3.1.2 transport in animals

Question 1

what is a closed system

Answer 1

blood is enclosed in blood vessels

Question 2

what is a single closed system and what animals are they found in

Answer 2

one circuit around the body straight to and from the heart
fish and worms

Question 3

what is a double closed system

Answer 3

two circuits going from heart to lungs to heart to body
mammals and birds

Question 4

what is an open system

Answer 4

blood flows from heart to haemocoel (few vessels contain transport medium)

Question 5

what are the blood vessels attached to the heart

Answer 5

vena cava
aorta
pulmonary artery
pulmonary vein

Question 6

what are the valves in the heart

Answer 6

atrioventricular (tricuspid and bicuspid)
semi-lunar valves (pulmonary and aortic)

Question 7

summarise blood flow through the right side of the heart

Answer 7

blood into vena cava
enters right atrium
goes through tricuspid valves
into right ventricle
goes through pulmonary valves
into pulmonary artery
into lungs

Question 8

summarise blood flow through the left side of the heart

Answer 8

blood into pulmonary vein from lungs
enters left atrium
goes through bicuspid valves
into left ventricle
goes through aortic valves into aorta
into body

Question 9

what is the word for the heart being able to stimulate it’s own contraction

Answer 9

myogenic

Question 10

explain how the heart’s basic rhythm is stimulated

Answer 10

SAN causes atria to contract
AVN delays slightly then stimulates bundle of His
conducts excitational wave through to apex
purkinje fibres spread it to ventricle walls
ventricles contract

Question 11

what is a healthy electrocardiogram trace

Answer 11

typical PQRST trace

Question 12

when does systole occur on the ECG

Answer 12

QRS

Question 13

when does diastole begin on the ECG

Answer 13

T

Question 14

what is bradycardia

Answer 14

increased stroke volume of the heart that decreases beats per min
athletes or disease

Question 15

what is tachycardia

Answer 15

ver fast heart rate greater than 100bpm
fear, panic, excersise or SAN issues

Question 16

what is an ectopic heartbeat

Answer 16

extra beat as heart contracts before the first contraction finishes then there’s a short pause
very common

Question 17

what is atrial fibrillation

Answer 17

irregular waves of electrical impulses in atria that causes rapid contraction (arrythmia)

Question 18

what does the cardiac cycle consist of

Answer 18

passive filling, systole and diastole

Question 19

explain the process of systole in the cardiac cycle

Answer 19

atria contract so pressure in atria increases - atrioventricular valves OPEN
blood goes down pressure gradient into ventricles
atria relax
ventricles contract
pressure in ventricles increases above pressure in atria
atrioventricular valves CLOSE
pressure in ventricles gets higher than in arteries - semi-lunar valves OPEN
blood forced into arteries

Question 20

explain the process of diastole in the cardiac cycle

Answer 20

ventricles relax
when pressure in ventricles drops below arteries semi-lunar valves CLOSE
when pressure in ventricles drops below atria atrioventricular valves OPEN again to allow for passive filling

Question 21

what do arteries transport

Answer 21

oxygenated blood away from heart

Question 22

what do veins transport

Answer 22

deoxygenated blood to heart

Question 23

what do capillaries do

Answer 23

exchange oxygen, nutrients and waste between blood and cells

Question 24

describe an artery

Answer 24

small lumen maintains high pressure
thick, smooth muscular wall provides strength and can contract/relax to cope with changing pressure
collagen elastic fibres to recoil and provide strength
folded endothelium lining

Question 25

describe a vein

Answer 25

large lumen to allow a greater volume of blood through at low pressure
thin wall as less support is needed
valves to prevent backflow of blood

Question 26

describe a capillary

Answer 26

squamous endothelial cell thick for short diffusion pathway
large surface area for more diffusion

Question 27

what are arterioles and venules

Answer 27

smaller versions of arteries and veins that link to capillaries to provide deoxygenated/oxygenated blood

Question 28

what is tissue fluid

Answer 28

allows transport between blood and cells via diffusion

Question 29

what is hydrostatic pressure

Answer 29

generated by heart
exerted by fluid in vessels

Question 30

what is oncotic pressure

Answer 30

exerted by plasma proteins in blood
make a water potential gradient

Question 31

describe hydrostatic pressure at the arterial end of the capillary

Answer 31

higher in the arterial end than venous end
forces fluid out of capillaries through tiny gaps in capillary walls
a smaller hydrostatic pressure forces some pressure back into capillaries

Question 32

what moves with fluid in arterial end of capillaries

Answer 32

dissolved gases and nutrients

Question 33

describe oncotic pressure in the arterial end of the capillary

Answer 33

oncotic pressure means water potential of capillaries becomes more negative as hydrostatic pressure pushes blood and fluid out so water moves into capillaries down the gradient

Question 34

is hydrostatic pressure greater in the arterial end or the venous end of the capillary

Answer 34

arterial

Question 35

what happens to excess fluid in vessels

Answer 35

not all goes through capillaries, net excess is drained into vessels of lymphatic system

Question 36

what is lymph fluid

Answer 36

made in lymph nodes
contains lymphocytes which produce antibodies and remove bacteria and pathogens

Question 37

why do people with high blood pressure produce less tissue fluid

Answer 37

net outward pressure from the arteriole end increases
forces tissue fluid out of capillary
decreases net hydrostatic pressure at venous end

Question 38

how does haemoglobin behave with oxygen generally

Answer 38

it has a high affinity for oxygen
can carry 4 oxygen molecules

Question 39

how does haemoglobin behave with oxygen in the lungs

Answer 39

oxygen diffuses into plasma
then into erythrocytes
binds to haemoglobin to maintain concentration gradient

Question 40

how does haemoglobin behave with oxygen in respiring tissue

Answer 40

oxygen dissociates from oxyhaemoglobin so it can diffuse out into respiring cells

Question 41

describe the shape of the oxygen dissociation curve

Answer 41

sigmoidal as % saturation of haemoglobin is not directly proportionate to po2

Question 42

explain why the oxygen dissociation curve is shaped like that

Answer 42

hard for 1st oxygen molecule to bind due to structure of Hb
conformation then changes
after 1st oxygen molecule associates conformation changes
conformational change makes it easy for 2nd and 3rd to associate
po2 rises, gradient steepens, more o2 diffuses into Hb
more difficult to associate 4th o2 molecule as Hb gets full and gradient less steep

Question 43

what is fetal haemoglobin

Answer 43

placenta allows transfer of o2 to foetus
low po2

Question 44

describe and explain the affinity fetal haemoglobin has for oxygen

Answer 44

stronger affinity so it gets more saturated at a lower po2, meaning oxygen can dissociate from maternal Hb easily

Question 45

how is co2 transported in blood

Answer 45

5% dissolved in plasma
10% associated with Hb to make carbaminohaemoglobin
85% uses carbonic anhydrase and chloride shift to take co2 into an erythrocyte

Question 46

explain the role of carbonic anhydrase

Answer 46

co2 diffuses into erythrocyte
co2 + h2o = carbonic acid using the enzyme carbonic anhydrase

Question 47

what happens to carbonic acid in an erythrocyte after being formed

Answer 47

a hydrogen carbonate ion and a H+ proton are produced
hydrogen carbonate ion diffuses out
H+ ion is added to Hb which acts as a buffer, making haemoglobinic acid
Cl- diffuses in to counteract negative charge (chloride shift)

Question 48

what is the bohr shift

Answer 48

in a co2 rich environment, more o2 dissociates from oxyhaemoglobin
H+ reduces affinity of haemoglobin for o2 so curve goes to the right