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Title: Final study guide for Anatomy I
Description: SMU 2441 - first semester of sequential anatomy classes Chapters include: chemical organization, cellular organization, tissue organization, Integumentary system, Osseous tissue, axial skeleton, appendicular skeleton, joints, skeletal muscle tissue, nervous tissue and the autonomic nervous system
Description: SMU 2441 - first semester of sequential anatomy classes Chapters include: chemical organization, cellular organization, tissue organization, Integumentary system, Osseous tissue, axial skeleton, appendicular skeleton, joints, skeletal muscle tissue, nervous tissue and the autonomic nervous system
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Ariana Dubelko
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APSM 2441 Final Exam Review
Chapter 1
o Tissue: groups of cells that work together to perform a particular function; 4 types
§ Epithelial Tissue
§ Muscular Tissue
§ Connective Tissue
§ Nervous Tissue
o Organ: different types of tissues joined together to perform specific functions; usually have
recognizable shapes
§ Ex
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Digestive proteins split proteins into amino acids
o 6 essential life processes
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Responsiveness: ability to detect changes in the environment and make an appropriate
response à CNS detects raised blood pressure, regulates it
3
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Growth: increase in size due to cell development and differentiation à bone growth,
working out to gain muscle
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Reproduction à fertilization of an egg by a sperm; formation of new cells in order to
repair, replace, or grow new tissue à having a baby, formation of new bone during
appositional growth
o Homeostasis: a condition of equilibrium in the body’s internal environment; dynamic or you would
be dead
o Feedback system: Stimulus is detected by the receptor à sends info to the control center à
control center decides what to do with stimulus, sends to effector
o Negative Feedback system: reverses a change in a controlled condition
o Ex
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Normal child birth
o Stretching of cervix = stimulus
o Nerve cells (receptors) receive stimulus
o Send to brain = control center
o Brain interprets and sends info to muscles in uterus to contract more = effector
o Result is increased stretching of cervix
Chapter 2: Chemical Organization
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Three states of matter
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Blood
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Oxygen and Carbon Dioxide
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Bone
Anion = negatively charged ion à Chloride (Cl-‐)
Cation = positively charged ion à Calcium (Ca2+)
Endergonic reaction = releases more energy than it absorbs
o Build body structures, move substances in and out of cells
Exergonic reaction = absorbs more energy than it releases
o Occur as nutrients are broken down à glucose to ATP
Inorganic Compound = usually lack carbon, structurally simple
o Water, salts, acids, bases, carbon dioxide, carbonic acid
o Water is most abundant inorganic compound in human body (55-‐60% of adult body mass)
Organic Compound = always contain carbon, usually contain hydrogen, always have covalent
bonds; most are large molecules; makeup 38-‐43% of human body
o Major organic compounds in human body:
§ carbohydrates, lipids, proteins
Carbohydrates = function as a source of chemical energy for generating ATP needed to drive
metabolic reactions
Monosacchrides – simple sugars; 5 ring hexos; only absorbable form of carbohydrate
o Glucose (most utilized for producing energy), fructose, galactose
Disacchrides – 2 monosacchrides (glucose + 1 more)
o Sucrose = glucose + fructose
o Lactose = glucose + galactose
o Maltose = glucose + glucose
Polysacchrides – chain of monosacchrides
o Starches à only found in plants
o Cellulose (fiber) à we can’t digest it
o Glycogen (in animals) à chain of glucose molecules stored in muscles and liver; easiest
form of energy
Lipids = fatty acids, triglycerides, phospholipids, steroids; hydrophobic
o Fatty acids
§ Saturated = solid at room temperature, contain only single covalent bonds à
saturated with hydrogen atoms
§ Unsaturated à liquid at room temp, contain one or more double covalent bonds
• Mono = one kink
• Poly = 2 kinks
• Essential Fatty acids cannot be made by the human body but we need them
to survive à omega 3, omega 6, cis-‐fatty acids
o Decrease bone loss, reduce arthritis, wound healing, improve skin
healing, improve mental function
o Lower LDL, raise HDL
o Triglyceride – one glycerol + 3 Fatty acids (FA are simplest lipid)
§ How body stores fat; used for protection, insulation, energy storage
o Phospholipid – structural component of cell membrane (phospholipid bilayer)
§ Polar head that dissolves in water (hydrophilic head), non-‐polar tail that does not
(hydrophobic tail)
o Lipoprotein – compound lipid, transport lipids in blood, carry triglycerides and cholesterol
to tissues and remove excess cholesterol from bloodà lipid molecules joining with
hydrophilic protein molecules, become soluble because the proteins are on the outside and
lipids are on the inside
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High density lipoproteins = good cholesterol, contributes to health of cells, keeps
LDLs from sticking
§ Low density lipoproteins = bad cholesterol, clogs arteries
o Steroids
§ Cholesterol – needed for cell membrane structure
§ Estrogen
§ Testosterone
§ Cortisol
§ Bile salts
§ Vitamin D
o Trans-‐fatty acids increase LDL, reduce HDL, increase risk of heart disease
o Enzyme à special proteins that catalyze metabolic reactions in all living cells
o Substrate = substance upon which an enzyme has its effect
o Enzymes (catalysts) speed up chemincal reactions by increasing frequency of collisions,
properly orienting molecules, and / or lowering activation energy
o Concentration of reactants, temperature, and presence of a catalyst increase likelihood of reaction
occurring
o Free radicals à an electrically charged oxygen atom with an unpaired electron, destroys cells
looking for an electron to pair with
o Radiation, inflammation, metabolism, smoking, pollution, UV light, exercise all contribute
to free radical production
o Free radicals are linked to cancer, alzheimers, diabetes, arthritis, aging deterioration
o Antioxidants are sent out to reduce free radicals; superoxide dismutase (in body), vitamin
C, dark chocolate, berries
Chapter 3: Cellular Organization
o Three main parts of cells:
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Most plasma membranes include specific channels for several
common ions
o Carrier (Integral) – transporter; transports specific substances across
membrane by changing shape
o Enzyme (integral and peripheral) – catalyze reactions in/out of cell
o Linker
o Identity Markers (glycoprotein) – distinguishes your cells from anyone
else’s; important class markers are major histocompatibility proteins
o Receptors *
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Nucleus – genetic library of cell
o Osmosis = diffusion in which there is a net movement of a solvent through a selectively permeable
membrane; passive process; water moves by osmosis across plasma membranes from an area of
lower solute concentration to higher solute concentration
o Move via simple diffusion OR through aquaporins
o If cell is in hypertonic solution, net movement of water is out of the cell (crenation)
o Hypotonic solution, net movement of water is into the cell (hemolysis)
o Isotonic solution, no net water movement out of cells
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Electrochemical gradient = Concentration gradients – dif in concentration of a chemical between 2
regions; Electrical gradients – dif in electrical charges between 2 regions
o Help move substances across plasma membrane
o Down concentration gradient = passive process
§ Facilitated diffusion = passive; carrier moves solute down its concentration
gradient across plasma membrane, no energy required
o Active process = cellular energy is used to drive substance against its concentration
gradient
Active Transport
o Primary active transport: energy derived from hydrolysis of ATP changes shape of a carrier
protein, which pumps a substance across plasma membrane
§ Ex
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Sodium-‐glucose symporter
§ Antiporters = moving two substances in opposite directions across membrane; ex
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Tight junctions – weblike strands of transmembrane proteins that fuse together the outer
surfaces of adjacent plasma membranes to seal off passageways between adjacent cells à
stomach or bladder
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Desmosomes – contain plaque and cadherins, weld-‐like junctions that prevent cells from
separating under tension and contraction à epidermis and cardiac muscle cells
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Gap junctions – membrane proteins called connexins form fluid filled tunnels that connect
neighboring cells; plasma membranes of gap junctions are not fused together; ions and
small molecules can diffuse from one cell to another; allow cells to communicate with one
another à nervous system, cardiac muscles, cornea of eye
o Epithelial Cells
o Apical surface = free surface, may contain scilia / microvilli
o Lateral surface = face adjacent cells on either side, may contain junctions
o Basal surface = adhere to extracellular materials (basement membrane)
o Basement membrane = thin extracellular layer formed by:
§ Basal lamina = closer to and secreted by epithelial cells
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§ Reticular lamina = closer to connective tissue
2 types
§ covering and lining epithelium à outer covering of skin, inner lining of internal
organs
§ glandular epithelium à makes up secreting portion of glands
• endocrine glands – secrete hormones into blood, no duct
• exocrine glands – secrete products into a duct that are then released onto
surface of or into lumen of organ
Arrangement of Epithelial cells
o Simple epithelium – one layer; functions in diffusion, filtration, secretion, absorption; all
cells in contact with basement membrane
o Pseudostratified epithelium – appears to have layers because nuclei are at different levels
and not all cells reach apical surface but all cells touch basement membrane
§ Cells that do not reach apical surface are goblet cells and secrete mucous
§ Cells that reach apical surface may have cilia
o Stratified epithelium – two or more layers that protect underlying tissues from wear and
tear
Shape of Epithelial cells
o Squamous – flat and wide, thin, allows for rapid passage of substances
o Cuboidal – cube shaped, function in secretion and absorption, may have microvilli
o Columnar – taller than they are wide, protect underlying tissue, specialized for secretion
and absorption, apical surface may have cilia or microvilli
o *Transitional – change from squamous to cuboidal (bladder)
Epithelial Tissues: avascular, innervated, high regeneration rate for renewing / repairing tissue
o Simple epithelium:
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Lungs
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Simple cuboidal: lines tubules of kidneys and some glands; function is secretion and
absorption
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Nonciliated = gastrointestinal tract
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Pseudostratified columnar: respiratory tract, ciliated secretes mucous to trap
particles
o Stratified epithelium
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Keratinized location = epidermis, non keratinized = mouth
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Stratified columnar: protection and secretion; found in salivary glands
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Tissue; epithelial layer has tight junctions
o Cutaneous membrane: skin!
o Serous Membrane: visceral and parietal layers (parietal connects to areolar connective tissue);
lines pericardium, peritoneum, pleura
Chapter 5: Integumentary System
o Functions of integumentary system:
o Protection
§ Sebum (oil) – secreted by sebaceous glands – prevents bacteria and drying out of
hair and skin
§ Sweat (acidic pH0 – secreted by sudoriferous glands, kills microbes
§ Melanin – shields keratinocytes from UV damage
§ Keratin – protects tissues from microbes, abrasion, heat, chemicals
§ Lipids – lamellar granules prevent water evaporation from skin, prevent entry of
water on skin surface
§ Langerhans cells – signal immune system to attack invader
o Thermoregulation
§ Cold stress – constriction of blood vessels in dermis reduce heat loss, decrease
sweat rate
§ Heat stress – increased sweating, dilation of blood vessels in skin increase amount
of heat loss from the body
o Sensory perceptions
§ Meisner’s corpuscles – touch
§ Pacinian corpuscles – pressure
o Synthesis of Vitamin D
§ UV rays stimulate vit d synthesis, enzymes in liver and kidneys convert Vit D to
calcitrol which aids in calcium absorption; need 10-‐15 mins of sunlight 2x per week
o Emotional Expression
o Epidermis: resists damage, protects underlying tissues
o Cells:
§ Keratinocytes – 90% of epidermal cells, produce keratin (protects skin from
abrasions, heat, microbes, chemicals; secrete lamellar granules
§ Melanocytes – produce melanin that is present in keratinocytes to protect the
nucleus, contributes to skin color, absorbs UV light; similar number in each person
but they produce a different amount of pigment
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Freckles = clusters of concentrated melanin triggered by exposure to
sunlight; genetic trait
• Moles = nevi / birthmarks, lesions/overgrowth of melanocytes of the skin
o Malignant melanoma is cancer of melanocytes
• Albinism – dysfunction in the enzyme that produces melanin, absence of
pigment in skin, hair, eyes
• Vitiligo – absence of melanocytes in an area resulting in depigmentation;
unknown genetic factor coupled with autoimmune disease
§ Langerhans cells – immune response, easily damaged by UV light which reduces
their ability to destroy invading microbes
§ Merkel cells – detect touch sensations; located in stratum basale layer of epidermis
o Layers:
§ Stratum corneum – flat, dead keratinocytes that contain mostly keratin
§ Stratum lucidum – only in skin of fingertips, palms, soles; flat dead keratinocytes
with large amount of keratin à IN THICK SKIN
§ Stratum granulosum – flattened keratinocytes that are beginning to degenerate;
layer that secretes lamellar granules
§ Stratum spinosum – keratinocytes with bundles of keratin; contains melanocytes
§ Stratum basale – deepest layer, composed of cuboidal / columnar keratinocytes;
stem cells undergo cell division to produce new keratinocytes; melanocytes and
tactile epithelial cells associated w tactile discs are scattered among keratinocytes
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Spinal cord
o Movement – muscle attach to bones, move body
o Mineral homeostasis – bone tissue is made up mostly of calcium and phosphorus
o Blood cell production – red bone marrow produces red blood cells, white blood cells, and
platelets = hemopoiesis
§ Fetus – all marrow is red
o Triglyceride storage – yellow bone marrow is mostly made of adipose cells, store
triglycerides as a potential energy reserve
o Structure of long bone:
o Diaphysis – middle / long portion of long bone
o Metaphysis – between epiphysis and diaphysis
o Epiphysis – proximal and distal ends of long bone, covered by articular cartilage (hyaline),
composed of spongy bone
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Periosteum – membrane surrounding entire bone
§ Dense irregular connective tissue, highly vascularized and highly innervated
§ Contains osteoblasts that promote appositional bone growth
§ Assists with fracture repair
§ Attachment point for tendons and ligaments
o Endosteum – lines medullary cavity
o Medullary cavity – where yellow marrow is housed, highly vascularized, minimizes weight
of bone
o Epiphyseal plate – hyaline cartilage in adolescents, cellular division at the growth plate
causes elongation of the bone at each end
§ Epiphyseal line when growth stops
o Articular cartilage – ECM is composed of gel like ground substance and collagen fibers;
chondrocytes in lacunae, lacks perichondrium and blood supply
Process of Longitudinal / Interstitial growth at epiphyseal plate (4 zones):
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Zone of proliferating cartilage à chondrocytes are slightly larger and arranged like stacks
of coins; undergo interstitial growth as they divide and secrete ECM, divide to replace dead
chondrocytes at diaphyseal side of plate
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Zone of calcified cartilage à only a few cells thick, consists of dead chondrocytes (ECM
around them has calcified), osteoclasts dissolve calcified cartilage, osteoblasts and
capillaries from diaphysis invade, osteoblasts secrete ECM and this zone becomes new
diaphysis (bone)
Cells of Osseous Tissue
o Osteoprogenitor cells – unspecialized bone stem cells derived from mesenchyme, only
bone cell to undergo cell division, resulting cells develop into osteoblasts; found in
periosteum/endosteum
o Osteoblasts – bone builders (deposition); secrete ECM; initiate calcification; become
osteocytes when they mature
o Osteocytes – mature bone cells, main cell in bone tissue, maintains daily metabolism of
tissue
o Osteoclasts – large, derived from WBC, concentrated in endosteum, breaks down bone
(resorption)
o Chondrocytes – cartilage cells that monitor cartilage tissue
o Chondroblast – cartilage cells that secrete ECM
Functions of Osseous Tissue
o Osteons – composed of repeating structural units of concentric lamellae arranged around a
central canal; in compact bone
o Lacunae – spaces between concentric lamellae that contain osteocytes; little lakes
o Canaliculi – projections from the lacunae
o Concentric lamellae – circular plates of mineralized ECM of increasing diameter
surrounding a smell network of blood vessels and nerves
o Interstitial lamellae – space between neighboring osteons
o Central canal – contains blood vessels and nerves
o Trabeculae – in spongy bone, irregular patterns of lamellae, red bone marrow is within the
spaces
o Factors that effect bone remodeling:
§ Minerals à calcium and phosphorus are needed
§ Vitamins à vitamin A stimulates osteoblast activity, vit C is needed for synthesis of
bone protein
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Hormones à HgH, Thyroid hormones, and insulin like growth factors stimulate
bone growth
§ Exerciseà stressed bone remodles stronger
§ Braces à stress bone that forms sockets
Appositional Bone Growth
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Osteocyte ridges fuse together forming tunnel and enclosing blood vessel; former
periosteum becomes endosteum that lines tunnel
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Osteoblasts under periosteum build new circumfrential lamellae making bone even thicker,
additional blood vessels become enclosed and processes repeats
Bone Remodeling – replacement of old bone tissue with new bone tissue
o Resorption – removal of minerals and collagen fibers from bone tissue (osteoclasts)
o Deposition – addition of mineral and collagen fibers to bone (osteoblasts)
o 5% is being remodeled at any given moment
o Compact bone: 4% per year
o Spongy bone: 20% per year (distal part of femur about ever 2-‐4 months)
Hardness of bone (compression ability) – crystallized minerals
Flexibility of bone (tensile strength) – collagen fibers
Parathyroid Hormone: regulates free Ca2+ concentration in blood; secreted when you have low
plasma calcium content
o Stimulus à low plasma Ca2+
o Receptor à PTH gland cells detect low Ca2+ concentration
o Control center à DNA in PTH gland cells (PTH gene turned on and PTH is secreted)
o Effectors à
§ Bone: stimulates osteoclast formation, number, and activity
§ Kidneys: decrease loss of Ca2+ in urine, activate Vitamin D which stimulates
calcitrol synthesis and increases Ca2+ absorption
§ GI tract à calcitrol promotes Ca2+ absorption from foods
Calcitonin: secreted when you have high Ca2+ plasma levels in blood
o Stimulus à high plasma Ca2+
o Receptor à parafollicular cells in thyroid gland detect high levels
o Control center à DNA in parafollicular cells
§ Calcitonin is secreted by thyroid gland
o Effectors à
§ Bone à inhibits osteoclast activity, promotes bone deposition
Osteoporosis: bone resorption > deposition
o 80% patients are female
o Risk factors: sedentary lifestyle, poor diet, alcohol and drug use
Bone related conditions:
o Osteomalacia – inadequate calcification in adults; pain in bones and frequent fractures
o Rickets – inadequate calcification in immature bone; growing bones become rubbery
o Giantism – oversecretion of hGH during childhood
o Acromegaly – too much growth hormone is secreted after closure of epiphyseal plates; too
much new tissue is formed and bones become heavy and thick
o Osteoarthritis -‐-‐
o Dwarfism – undersecretion of hGH during childhood; normal sized head and torso and
small but proportionate limbs
Calcification = the hardening of bones
Tumor of Parathyroid Gland
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Hypersecretion of PTH would result in increased osteoclast activity because the PTH
signals that the body needs more calcium
Bones would experience higher levels of resorption
Too much calcium in the body could result in seizures / sustained muscle contractions
Calcitonin would be secreted if body could detect high levels of Ca2+
Chapter 7: Axial Skeleton
o Five types of bones:
o Long bone – greater length than width, absorbs stress of body’s weight, mostly compact
bone but spongy in epiphysis; contain medullary cavity
§ Femur
o Short bone – cube shaped, spongy bone covered in layer of compact bone
§ Trapezoid (wrist bones)
o Flat bone – thin and composed of two plated of compact bone tissue enclosing layer of
spongy bone tissue; protection
§ Cranial bones; sternum
o Irregular bone – complex shapes, vary in amount of spongy and compact bone
§ Hip bones, vertebrae
o Sesamoid bone – develop in tendons where there is a lot of friction, protect tendons from
excessive wear by acting as pulley
§ Patella
o Curves of vertebrae
o Cervical (7) – develops when infant can hold up head
o Thoracic (12) – primary curve in fetus
o Lumbar (5) – develops when child can sit, stand up
o Sacral (5 fused) – primary curve in fetus
o Abnormal curvature of vertebra
o Scoliosis – lateral curving
o Kyphosis – increased thoracic curve (osteoporosis)
o Lordosis – increased lumbar curve (belly out)
o Axial skeleton – skull, thorax, vertebral column (80 bones)
o Appendicular skeleton – bones of all appendages (206 bones)
o Paranasal sinuses – mucous membranes produce mucous to moisten and clean inhaled air
o Sinusitis = inflammation of the mucous membranes
o Nasal Septum – perpendicular plate of ethmoid bone and septal cartilage
o Deviated septum = misalignment of the septum
o Broken nose = usually perp
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CT (coronal suture)
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Syndesmosis –anmphiarthrosis, band or ligament, greater distance between the
articulating surfaces and more dense irregular connective tissue than in suture
(tibiofibular joint)
§ Interosseous Membranes – amphiarthrosis, sheet of dense irregular CT that binds
neighboring long bones (radius and ulna; tibia and fibula)
o Cartilaginous – no synovial cavity, bones held together by cartilage
§ Synchondroses – synathrosis; cartilaginous joint where connecting material is
hyaline cartilage (epiphyseal plate = syntosis)
§ Symphysis – amphiarthrosis; ends of articulating bones are covered with hyaline,
but disc of fibrocartilage connects bones; all occur at midline of body (pubic
symphysis)
o Synovial – (diarthrosis) bones forming the joint have a synovial cavity and are united by
dense irregular connective tissue of an articular capsule and accessory ligaments
§ Epiphysis of articulating bones covered in articular cartilage
§ Articular capsule: fibrous membrane (ligament) and synovial membrane, filled w
synovial fluid
§ Articular fat pads for cushioning, synovial fluid for shock absorption, lubrication,
oxygen and nutrient supply to chondrocytes, friction reduction
Functional Classification of Joints
o Synarthrosis – immovable joint
§ Syntosis – bony joint (some sutures)
o Amphiarthrosis – slightly movable joint
o Diarthrosis – A freely movable joint
Types of Synovial Joints
o Plane joints – back and forth, side to side movement; biaxial à tarsals in foot
o Hinge joints – open and closing motion; uniaxial à humerus and ulna at trochlear notch
o Pivot joints – rotation around longitudinal axis; uniaxial à head of radius and radial notch
of ulna
o Condyloid joints – flexion and extension, abduction and adduction; biaxial à wrist
o Saddle joints – flexion and extension, abduction and adduction; biaxial à between wrist
and thumb
o Ball and Socket joints – flexion and extension, abduction and adduction, rotation; triaxial;
head of femur and acetabulum of hip bone
Movements:
o Flexion – elbow
o Extension – arm straight down
o Hyperextension – arm behind midline (from standing)
o Adduction – toward midline
o Abduction – away from midline
o Circumduction – distal end of body part in a circle
o Dorsiflexion – ankle joint, foot up
o Plantar flexion – ankle joint, point toes
o Lateral flexion – leaning to the side; intervertebral joints
o Inversion – pressure on outside of foot (intertarsal joints); supination
o Eversion – pressure on big toe; pronation
o Opposition – carpometacarpal joint; fingertips touching
o Pronation – posterior of palm (radioulnar joint)
o Supination – anterior of palm
o Retraction – temporomandibular joint
Factors that affect range of motion:
o Structure / shape of articulating bones
o Strength and tension of joint ligaments
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Arrangement and tension of muscles
Contact of soft tissues
Hormones
Disuse
Chapter 10: Skeletal Muscle Tissue
o Characteristics of Muscle Tissue
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Contractibility: can shorten in length
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Elasticity: can return to original shape after being stretched
o Types of muscle tissue
o Skeletal
o Cardiac
o Smooth
o Functions of Muscle Tissue
o Produce body movements – whole body or localized
o Stabilizing body position – maintain posture
o Moving substances within the body – smooth and cardiac muscle
o Generating heat (thermogenesis) – muscle contraction (skeletal and involuntary) generates
heat
o Structure of a muscle
o Epimysium: membrane surrounding whole muscle
o Perimysium: membrane surrounding fascicle
o Endomysium: membrane surrounding individual muscle fibers
o Fascicle: group of muscle fibers
o Myofibril: contractile organelles of skeletal muscles that make up the muscle fiber cell,
contain chains of sarcomeres
o Myofilament: contractile proteins within myofibrils, thick or thin
o Sarcolemma: plasma membrane of muscle cell
o Sarcoplasm: cytoplasm of muscle fiber
o Sarcoplasmic Reticulum: membranous sacs that release and reuptake calcium during
contraction
o T-‐tubules: invaginations in the sarcolemma where action potential travels down cell
o Thick filament: myosin
o Thin filament: actin
o Satellite cells: help repair muscle cells
o Structure of a Sarcomere
o Contractile proteins: myosin (thick) and actin (thin)
o Regulatory proteins: turn contractions on and off
§ Troponin – pulls tropomyosin away
§ Tropomyosin – covers myosin binding site
o Structural proteins: provide sarcomere alignment, elasticity, extensibility
§ Titin –
§ Alpha-‐actinin – binds actin to titin
§ Myomesin – m line proteins bind adjacent thick filaments together
§ Nebulin – binds actin to z discs (wraps around actin filament)
§ Dystrophin – links thin filament to sarcolemma
o Z discs – narrow plate shaped regions that separate one sarcomere from next
o A band – dark, middle part of sarcomere that extends entire length of thick filaments and
includes parts of thin filaments that overlap thick
Ariana Dubelko
I band – lighter, less dense area of sarcomere that contains remainder of thin filaments and
no thick filaments; Z disc passes through center
o H zone – narrow region in center of each A band, contains thick filaments, no thin
o M line – region in center of H zone that contains proteins that hold thick filaments together
at center of sarcomere
Sliding filament mechanism:
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Calcium binds troponin
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Opening of myosin binding sites and the myosin heads are free to bind
Contraction / cross-‐bridge cycle:
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Myosin heads bind to actin, forming cross-‐bridges
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As myosin heads bind ATP, cross-‐bridges detach from actin
Excitation-‐Contraction coupling – involves events at junction between motor neuron and skeletal
muscle fiber
o Nerve action potential travels down axon of nerve activating voltage gated calcium
channel
o Triggers release of ACh from synaptic vesicle
o Ach activates ligand-‐gated sodium channels in junctional folds of motor end plate
o Create a muscle action potential
o Travels down sarcolemma and T tubules
o Opens Ca2+ release from SR
o Calcium bins to troponin, exposes binding site for myosin on actin
o Contraction occurs
Muscle relaxation:
o Ca2+ release channels in SR close, active transport pumps use ATP to bring back Ca2+
o Troponin-‐tropomyosin complex slides back to cover binding site
o Muscle relaxes
Acetylcholine-‐esterase degrades Ach
Length-‐tension relationship = how forceful a muscle contraction can be depends on the length of
the sarcomere before the contraction begins
o Maximum tension occurs when zone of overlap between thick and thin filament extend
from edge of H zone to end of thick filament
o Very close to resting length is optimal
o Stretched too long: fewer myosin heads can make contact w actin
o Shortened length: tension decreases because fewer myosin heads are making contact
because they are crumpling
o 90-‐110 is optimal length
Sources of Muscle Energy
o Phosphogen system à ATP + Creatine = ADP + Creatine Phosphate
§ 15 seconds
o Anaerobic glycolosis à muscle glycogen into glucose + 2 ATP = 2 pyruvic acid + 2 Lactic
acid
§ 2 min maximal (slide says 30-‐40sec)
§ Smooth muscle
o Aerobic Respiration à fatty acids, pyruvic from glycolosis, oxygen, amino acids go into
cellular respiration in mitochondria = produces 36 ATP
§ Minutes to hours
§ Cardiac muscle
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Isotonic Contraction: tension remains constant, muscle length changes
o Concentric: muscle shortens à bicep curl
o Eccentric: muscle elongates à squat
Isometric contraction: tension generated is not enough for object to move, muscle doesn’t change
length à plank
Skeletal Muscle Fiber Types
o Slow oxidative (Type I)
§ Small, appear dark red, lots of myoglobin
§ Least powerful type
§ Fatigue resistant
§ Long term aerobic
§ Used for endurance à running marathon
o Fast oxidative glycolytic (Type IIa)
§ Long term anaerobic
§ Intermediate in size, appear red or pink
§ Moderately resistant to fatigue
o Fast glycolytic (Type IIb)
§ Short term anaerobic
§ Large, white, little myoglobin
§ Powerful
§ Intense anaerobic activity of short duration
§ Large motor neuron
§ Low mitochondrial, oxidative capacity
Muscle fatigue: inability of muscle to maintain force of contraction after prolonged activity
o Central fatigue: CNS
o Peripheral fatigue:
§ Inadequate release of calcium ions from SR
§ Depletion of creatine phosphate
§ Insufficient oxygen
§ Depletion of glycogen
§ Buildup of lactic acid and ADP
§ Failure of motor neuron to release enough ACh
Myoglobin – protein that can store oxygen; useful for aerobic respiration and long term energy
supply (type I fibers)
Rigor Mortis – no ATP so muscles cannot relax
Latent period of contraction – brief delay between stimulus and beginning of contraction as AP
moves over the sarcolemma and Ca2+ is released
Curare: plant poison used on arrows and darts
o Blocks ACh receptors inhibiting Na+ ion channels; causes muscle paralysis
Botox
o Blocks release of ACh from synaptic vessels; may be found in improperly canned foods à
respiratory paralysis
Anticholinergenic medication: blocks ACh in CNS and PNS
Myasthenia gravis: immune system disorder where antibodies block ACh receptors (closed eyes is
key)
o Slow enzyme activity of ACh-‐esterase
Chapter 12: Nervous Tissue
o Central Nervous system = brain and spinal cord
o Peripheral Nervous system
o Somatic – special sensory neurons and motor neurons (voluntary)
o Autonomic – sensory: monitor internal environment; motor: involuntary
15
Ariana Dubelko
Sympathetic: fight or flight
• Preganglionic neurons leave from thorocolumbar area of spinal cord
• Preganglionic fibers synapse far from end organ; may synapse with 20 or
more postganglionic neurons
• Postganglionic axons terminate in multiple end organs = widespread effects
• Enzymes that degrade NE are slow so effects last longer
§ Parasympathetic: rest and digest
• Preganglionic neurons leave from craniosacral areas of spinal cord
• Preganglionic neuron usually synapses with 4-‐5 postsynaptic neurons
• Postganglionic neurons supply single visceral effector = specific effects
• Enzyme degrades ACh quickly for short effects
Structural Classification of Neurons
o Multipolar – several dendrites and one axon; most brain and spinal cord neurons
o Bipolar – one main dendrite and one main axon; special sensory receptors found in retina
of eye, inner ear, olfactory area of brain
o Unipolar – dendrites and one axon that are fused together; cell body is to the side; sensory
neurons touch and pain ex
Title: Final study guide for Anatomy I
Description: SMU 2441 - first semester of sequential anatomy classes Chapters include: chemical organization, cellular organization, tissue organization, Integumentary system, Osseous tissue, axial skeleton, appendicular skeleton, joints, skeletal muscle tissue, nervous tissue and the autonomic nervous system
Description: SMU 2441 - first semester of sequential anatomy classes Chapters include: chemical organization, cellular organization, tissue organization, Integumentary system, Osseous tissue, axial skeleton, appendicular skeleton, joints, skeletal muscle tissue, nervous tissue and the autonomic nervous system