strands is read to make a complementary daughter
strand, ethus each new DNa molecule is composed of
half the parental molecule paired with a newly
synthesized strand
...
The pulmonary semilunar valve
separates the right ventricle from the pulmonary
artery, and the aortic semilunar valve separates left
ventricle from the aorta
...
Seminal vesicles
Paired glands found on the posterior external wall of
the bladder in males
...
131
Seminiferous tubules
Small convoluted tubules in the testes where
spermatogenesis takes place
...
Serum
Plasma with the *clotting factors removed*
...
Sex-linked rait
A triat determined by a gen on either the X or Y
chromosomes (the sex chromosomes)
...
132
Signal recognition particle (SRP)
A cytoplasmic protein that recognizes the signal
sequences of proteins destined to be translated at the
rough ER
...
Signal sequences are found on
membrane-boudn proteins, secreted proteins, and
proteins destined for other organelles
...
Typically
this activates seond messenger pathways
...
Simple diffsuion
The movement of a hydrophobic molecule across the
plasma membrane of cell, down its concentration
gradient
...
133
Single strand binding proteins
Proteins that bind to and stabilize the signle strands
of DNA exposed when helicase unwinds the double
helix in preparation for replication
...
Sister chromatid
Identical copies of a chromosome, produced during
DNA replication and held together at the centromere
Sister chromatids are separated during anaphase of
mitosis
...
SKeletal
muscle is striated multinucleate, and under
voluntary control
...
It is a series of four repeated
steps: (1) myosin binds actin, (2) myosin pull actin
toward the center of the sarcomere (3) myosin
releases actin, and (4) myosin resets to its
high-energy conformation
...
This results in the
hardening of the zona pellucida and its separation
from the surface of the egg, preventing the entry of
more than one sperm into the egg
...
It is subdivided into
three regions: the duodenum, the jejunum, and the
ileum
...
Smooth muscle
Muscle tissue found in the walls of hollow organs,
e
...
, blood vessels, the digestive tract, the uterus, etc
...
Soma
The cell body of a neuron
...
Spatial summation
Integration by a postsynaptic neuron of inputs
(EPSPs and IPSPs) from multiple sources
...
Spermatids undergo significant physical changes
to become mature sperm (spermatozoa)
...
Spermatogenesis results in the production of four
mature gametes (sperm) from a single precursor
cell (spermatogonium)
...
Spermatogonium
A diploid cell that can undergo mitosis to form
more spermatogonium, and can also be triggered
to undergo meiosis to form sperm
...
Sphincter of Oddi
The valvecontrolling release of bile and pancreatic
juice into the bloodstream
...
THe spleen has four functions: (1) it
filters antigen from the blood (2) it is the site of B
cell maturation, (3) it stors blood, and (4) it destroys
old red blood cells
...
SPlicing of transcripts can
be different in different tissues
...
Spongy gone is filed with red bone
marrow, important in blood cell formation
...
Steroid hormone
A hormone derived from cholesterol
...
Once this steroid
binds to its receptor, the receptor-steroid complex
acts to regulate transcription in the nucleus
...
Limited digestion occurs in the somach,
and it has the lowest pH in the body (1-2)
...
The stop codons are UAA, UGA, and UAG
...
Stroke volume
The volume of blood pumped out the heart in a
single contraction
...
Substrate(s)
The reactants in an enzyme-catalyzed reaction
...
Sudoriferous gland
A sweat gland located in the dermis of the skin
...
139
Summation
(1) The integration of input (EPSPs and IPSPs) from
many presynaptic neruons by a single postsynaptic
neuron, either temporaly or spatially
...
(2) The integration of single muscle
twitches into a sustained contraction (tetany)
...
Surfactant
An amphipathic molecule secreted by cells in the
alveoli (type 2 alveolar cells) tha reducs surface
tension on the inside of the alveolar walls
...
Sympathic nervous
system
The division of the autonomic nervous system
known as the "fright or flight" system
...
It causes a general
decrease in digestive activity
...
Symporter
A carrier protein that transports two molecules
across the plasma membrane in the same direction
...
140
Synapse
A neuron-to-neuron, neuron-to-organ, or muscle to
cell-to-muscle cell junction
...
Synaptic cleft
A microscopic space between the axon of one neuron
and the cell body or dendrites of a secon neruon, or
between the axon of a neuron and an organ
...
g
...
Syngergist
Something that works together with another thing to
augment the the second thing's activity
...
An enzyme that helps another
enzyme is a synergist
...
Systemic circulation
The flow of blood from the heart, through the body
(not including the lungs), and back to the heart
...
Systolic pressure
The pressure measured in the arteries during
contraction of the ventricles (during systole)
...
The major subtypes of T cells
are the helper T cells (CD4) and the killer T cells
(CD8, or cytotoxic T cells)
...
Killer T cells destroy abnormal self-cells (e
...
, cancer
cells) or infected cells
...
Telomere
A specialized region at the ends of eukaryotic
chromosmes that contains several repeats of a
particular DNA sequence
...
In cells that lack
telomerase, the telomeres slowly degrade with each
round of DNA replication (as the RNA primer, is not
replaced and the 5' of the new DNA would not exist);
this is though to contribute to the eventual death of
the cell
...
During
telophase the nuclear envelope reforms,
chromosomes decondense, and the mitotic spindle is
disassembled
...
Telophase I is identical to
mitotic telophase, except that the number of
chromosoms is now reduced by half
...
Note however,
that the chromosomes are still replicated, and the
sister chromatids must still be separated during
meiosis II
...
Telophase II
is identical to mitotic telophase, except that the
number of chromosomes was reduced by half during
meiosis
...
143
Temporal summation
Summation by a postsynaptic cell of input (EPSPs or
IPSPs) from a single source over time
...
Testcross
A genetic cross between an organism displaying a
recessive phenotype (homozygous recessive) and an
organism displaying a dominant phenotype (for whic
the genotype is unknown), done to determine the
unknown genotype
...
The testes are
suspended outside the body cavity in the scrotum
and have two functions (1) produce sperm, and (2)
secrete testosterone
...
Testosterone is a steroid hormone produced and
secreted by the interstitial cells of the testes
...
144
Tetanus
A smooth sustained muscle contraction, such as
occurs in skeletal muscle when stimulation
frequency is high enough (this is the normal type of
contraction exhibited by skeletal muscle)
...
Tetrads form during prophase I of meiosis so that
homologous chromosomes can exchange DNA in a
process known as 'crossing over
...
the thalamus acts as a relay station and major
integrating area for sensory impulses
...
Thecal cells help produce the
estrogen secreted from the follicle during the first
phase of the ovarian cycle
...
145
Theta replication
DNA replication in prokaryotes, so named because
as replication proceeds around the single, circular
chromosome, it takes on the appearnce of the Greek
letter theta
...
The
myosin head groups attach to the thick filaments and
pull the toward the center of the sarcomere during
muscle contraction
...
Thin
filaments are attached to teh Z lines of the sarcomers
and slide over thick filaments during muscle
contraction
...
Thrombi are dangerous they can break free
and begin travelin in the bloodstream (become an
embolus)
...
A
brain embolism cna lead to stroke, a heart embolism
to a heart attack, and a pulmonary embolism to
respiratory failure
...
Thymine is a pyrimidine; it pairs with adenine
...
THe
thymus is the site of T cell maturation and is larger
in children and adolescents
...
Thyroxine
Also called thryoid hormone, thyroxine is produced
and secreted by follicle cells in the thyroid gland
...
Tidal volume
The volume of air inhaled and exhaled in a normla,
resting breath, typically about 500 mL
...
Tight
junctions are found between the epithelial cells
lining the intestines and between the cells forming
the capillaries in the brain (the blood-brain barrier)
...
Tonsils
Paired masses of lymphatic tissue near the back of
the throat that help trap inhaled or swallowed
pathogens
...
Total lung capacity
The maximal volume of air that the lungs can
contain
...
Totipotent
Having the ability to become anything; a zygote is
totipotent
...
The trachea is made of alternating rings of
cartilage and connective tissue
...
Transition mutation
A point mutation in which a pyrimidine is
susbstituted for a pyrimidine, or a purine is
substituted for a purine
...
Protein translation takes place on
a ribosome
...
Transversion mutation
A point mutation in which a pyrimidine is substitued
for a purine, or vice versa
...
tRNA loading
The attachment of an amino acid to a tRNA (not that
this a specific interaction)
...
Trophoblast
The outer ring of cells of a blastocyst
...
150
Tropic hormone
A hormone tha tcontrols the release
of another hormone
...
In the absence of Ca2+,
tropomyosin covers the myosin-binding sites on
actin and prevents muscle contraction
...
Troponin
A globular protein that ssociated with tropomyosin
as part of the thin filament of the sarcomere
...
Trypsin
The main protease secreted by the pancreas; trypsin
is activated (from trypsinogen) by enterokinase, and
subsequently activates other pancreatic enzymes
...
These
invaginations allow depolarization of the membrane
to quickly penetrate to the interior of the cell
...
The tympanic membrane is also known
as the eardrum
...
The umbilical cord contains fetal arteries (carry
blood toward the placenta) and veins (carry blood
away from the placenta)
...
Uniporter
A carrier protein that transports a single molecule
across the plasma membrane
...
Because this person's
red blood cells possess all of the typical blood surface
proteins, they will not display an immune reaction if
transfused with any of the other blood types
...
Because this person's
red blood cells possess none of the typical blood
suface proteins, they cannot initiate an immune
reaction in a recipient
...
The promoter and start
sites are upstream
...
Uracil
is pyrimidine; it pairs with adnenine
...
Ureters
The tubes that carry urine from the
kindeys to the bladder
...
In males it also carries semen
and sperm during ejaculation
...
It has an internal part made of smooth
muscle (thus involuntary) and an external part made
of skeletal muscle (thus voluntary)
...
This is also the normal site of
fertilization
...
Uterus
The muscular femal organ, in which a baby develops
during pregnancy
...
Typically the antigens are
those normally associated with pathogens, thus if the
live pathogen is encountered in the future, the
seconday immune response can be initiated,
preventing infection and symptoms
...
Vagal tone reduces the intrinsic firing
rate of teh SA node from 120 beats/minute to around
80 beats/minute
...
Vagus nerves
Cranial nerve pair X
...
They are especially important in transmitting
parasympathetic input to the heart and digestive
smooth muscle
...
The vasa recta reclaims reabsorbed
substances, such as water and sodium ions
...
Muscular contractions of
the vas deferns during ejaculation ehp propel the
sperm outward
...
Vein
A blood vessel that carries blood toward the heart
chambers
...
155
Vena cava
One of two large vessels (superior and inferior) that
return deoxygenated blood to the right atrium of the
heart
...
Ventricle
One of two large chambers in the heart
...
The right ventricle has
thing walls and pumps deoxygenated blood to the
lungs through the pulmonary artery
...
Vestibular glands
Paired glands near the posterior side of the vaginal
that secrete an alkaline mucus upon sexual arousal
...
Villi
(Singular:villus)
...
156
Virus
A nonliving, intracellular parasite
...
Vital capacity
The maximum amount of air that can be forcibly
exhaled from the lungs after filling them to their
maximum level, typically about 4500 mL
Vitamin
One of several different nutrietns that must be
consumed in the diet, and generally not synthesized
in the body
...
Vitreous humor
A thick, gelatinous fluid found in the posterior
segment of the eye (between the lens and the retina)
...
Voltage-gated ion channel
An ion channel that is oepend or closed based on the
electrical potential across the plasma membrane
...
Examples are the Na+ and K+
voltage-gated channels involved in the action
potential of neurons
...
Yolk sac
An embryonic structure particularly important in
egg-laying animals because it contains the yolk, the
only source of nutrients for the embryo developing
inside the egg
...
Z lines
The ends of a
saromere
...
158
Zygote
A diploid cell formed by the fusion of two gametes
during sexual reproduction
...
)
159