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Unit F221: Molecules, Blood and Gas Exchange
Module 1: Molecules and Blood
1
...
1 Biological molecules and cells
Context and exemplification

Proteins, carbohydrates and lipids are three of the key groups of macromolecules essential
for life and health
...
These molecules
are the building blocks of cells, the basic units of all living things
...
This is because
water molecules are polar and possess tiny positive and negative charges over their
surface
...
5°

Chemistry of water molecules

These characteristics make water a good solvent, able to dissolve charged (eg salt
ions) / other polar substances (eg glucose)
...
It is also a metabolite (it is actually needed certain chemical
reactions eg hydrolysis)
...
This means that it needs a lot a energy to heat it
up and takes a long time to cool down
...




It is a good coolant; when water molecules evaporate they take with them a large
amount of energy, (high latent heat of vaporisation)
...

Carbohydrates have the empirical formula (CH2O)n
...




The most common and important
monosaccharide is glucose, which is a
six-carbon or hexose sugar, so has the
formula C6H12O6
...




Carbon has 4 bonds, Oxygen 2 bonds and Hydrogen 1 bond so count them all to make
sure each atom has the correct number of bonds



The carbons of the ring are numbered 1- 6
...
1 being the carbon at the 3 o-clock
position



Describe the formation of a glycosidic bond between 2  glucose molecules to make
maltose (a disaccharide)
...




Condensation reactions release water (H2O)
...


(q) outline the role of glucose as a respiratory substrate;


Monosaccharides have two major functions:
1
...

2
...
g
...
Ribose is used to make RNA and deoxyribose to make DNA
...




 glucose monomers are linked by condensation reactions to form glycogen



Glycogen is a compact storage form of glucose in animals and fungi
...





It is insoluble and therefore doesn‘t affect the water potential / chemistry of cells
...


Glycogen can be mobilised

(broken down to glucose for energy) very quickly
...


(t) describe, with the aid of diagrams, the basic structure of glycerol and fatty acids;
(u) outline the formation of triglycerides by the condensation reactions between glycerol and
fatty acids;

(v) describe the structures of saturated and unsaturated fatty acids and outline their roles
and importance in the human body;

Triglycerides are commonly called fats or oils
...




Glycerol is a small, 3-carbon molecule with three alcohol groups …



Fatty acids are long molecules with a polar, hydrophilic end and a non-polar,
hydrophobic "tail"
...
The
hydrocarbon chain is sometimes called an R group, so the formula of a fatty acid can
-

be written as R-COO
...
e
...
These fatty acids form straight chains, and
have a high melting point
...
e
...
These fatty acids form bent chains, and
have a low melting point
...




One molecule of glycerol joins together with three fatty acid molecules to form a
triglyceride molecule, in another condensation polymerisation reaction:

Lipids (fats)

Animated tutorials macromolecules



Triglycerides are insoluble in water
...
They yield more energy per unit mass than
other compounds so are good for energy storage
...




Lipids can also be used to store fat-soluble vitamins (eg Vit D and A) within cell
globules
...
At room temperature they are solids (fats), e
...

butter, lard
...
At room temperature they are liquids
(oils), e
...
fish oil, vegetable oils
...

High levels of cholesterol have been linked to heart disease
...


(w) describe, with the aid of diagrams, the structure of a phospholipid molecule
...
There may also be other groups attached to the phosphate
...
This mixture of properties is
fundamental to biology, for phospholipids are the main components of cell membranes
...
This is
called a micelle
...
This traps a
compartment of water in the middle
separated from the external water by the
hydrophobic sphere
...


(f) compare the ultrastructure of a leucocyte and a palisade mesophyll cell, as seen with an
electron microscope, to illustrate the differences between animal and plant cells as examples
of eukaryotic cells (to include the cell surface membrane, Golgi apparatus, rough and
smooth endoplasmic reticulum (ER), ribosomes, lysosomes, vesicles, mitochondria,
chloroplasts, cytoskeleton, cell wall, nucleus and nucleolus);
Animated tutorials –
eukaryotic cell tour

Amazing cell video

Interactive cell

Virtual cell tour

ORGANELLE
Cell wall

STRUCTURE and FUNCTION
Cellulose fibrils running through a matrix of complex polysaccharides
...
The fibrils of different layers are orientated
at different angles to form a mesh
...
Gaps between the fibrils
allowing permeability to water and ions
...

Selectively permeable barrier controlling exchange between cell and it‘s
environment
...

Contains DNA (the molecule of inheritance which contains the code for
protein synthesis)
...

Double membrane (envelope), the inner
membrane folded into cristae, stalked
particles on cristae, matrix, 70s ribosomes,
circular DNA
...

Site of aerobic respiration - Kreb's cycle
(in the matrix) & Oxidative phosphorylation
(on the cristae)

Chloroplast

Double membrane (envelope), thylakoids,
grana , stroma, starch grains, 70s
ribosomes, circular DNA, lipid droplets
Site of photosynthesis
...
g
...


Ribosomes

1 Large and 1 small subunit
...

Units responsible for the interpretation of the genetic code ( using
messenger RNA and transfer RNA molecules) and the subsequent
synthesis of proteins from amino acids via the formation of peptide bonds
...
Continuous with
outer membrane of nuclear envelope
...
The proteins may have sequences of amino acids
removed and have short carbohydrate chains added to form glycoproteins
...


Smooth ER

Golgi apparatus

No ribosomes on surface of cisternae – synthesis of steroids and lipids
(triglycerides)
...
At one end
(cis region) these cisternae are constantly being formed from ER
...

Transports and chemically modifies protein material within it and directs
matured proteins to their correct destination (in the cell, on the membrane
or for exocytosis)
...
10
...

Contain hydrolytic enzymes which digest biological material such as old
organelles, material taken in by endocytosis (eg phagocytosis) , secreted
to breakdown external material (eg cartilage) or even destroy the entire
cell itself (autolysis)
...
It is the various sizes and chemistry if
the R groups which greatly influence how the amino acids will affect the structure and
function of the proteins they can build
...
A peptide
bond forms during a condensation reaction (water released) between the carboxylic
group of one amino acid and the amino group of an adjacent one
...
Primary structure – the sequence that particular amino acids are linked together is
called the primary structure of a protein (polypeptide)
...
Altering the amino acid types and/or sequence will
change the shape and nature of the protein that forms
...
Secondary structure – localised folding within a polypeptide chain form recognisable,
organised shapes
...
Globular

To
p
of
the
Do
cu
me
nt

proteins like haemoglobin and enzymes possess a high degree of this type of secondary
structure
...


3
...
It is
stabilised by several types of chemical interaction : hydrogen bonding (C+=O- ---- HN+), ionic bonds (i
...
COO— ---- NH3+), hydrophobic / hydrophilic interactions and

_

disulphide bridges - strong covalent bonds that form between two cysteine amino acids
R groups, (-S-S-)
...
Quaternary structure – more than one polypeptide chain can interact to form a final
protein complex eg haemoglobin
...

o Haemoglobin is a globular protein
...
The hydrophobic R groups are in the middle of the sphere
(away from the water in the cytoplasm) whilst the hydrophilic R groups are on the outside
(in contact with the aqueous cytoplasm)
...

o Each of these chains surrounds a prosthetic group called a haem group
...

o Each haem groups Fe2+ ion can bind to 1 molecule of oxygen (O2)
...


o

Each haemoglobin molecule can bind to 4O2 molecules to form oxyhaemoglobin

(Hb + 4O2  Hb08)
o Know that when every haem group of every haemoglobin molecule in a sample of blood
is bound to an oxygen molecule (O2), the blood is said to be 100% saturated
...

o Gasses diffuse from areas where they are concentrated (high partial pressure)  to
areas of lower concentration (low partial pressure)
...

Partial pressures and gas diffusion

Sickle cell anaemia – people suffering from this genetic disorder have unusual
haemoglobin
...

This is caused by a mutation which results in one of the protein‘s amino acids, glutamic
acid, being substituted for valine
...
This
stiffens the red blood cells which form a ‘sickle’ shape
...
A ‗crisis‘ can occur
...


1
...
2 Blood
Context and exemplification
Blood is a complex transport medium containing blood plasma and specialized cells
...
The electrolytes dissolved in blood plasma affect the water potential
of blood and tissue fluid
...

Assessable learning outcomes
Candidates should be able to:
(a) describe how blood samples are taken and blood smears (films) are made;
(b) describe the procedure for the differential staining of blood smears to show leucocytes;
Making a blood film:
Venipuncture
video

Blood

Blood smear technique

Leishman‘s staining procedure

Venipuncture procedure:
1
...

This prevents viruses being transmitted between the two people
...
The skin is swabbed with alcohol prior to puncture
...
A tourniquet is pulled around the upper arm to make the veins stand out more
...
The needle of a hyperdermic syringe is inserted into a vein some 3-4 inches down from
the tourniquet at an angle of approx 30° and the blood is slowly drawn into the barrel
...
Relax the tourniquet and immediately place a cotton wool swab over the puncture wound
as soon as the needle is removed
...
Cover with a sterile dressing once bleeding has stopped
...
The most widely used type of chamber is called a
haemocytometer, since it was originally designed for performing blood cell counts
...
Each
square has a surface area of one square mm, and the depth of the chamber is 0
...
Thus the entire counting grid lies under a volume of 0
...

Suspensions should be dilute enough so that the cells or other particles do not
overlap each other on the grid, and should be uniformly distributed
...
Now
systematically count the cells in selected squares so that the total count is 100 cells
...
For cells that overlap a
ruling, count a cell as "in" if it overlaps the top or right ruling, and "out" if it overlaps
the bottom or left ruling
...
In that case you will need to multiply your final count by the dilution
factor
...
y
outube
...
Red blood cells
(erythrocytes) have only on the inside
...

This helps maintain the cells distinctive biconcave shape
...
The contents of cells are
essentially solutions of numerous different solutes, and the more concentrated the
solution, the more solute molecules there are in a given volume, so the fewer water
molecules there are
...


Osmosis
:

Facilitated diffusion



Facilitated diffusion is the passive transport of substances across a membrane by a
trans-membrane protein molecule
...
As the name suggests, this is a passive diffusion process, so no energy is
involved and substances can only move down their concentration gradient
...
This allows
charged substances (usually ions) to diffuse across membranes
...

Carrier Proteins - have a binding site for a specific solute and constantly flip between two
states so that the site is alternately open to opposite sides of the membrane
...



Active transport is the pumping of substances across a membrane by a transmembrane protein pump molecule
...
The proteins are highly specific, so there is a different protein pump for each
molecule to be transported
...
Pumping is therefore an active process, and is the only transport mechanism
that can transport substances up their concentration gradient
...
This transport protein is present in the cell membranes of all animal
cells and is the most abundant and important of all membrane pumps
...
This means that,
apart from moving ions around, it also generates a potential difference across the cell
membrane
...
It varies
from 20 to 200 mV, but and is always negative inside the cell
...


Transport across membranes interactive

Membrane quiz

(f) describe the normal composition of blood plasma;


Blood is a specialised tissue containing a number of different living cell types floating in
watery liquid called plasma
...
This pale yellow liquid is
made up of 90% water and 10% dissolved substances
...
It contains dissolved glucose, amino acids, salts
and vitamins; and suspended proteins including hormones (eg insulin, oestrogen),
antibodies, albumin – soluble proteins which help maintain the osmotic balance,
blood clotting factors (eg fibrinogen) and fats
...




Serum - purified blood plasma used in hospitals for blood transfusions
...
It is
essentially blood plasma minus the blood clotting factors, such as fibrinogen
...




Tissue Fluid - the solution surrounding cells
...
It is formed by the filtration of
plasma through capillary endothelial pores (gaps between the cells making up the
walls of the capillary)
...


o

o

This fluid now forms tissue fluid surrounding the cells
...


o

At the venous end of the capillary bed the blood is at low pressure
...
Solutes (such
as carbon dioxide, urea, salts, etc) enter the blood by diffusion, down their
concentration gradients
...


Not all the plasma that left the blood returns to it, so there is excess tissue fluid
...


Lymph - the solution inside lymph vessels
...


(d) describe the structure, as seen with a light microscope, of red blood cells (erythrocytes),
neutrophils, lymphocytes, monocytes and macrophages as specialised cells with particular
functions related to their structures;



Erythrocytes (red blood cells) - make up approximately 45% of blood
...
A pigment called
haemoglobin combines with the oxygen in the lungs to form oxyhaemoglobin
...

The main function of RBC is the transport of
respiratory gasses
...
RBC have
specific features that make it efficient in
absorbing and transporting respiratory gasses
...
This
means that all the haemoglobin molecules are
close to the surface, allowing oxygen to be
picked up and release rapidly
...
It allows the cell to contain a lot of haemoglobin while
still allowing efficient diffusion through the plasma membrane
Organelles – RBC do not contain either nuclei or mitochondria
...



Leucocytes (white blood cells) - are nucleated amoeboid cells, which are much larger
than red blood cells and protect us against disease
...
White blood cells (WBC) are arranged
according to whether they are granular or agranular
...
There are three kinds - neutrophils,
eosinophils and basophils
...
There are two types - lymphocytes and monocytes
...
It has a multi lobed nucleus allowing it to squeeze through the tiny gaps
in capillary walls into surrounding tissues
...


Monocytes (macrophage) – travel in the blood stream and migrate into tissues such as
the lungs and lymphatic system
...


Lymphocytes - B cells produce antibodies which target disease very specifically
...


(k) describe phagocytosis and the processes of endocytosis and exocytosis, with reference
to neutrophils;



Neutrophils (travel in blood stream) and macrophages (present in tissues) are
phagocytes
...
Endocytosis is the localised folding of the cell‘s membrane to form a vacuole
(phagosome) around the object which is drawn into the cell
...
This is then expelled from the cell by
the reverse process of exocytosis
...
Water potential (Greek letter ‗psi‘) is
simply the effective concentration of water
...
Pure water has is given the water potential
value O kPa
...




Cells and Osmosis - the concentration of the solution that surrounds a cell will affect the
state of the cell, due to osmosis
...
)
Hypotonic solution

- a solution of higher water potential than a cell (low solute conc
...
If the body dehydrates the water
potential of the blood plasma, tissue fluid and cytoplasm of cells lowers and the solutes
(eg plasma proteins, electrolytes, glucose) become more concentrated
...

(h) explain the importance of electrolytes in body fluids and outline how they are
measured in plasma and urine;

How ionic substances
(electrolytes) dissolve



Glucose and other solutes dissolved in blood plasma lower the water potential but
electrolytes (charged ions – eg potassium, sodium, chloride and bicarbonate ions) are
mainly responsible for maintaining the osmotic balance
...
Monitoring the levels of electrolytes in blood plasma and urine is
important in the diagnosis and management of diseases such as diabetes and kidney
disease
...




Strenuous exercise can dehydrate the body due to sweating
...
) These salts are called electrolytes
...

Isotonic drinks not only replace water but also the inorganic salts lost during prolonged
sweating
...

Glucose may also be present in ―sport drinks‖ as this is the body‘s main respiratory
fuel
...
This
disease results from a failure to produce enough insulin, the hormone responsible for
removing glucose from the blood stream after a carbohydrate meal and lowering its
plasma concentration to a safe level
...
A test strip impregnated with the enzyme glucose
dehydrogenase is inserted into the sensor after a drop of blood has been placed in
contact with the strip
...
The reaction produces a small electric current which is converted into
a measurement for blood glucose concentration after 30 seconds (mmol dm-3)
...
1
...
Enzymes
play a key role in the prevention of blood loss, through their involvement in blood clotting
...




Enzymes possess a region called the active site, to which molecules, complementary to the
active site can bind
...




Enzyme catalysed reactions form an enzyme-substrate complex
...
This forms an enzyme-substrate complex, which reduces the
activation energy required for a reaction to proceed
...




Understand the ‗Lock and Key‘ hypothesis – one enzyme will only act on one substrate
...
The
enzyme is said to be specific for its substrate
...




Know that as a reaction proceeds, the concentration of the substrate decreases (because it
is used up), and the concentration of the product increases (because it is being made)
...


Rate of
reaction

Rate of Reaction – decreases with time:
substrate molecules used up – less chance
of substrate colliding with enzyme
...

This is when you should measure the rate of reaction
...




Understand that denaturation of enzymes is an alteration in their tertiary (and secondary)
structure, so that the shape of the active site is no longer complimentary to the substrate
...




Changes in the following factors affect the rate of reaction of enzyme catalysed reactions:
Temperature - increasing temperature up to the optimum temperature increases the rate
of reaction as more collisions between substrate and active sites occur
...


For mammalian enzymes the optimum working
temperature is about 40°C, but there are enzymes that
work best at very different temperatures, e
...
enzymes
from the arctic snow flea work at -10°C, and enzymes
from thermophilic bacteria work at 90°C
...
For most enzymes this is
about pH 7-8 (physiological pH of most cells), but a few enzymes can work at extreme pH,
such as protease enzymes in animal stomachs, which have an optimum of pH 1
...
The enzyme is said to be denatured
...


Enzyme concentration - the rate of reaction is directly proportional to enzyme
concentration
...

As the enzyme concentration increases the rate of the
reaction increases linearly, because there are more
enzyme molecules available to catalyse the reaction
...
Normally enzymes are present in
cells in rather low concentrations
...
Increasing the concentration
of substrate molecules  increases the chance of an enzyme-substrate complex forming
 increases the rate of reaction
...


Competitive and non-competitive inhibition Competitive inhibitors have a similar shape to the substrate molecules can fit into the
active site of the enzyme, as they are complementary in shape to the active site
...
When the inhibitor is occupies the active
site the substrate cannot bind so the overall rate of reaction decreases
...
whfreeman
...
asp

Inhibitors can be reversible (temporary binding) or irreversible (permanent binding)
...


Non-competitive inhibitors have a different shape to the substrate
...
This
binding site is called an allosteric site
...
This is an example of competitive inhibition, and is a way
of regulating the rate of production of the product
...


(a) describe the first-aid procedure to prevent excessive blood loss;

St John Ambulance service – advice on
stopping bleeding


First aid video – how to stop bleeding

Severe bleeding poses a very real risk of death to the casualty if not treated quickly
...
Most protocols advise the use of direct pressure, rest and
elevation of the wound above the heart to control bleeding
...

Tourniquets should rarely be used as it is usually possible to stop bleeding by the
application of manual pressure
...
When we bleed, platelets, chemicals and substances called clotting
proteins (prothrombin) help to form an insoluble 'plug' to seal off the bleeding point
...
1
...

Assessable learning outcomes
Candidates should be able to:
(a) describe the conditions in which blood for transfusion is stored;
Blood transfusion website
(b) describe and explain the effects of changing pH and changing temperature on enzyme
activity, with reference to the storage of blood for transfusion;

pH - pH is a measure of how acidic or alkaline a solution is
...
As altering
the pH affects the tertiary bonding within an enzyme causing denaturation
...
A phosphate buffer is
added to blood for storage
...

pH explanation
Temperature - Whole blood is stored at 4 C
...
Particularly high temperature above
40 C would result in the denaturation of proteins such as haemoglobin
...
These would damage cell membranes and destroy
the blood cells on thawing
...
They are present in the
blood plasma and also released by platelets during the clotting process
...
This is done by adding
anti-coagulants such sodium citrate
...


Blood naturally

contains an enzyme called antithrombin, a reversible enzyme inhibitor, which binds with
thrombin, partially masking its active site
...


Heparin binds to antithrombin altering its tertiary structure and causing thrombin to bind
more strongly to thrombin thereby reducing the tendency for blood to clot
...

Generally only used when a patient is losing a lot of blood, such as during a major
operation
...
It can be diluted with a saline (salt) solution and used in blood
transfusions
...
Used to treat severely anaemic patients or to replace red blood cells after
childbirth
...
It can be stored frozen
...
These can be used to treat patients who have factors missing
eg haemophiliacs
...

Leuco-depleted blood - involves the use of filters to remove the majority of leucocytes
(WBC) from donated blood prior to storage
...
There will also be fewer allogenic
leucocytes
...


(f) outline how blood products are screened and treated to prevent the transmission of HIV
and hepatitis C
...
On acceptance, a blood sample is taken analysed
...
Carriers of these diseases will have antibodies in their blood
...


Module 2: Circulatory and Gas Exchange Systems
1
...
3 The Lungs and Investigating Lung Function
Context and exemplification





The way in which cells grow and become specialised to form tissues and organs is
fundamental to our understanding of the way in which the body works
...

Measurements of lung function are also carried out on athletes during training
...


Assessable learning outcomes

Candidates should be able to:

(e) relate cell size to cell surface area to volume ratio, in relation to the exchange of
materials with the environment;


All organisms need to exchange materials between themselves and their
environment
...




Diffusion is quick enough to supply the required materials to all parts of a small
organism, due to the fact that small organisms have a large surface to volume ratio
(SA:V), therefore a short diffusion pathway
...




Large organisms therefore need a specialised transport system to decrease
diffusion pathways to allow all cells to exchange materials by diffusion in a quick
manner



Other factors to consider
o

The activity level of an organism – if the organism is highly active, they will
need to rely on a transport system to get O2 to all respiring cells quickly
...


(a) explain the meaning of the terms tissue and organ;
(b) explain the relationships between cells, tissues and organs, with reference to squamous
epithelial cells in the alveoli of the lung;


Understand that cells can be organised into tissues
...
The cells are specialised for
a particular function
...
g
...




Epithelial tissue is arranged in single or multilayered sheets and covers the internal
and external surfaces of the body
...




Epithelium rests on a basement membrane which is a connective tissue matrix
containing collagen fibrils
...




Different tissues can be organised into larger structures called organs
...

o

In animals an example would be the stomach which contains muscular tissue to
mix the food, secretory tissue to produce enzymes, acid and mucus and nervous
and hormonal tissue to control the churning & secretions
...


(c) describe, with the aid of diagrams and photographs, the structure of ciliated epithelium,
goblet cells and squamous epithelial cells and relate their structures to their functions;
(d) describe and interpret photomicrographs of lung tissue;

“C” shaped cartilage rings

Elastic fibres

Blood vessels
Smooth muscle
Epithelium consisting of goblet cells
and ciliated cells (see next diagram)

Mucus produced by goblet
cell with trapped dust and
micro organisms

Ciliated cell with protruding
cilia to move mucus

Goblet cell producing
vesicles containing mucus
which line the trachea



Squamous epithelium is a single sheet & contains cells which are:
o

Thin & flattened - to provide a short distance for diffusion of gases (e
...
in
the alveoli of the lungs) and materials (any capillary) across them
...


o

Smooth - to provide a smooth surface and so reduce friction to fluids (e
...

lining of blood vessels - endothelium)
...
The cells are columnar
...
The cells are always associated with goblet cells which
secrete mucus
...
The current of mucus (snot)
carries anything within in it in the direction of the flow (e
...
dust and bacteria in the
trachea, bronchi & bronchioles up to the throat for swallowing)
...


http://www
...
com/watch?v=miEEluVlemQ
clip outlining goblet and ciliated cell functions

(f) outline the main features of the gaseous exchange surface of the lungs (only details
relating to the cells in contact with blood capillaries, elastic fibres and the role of surfactant
are required);


Know that the alveolar capillary membrane is the gaseous exchange surface of the
mammal
...




Know that the alveolar walls contain elastic fibres which stretch during breathing
and recoil during expiration to help force air out
...
When fully
expanded during exercise, the surface area available for diffusion increases, and the air is
expelled efficiently when the elastic fibres recoil
...




Know that the uptake of oxygen is increased because the red blood cells are forced
to squeeze slowly through the alveolar capillaries & therefore expose a greater
surface area over a longer period of time for gaseous exchange to take place
...
0001mm thick) there is rapid
diffusion of gases in & out of the lungs
...




Know that the surfactant stops the alveoli collapsing when the pressures in the lung
change during ventilation
...
The smooth
muscle may constrict decreasing the size of the lumen (diameter of opening)
restricting air flow to the alveoli

o

Finally air passes into the alveoli, it does not have any cartilage or smooth
muscle, but does have elastic fibres that help it recoil and force air out of the
alveoli when exhaling
...
The alveoli is
the site of gas exchange

Short diffusion pathway

Alveoli walls are one cell thick
Capillary wall one cell thick
Both walls are composed of very thin
squamous cells

Maintain concentration gradient of O2

Alveoli – the air in the alveoli is

and CO2

constantly being replaced, CO2 moves
out and O2 when you exhale and inhale
Capillary – the blood is constantly bring
blood high in CO2 to the exchange
surface and taking away oxygenated
blood

http://www
...
com/watch?v=q-hQ3PabJ20&feature=related
http://health
...
com/adam-200022
...

The tidal volume at rest is about 0
...




vital capacity is the maximum volume of air that can be breathed in and then out of
the lungs by the movement of the diaphragm and ribs
...
6dm3
...

When a person breathes in via a mouth piece the chamber moves up, when they
breath out the chamber moves down



movements of the spirometer produce a trace

Example of a trace from a spirometer



note that the trace moves down to the right, this is because the oxygen in the
chamber of the spirometer is being used by the person breathing (red arrow)



this person took a deep breath just after a minute on the spirometer

Using the trace above
a
...
Next count
from trough to trough as equal to one breath, therefore = 9 breathes min-1

One
breath

60 s

40 s

b
...
6dm3

Vital capacity =
4
...
calculate the volume of oxygen absorbed by this person in the first minute
Answer: As mentioned earlier the trace moves down to the right due to oxygen being
absorbed by the body, therefore

Amount of oxygen
absorbed in the first
minute = 1
...




Peak expiratory flow rate (PEFR) is measured using a peak flow meter
...
Repeat 3 times and take the
highest reading
...


(j) describe the possible causes of respiratory arrest;

Respiratory arrest can be caused by:


Airway obstruction can be a blockage in the upper or lower airway, key thing to
note is that infants often breathe through the nose so this could be where their
blockage is
...
g
...




drug overdose of respiratory depressant drugs eg morphine, barbiturates

(k) explain how expired air resuscitation should be carried out on adults, children and babies
in order to maintain blood oxygen concentration
...


o
o

Give two breaths and then check for a pulse

o


You should make sure the airway is open and there are no obstructions

You should maintain one breath every 5 seconds

If the pulse stops you should perform CPR (cardiopulmonary resuscitation)

Children and infant rescue breathing



Use the same guidelines as above however you do not need to pinch their nose you
need to cover their mouth and nose with your mouth
...


1
...
2 The Circulatory System
Context and exemplification


It is important for health professionals and individuals to monitor blood pressure in
order to prevent or diagnose problems relating to the circulatory system
...
travellersthrombosis
...
uk/soleuspump
...




There are gaps (endothelial pores) between
them which allows plasma (minus the large
plasma proteins) to leak through & form tissue
fluid
...
Then as it travels further away from the heart it loses pressure due to
resistance/friction on the vessel walls
...




Velocity falls in line with blood pressure
...
The velocity increases again in veins when the
capillaries rejoin larger vessels (venules and veins)
...


You should able to identify diagrams of the blood vessels as seen through a light microscope
Red blood cells
(in lumen of
artery)
Vein
(Thin walls, large

Artery
(Thick walls,

lumen)

small lumen)

(e) explain the importance of the closed double circulatory system in maintaining differences
in blood pressure in different parts of the circulatory system;


an effective transport system will have the following
o

a pump to create pressure to push nutrients around the body(heart)

o

a medium to contain the nutrients (blood)
o


tubes or vessels to carry the blood

There are two main types of closed* circulatory systems, the

single circulatory system and the double circulatory system


The double circulatory system
o

Consists of two circuits

o

The pulmonary circuit – moves deoxygenated

blood from heart to the lungs and oxygenated blood back to the
heart
o

The systemic circuit – moves oxygenated blood

from the heart to the rest of the body and returns deoxygenated
blood to the heart
o

Blood therefore moves through the heart twice in one

complete loop
o

The heart therefore consists of four chambers, two

collecting chambers and two pumping chambers
o

Oxygenated and deoxygenated keep separated in

heart
o

Blood can be pressurised twice in one complete loop which helps maintain
flow around the whole body
...
3kPa) due to this end
of the capillary being closest to the heart, this is also known as hydrostatic
pressure



In the blood there are large plasma proteins that can not pass through the small
gaps between the cells lining the capillaries, these act as a solute and therefore
exert a solute pressure potential (Ψs) of -3
...
0kPa
( 4
...
3) = 1
...
1kPa) and the tissue fluid not containing as many solutes, having a low Ψs (1
...
1 kPa



Due to the pressure differences between the blood in the capillary and tissue fluid,
plasma is force through the capillary pore (but not the large plasma proteins or red
blood cells) down the pressure gradient to bath the cells in tissue fluid



Tissue fluid re-enters the venous end of the capillary due to the hydrostatic pressure
being low at this point (1
...
3 kPa, resulting in an over
effective blood pressure of -1
...
3 kPa blood pressure

Plasma

Venous end
Of capillary

Red
blood cell

-3
...
6 kPa blood pressure
-3
...
0 kPa

-1
...
1 kPa tissue fluid pressure

Tissue fluid

-1
...
1 kPa

cell

cell

cell

1
...
1 The Heart and Monitoring Heart Function
Context and exemplification



It is important for health professionals to be able to monitor the action of the heart,
either by measuring the electrical changes that take place, or through effects on the
circulatory system
...


Assessable learning outcomes
Candidates should be able to:

(a) describe, with the aid of diagrams and photographs, the internal and external structure of
the human heart;


You should be able to draw & label the mammalian heart (i
...
right & left atria, right &
left ventricles, tricuspid (right) & bicuspid (left) valves (atrioventricular valves),
interventricular septum, papillary muscles, tendinous cords, inferior & superior vena
cava, pulmonary artery, pulmonary vein, aorta, semilunar valves, carotid artery,

http://www
...
com/watch?v=rI23fdFVRvY
Informative movie of a heart dissection showing the path of blood through the heart

Diagram of Internal Structure of a Mammalian Heart

(Tricuspid)

Tendinous
cords

(Bicuspid)

papillary muscles

External View of the Heart Showing the Coronary Arteries

http://www
...
com/watch?v=WXwYYsi6z7Q
Movie of valves of the heart, please note the pulmonary and aortic valves can be called semi lunar valves due to
their shape, and the mitral valve is also known as the bicuspid valve

(b) describe the cardiac cycle, the role of the valves and the pressure and volume changes
occurring in the heart;


When the atria contract (atrial systole) the pressure in the atria is greater than the
pressure in the ventricles, forcing blood through the atrioventricular valves and into
the ventricles
...




The pressure is so great in the ventricles that the valves would be forced open in the
opposite direction (i
...
allow blood to move from the ventricles  atria), this process
is prevented by the papillary muscles contracting at the same time as the ventricles
...




The blood can then only flow in one direction from the ventricles  the arteries
leaving the heart (via the pulmonary artery & aorta) where the pressure is lower
...

Because the arteries are elastic, they recoil back to their original shape
...
e
...
This is prevented because as the blood moves towards the
ventricles, it hits the semilunar valves in the arteries and forces them shut (2nd heart
sound ―dub‖)
...
REMEMBER: blood only moves from HIGH  low
pressure
...
med
...
edu/kw/pharm/hyper_heart1
...
To calculate how long a
single heartbeat lasts:
0
...
1 secs = 0
...




Electrical waves cause the heart muscle to pump
...
Electrodes on different
sides of the heart measure the activity of different parts of the heart muscle
...


Initiation of the heart


Know that the sino-atrial node (SA node) is made of specialised cardiac muscle
tissue (NOT NERVOUS TISSUE) located in the wall of the right atrium
...




Know that this impulse spreads across both atria very quickly and as it does so,
causes the muscles of the atria to contract simultaneously (atrial systole)
...




The only way that the impulse can spread to the ventricles is through a structure
called the atrioventricular node (AV node)
...




From the AV node, the impulse travels down specialised cardiac muscle fibres (in the
interventricular septum) called the Bundle of His
...




The electrical impulse is 1st conducted to the tip (apex) of the heart so this bit
contracts first
...


Electrical system of the heart

http://www
...
com/templatedata/imports/HTML/CRM/heart/interact_8
...

Cardiac output (CO) = heart rate (HR) X stroke volume (SV)



Cardiac output (CO) is the volume of blood which is pumped from the heart
(specifically the left ventricle) in one minute (approx
...




Stroke volume (SV) is the volume of blood being pumped out in a single contraction
of the heart (approx
...




Heart rate (HR) is the number of beats per minute (approx
...




Cardiac output needs to be maintained however a fitter person may have a lower
heart rate because they have a greater stroke volume
...

Normal person

Fit person

Stroke volume

70cm3

90cm3

Resting heart rate

72/min

55/min

5000cm3/min

5000cm3/min

Cardiac output

(f) describe how the ‗pulse‘ rate can be measured and interpreted
...
This wave of distension travels along all the arteries
...




Each pulse is equivalent to one heartbeat (one cardiac cycle)
...




You should use your second and third finger as you can feel a pulse in your own
thumb and first finger
...


(g) describe how a sphygmomanometer is used to measure systolic and diastolic blood
pressure;
(h) describe how the systolic and diastolic blood pressure measurements are interpreted
...




Know that systolic blood pressure is a measure of the pressure (or force) of blood
leaving the heart, on the blood vessels, when the heart contracts (ventricular
systole)
...
It is an indicator of the resistance of
the small arteries and capillaries to blood flow
...
youtube
...
These are often written as 120/80
...




Causes of hypertension include; high alcohol intake, smoking, obesity, high dietary
salt intake and genetic factors
...




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