topic five - transport in animals - miss whitehouse

Question 1

why are transport systems needed

in multicellular organisms?

Answer 1

size of organism – oxygen used up by outer
layers of cells

low SA:volume ratio – surface area is not large
enough to supply all oxygen and nutrients needed
by internal cells through simple diffusion

level of activity – more active organisms need
more oxygen for the release of energy through
respiration (higher metabolic rate), carbon
dioxide also needs to be removed at a faster
rate

Question 2

name five features of a good a transport system?

Answer 2

a circulating fluid to carry materials around the body – blood (plasma and cells)

a muscular pump to create pressure that will push the fluid around the body – the heart – composed of cardiac muscle

vessels to convey the fluid from one region to another – arteries, capillaries, and veins

exchange surfaces – enable useful materials to enter the blood and to leave it again where they are needed

two circuits (double circulation) – one to pick up oxygen and another to deliver oxygen to the tissues

Question 3

in mammals the double circulatory system has two circuits what are these called?

Answer 3

Pulmonary circulation:
• Blood to lungs
• Low pressure prevents 
damage to capillaries in 
the lungs

Systemic circulation:
• Blood to body organs
• High pressure – blood 
needs to travel a great 
distance

Question 4

single circulatory system features?

Answer 4

Fish

Blood passes through the heart once per complete
circuit of the body

Blood pressure is reduced as blood passes through
capillaries in gills

Blood flow is slow to rest of body

Rate of oxygen delivery limited

Question 5

double circulatory system features?

Answer 5

Mammals

Blood passes through the heart twice per complete
circuit of the body

Heart increases blood pressure after blood has
passed through lungs

Blood flow is fast to rest of body

Rate of oxygen delivery faster

Question 6

what happens in an organisation with an open circulation?

Answer 6

in an organism with an open circulation, blood is not enclosed in vessels but flows freely through the
body cavity

E.g. insects and some other invertebrates

Question 7

what happens in an organisation with an open circulation?

Answer 7

in an organism with a closed circulatory system, blood is
contained in vessels -arteries, veins and
capillaries

E.g. all vertebrates

Question 8

open circulation features?

Answer 8

chambers pump blood forwards by peristalsis

blood re-enters heart through series of valves called ostia

larger insects have some open-ended tubes attached to direct blood flow to active parts

efficient enough for insects as they have the tracheal system to deliver oxygen to cells and to remove carbon dioxide

Question 9

name the types of blood vessels and what they do?

Answer 9

arteries: carry blood (usually oxygenated) away from the heart. arteries have thick walls and a relatively narrow lumen
arterioles: smaller vessels which carry blood between an artery and capillaries
capillaries: the smallest type of blood vessel, with walls only a single cell thick
venules: a small vessel which carries blood between a larger vein and capillaries

veins: carry blood (usually deoxygenated) back towards the heart. Veins have thin walls and a relatively large lumen and
may contain valves

Question 10

name the three types of tissues in vessels?

Answer 10

tunica interna/intima: an 
endothelium lining the 
inside of the vessels. This 
is a layer of squamous 
epithelium that is only one 
cell thick

tunica media: middle band of tissue that contains smooth muscle, collagen and elastic fibres

tunica externa: outer
layer containing collagen
and elastic fibres

Question 11

what do veins contains and what do these do?

Answer 11

veins contain semi-lunar valves formed from their

endothelium which keep blood flowing towards the heart

Question 12

what do valves help?

Answer 12

valves help to overcome the problem of moving blood against the force of
gravity under fairly
low pressure

Question 13

how have arteries adapted to there functions?

Answer 13

very thick walls with smooth muscle to constrict the lumen

lots of elastic fibres in tunica media allow artery walls to
stretch as blood surges through under high pressure, then recoil

relatively narrow
lumen to maintain high pressure

collagen in walls
provides strength
to withstand high
pressure

Question 14

how have veins adapted to there functions?

Answer 14

thin walls as high pressure is not needed

wide lumen

much thinner tunica media than the arteries, with
fewer elastic fibres and less collagen

semi-lunar valves
to prevent backflow

Question 15

how have capiliaries adapted to there functions?

Answer 15

small diameter of 7-8μm ensures that RBC pass through in single file – better for diffusion

walls made of squamous epithelium are only one cell thick – short diffusion pathway

Question 16

examples of blood compostion?

Answer 16

red blood cells (erythrocytes)

white blood cells (leucocytes)

platelets

plasma

dissolved carbon dioxide

dissolved oxygen

glucose

amino acids

fatty acids

mineral ions

plasma proteins

hormones

antibodies

(Heat)

Question 17

what do fenestrations do?

Answer 17

these are tiny pores that exchange of

molecules between the blood plasma and body tissues

Question 18

what’s a capillary bed?

Answer 18

a network of capillaries within a tissue

Question 19

how is tissue fluid formed?

Answer 19

as blood flows through the capillaries in a capillary bed some
of the molecules are forced out of the capillary

Question 20

what do tissue fluid contain?

Answer 20

Water

dissolved oxygen

dissolved solutes e.g.
glucose, amino acids, ions

some hormones and
proteins

very few white blood cells (some phagocytes)

no plasma proteins

Question 21

what does lymph fluid contain?

Answer 21

less oxygen and nutrients than
tissue fluid due to use by cells

more carbon dioxide than tissue
fluid due to cell waste

more fatty material from absorption in intestines

lymphocytes produced in lymph
nodes (a type of WBC)

Question 22

what does systole mean?

Answer 22

means contraction

Question 23

what does diastole mean?

Answer 23

means relaxation

Question 24

what is a atrial systole?

Answer 24

both atria contract

blood flows into the ventricles

valves in the veins close to prevent the backflow of blood

high pressure in the atria forces the atrioventricular valves to open

Question 25

what is a ventricular systole?

Answer 25

both ventricles contract atrioventricular valves pushed shut semilunar valves are pushed open blood flows into the arteries

Question 26

what is a ventricular diastole?

Answer 26

atria and ventricles relax semilunar valves are pushed shut blood flows into the atria through the veins, then through the open AV valves into the ventricles

Question 27

what is a AV valves?

Answer 27

after contraction, the ventricles relax and recoil to their original shape this decreases pressure in the ventricles below the pressure in the atria the AV valves open and blood flows into the ventricles during contraction of the ventricles, pressure increases above the pressure in the atria AV valves snap closed to prevent backflow

Question 28

what happens to the semi-lunar valves during ventricle contraction?

Answer 28

they open as the pressure in the ventricles becomes greater than the pressure in the arteries when the ventricles relax and recoil, the pressure inside the ventricles falls to below the arterial pressure this pushes the SL valves closed, as blood starting to push backwards collects in the “pockets” of the valves

Question 29

what happens in the cardiac cycle?

Answer 29

cardiac cycle repeats itself about 70 times each minute when the heart is at rest when the atria contract during the phase called atrial systole, the remaining blood in them is pushed past the atrioventricular valves into the chambers called ventricles contraction of these chambers forces open the semi lunar valves and pushes blood into the pulmonary artery then goes to the lungs, and the aorta, which supplies blood to the rest of the body

Question 30

what's lub in reference to sound of the heart?

Answer 30

louder | AV valves snap shut

Question 31

what's dub in reference to sound of the heart?

Answer 31

quieter SL valves close pockets fill up slowly

Question 32

what does myogenic mean?

Answer 32

means it can initiate its own contraction - it does not require stimulation from the nervous system like most muscles do

Question 33

what are ECGs?

Answer 33

an ECG detects the electrical activity of the heart using sensors attached to the skin they can be used to diagnose heart conditions

Question 34

what are the different parts of the trace?

Answer 34

P – excitation of the atria leading to atrial systole QRS – excitation of the ventricles leading to ventricular systole T – the start of diastole

Question 35

name some conditions that are shown on an ECG trace?

Answer 35

Myocardial infarction – heart attack Atrial fibrillation – atria contract more frequently than the ventricles Arrhythmia – irregular heartbeat with lack of coordination Enlarged heart

Question 36

what is a bradycardia mean?

Answer 36

heartback is too slow

Question 37

what is a tachycardia mean?

Answer 37

heartback is too fast

Question 38

what is a ectopic heartbeat?

Answer 38

heartbeats that are earlier than expected

Question 39

how is oxygen carried and what does this form?

Answer 39

oxygen is carried in erythrocytes (RBC) by the globular protein haemoglobin this forms oxyhaemoglobin in a reversible reaction

Question 40

each subunit is associated with a prosthetic haem group, what does this contain?

Answer 40

containing an Fe2+ ion that has an affinity (attraction) for oxygen

Question 41

how many oxygen molecules can haemoglobin carry?

Answer 41

four oxygen molecules

Question 42

what is dissociation of oxyhaemoglobin?

Answer 42

happens in respiring | tissues and involves the release of oxygen from haemoglobin

Question 43

what two properties to be effective, what are these?

Answer 43

readily associate with oxygen at a gas exchange surface readily dissociate from oxygen at respiring tissues

Question 44

what does a dissociation curve show?

Answer 44

shows the proportion of haemoglobin that is saturated with oxygen at different oxygen concentrations

Question 45

what happens at a low oxygen tension?

Answer 45

haemoglobin doesn't readily take up oxygen molecules ``` this is because the haem groups are in the centre of the haemoglobin molecule and the four subunits are closely united, making it difficult for the first oxygen molecule to reach the haem group and bind ```

Question 46

what happens at an increased oxygen tension?

Answer 46

diffusion gradient becomes steeper haemoglobin undergoes a conformational change – the molecule changes shape slightly, allowing oxygen molecules to associate with the remaining three haem groups more easily

Question 47

what happens at a very high oxygen tension?

Answer 47

the slope of the line levels off this is because once three oxygen molecules have become associated with haem groups, it is difficult for the fourth molecule to diffuse in and bind

Question 48

what must a foetus be able to do?

Answer 48

must be able to load oxygen from its mother's | blood

Question 49

how does respiration do to the foetus?

Answer 49

due to the respiration occurring in the foetus' cells, the partial pressure (concentration) of oxygen is lower in the foetus’ blood than in the mother's blood

Question 50

why does not much oxygen diffuse across the foetus?

Answer 50

because of the relatively small concentration difference

Question 51

what happens in order to maximise the amount of oxygen a foetus receives?

Answer 51

it has a different respiratory pigment - foetal haemoglobin. this has a higher affinity for oxygen than adult haemoglobin at any partial pressure of oxygen, so the foetus can always obtain oxygen from the mother’s haemoglobin

Question 52

what is myoglobin?

Answer 52

Myoglobin is a respiratory pigment found in muscles. It is used to store oxygen (rather to transport it)

Question 53

what does myoglobin provide?

Answer 53

it provides a back-up supply of oxygen for times where muscles are using oxygen for respiration at a faster rate than it can be supplied by the blood

Question 54

what are the effects of carbon monoxide ?

Answer 54

If carbon monoxide is breathed in it binds irreversibly with haemoglobin to form carboxyhaemoglobin. This means that the haemoglobin cannot load and carry oxygen

Question 55

what are three forms that carbon dioxide is carried in?

Answer 55

5% is dissolved directly in plasma 10% is combined with amino groups in polypeptides of haemoglobin molecule to form carbaminohaemoglobin 85% is carried as hydrogen carbonate ions (HCO3-) which move from erythrocytes into the plasma

Question 56

formation of hydrogen carbonate ions?

Answer 56

CO2 diffuses into RBCs and reacts with water (catalysed by carbonic anhydrase). This forms carbonic acid (H2CO3) 2. Carbonic acid dissociates to form H+ ions and hydrogen carbonate ions (HCO3-) 3. H+ ions bind to haemoglobin (haemoglobinic acid). This means oxygen has to dissociate. It is “pushed out” due to distortion of the molecule, which decreases affinity. This is known as the Bohr effect. Haemoglobin is acting as a buffer to maintain a constant blood pH 4. HCO3 - ions diffuse out of RBCs, making them less negative. They are carried in the plasma 5. Chloride shift: Chloride ions then diffuse into RBCs from plasma to replace lost HCO3 - ions and maintain the charge

Question 57

label a heart?

Answer 57

OLC

Question 58

where does an aorta come from and what does it supply?

Answer 58

the aorta comes up out of the heart and arches round - the main (widest) branch runs straight down the centre of the body parallel to the spine, and branches off in the abdomen to supply the digestive organs, kidneys, reproductive organs and legs

Question 59

where do your carotid arteries run from?

Answer 59

your carotid arteries run up | the neck to the brain

Question 60

where does a subclavian artery supply blood to?

Answer 60

the subclavian arteries supply blood to the head, neck, shoulders and arms

Question 61

where does a coronary artery supply blood to?

Answer 61

the coronary arteries supply blood to the heart muscle

Question 62

function of pulmonary vein?

Answer 62

the pulmonary vein brings blood in from the lungs to the left side of the heart

Question 63

function of aorta?

Answer 63

the aorta takes blood away from the left side of the heart to the body organs

Question 64

function of vena cava?

Answer 64

the vena cava brings blood in from the body organs to the right side of the heart

Question 65

function of pulmonary artery?

Answer 65

the pulmonary artery takes blood away from the right side of the heart to the lungs

Question 66

what happens after contraction to the atrioventricular valves?

Answer 66

the ventricles relax and recoil to their original shape this decreases pressure in the ventricles below the pressure in the atria the AV valves open and blood flows into the ventricles during contraction of the ventricles, pressure increases above the pressure in the atria AV valves snap closed to prevent backflow into the atria

Question 67

what happens if there is a blockage of coronary arteries?

Answer 67

a blockage of these arteries leads to myocardial infarction (heart attack) because the heart muscle is deprived of oxygen and so dies