3.3.4.1- Mass transport in animals

Question 1

Capillaries & TF- (6)

Answer 1

1- Blood enters C from ARTERIOLES, smaller diameter results in HIGH HYDROSTATIC pressure
2- Ultrafiltration- small molecules are forced out (water, glucose, AA, fatty acids, ions, O2)
3- Large molecules remain, lowering WP
4- At venule end, low hydrostatic pressure & WP
5- Water re-enters C, via osmosis
6- Excess TF absorbed into lymphatic system

Question 2

Veins vs arteries=

Answer 2

V= deoxygenated blood> heart
A= Oxygenated blood AWAY from heart

Question 3

Right vs left ventricle=

Answer 3

R= THINNER muscular wall as blood> L, so needs to be at LOWER pressure, to prevent damage to capillaries
L= THICKER muscular wall as blood> B, so needs to be at HIGHER pressure to ensure blood reaches all cells in the body

Question 4

Arteries vs veins= (3)

Answer 4

1- A= Thicker muscle layer (so can constrict & dilate to control volume of blood, V= Thinner muscle layer
2- A=Thicker elastic layer, V=Thin elastic layer
3- A=Thicker wall, V=Thin wall

Question 5

Capillaries features-(for MF) (2)

Answer 5

1- have narrow diameter to slow blood flow (for maximal time for GE)
2- 1 cell thick- short DD

Question 6

Arteriole features= (2)

Answer 6

1- Thickest muscle layer to help RESTRICT blood flow > capillaries (so more time for GE)
2- Thinner elastic layer & walls than Artery, as lower pressure

Question 7

Cardiac output=

Answer 7

Cardiac output= heart rate x stroke volume

HR= beats of heart/ min
stroke volume= Volume of blood that leaves heart each beat (dm3)

Question 8

Cardiac cycle stages= (8)

Answer 8

1) Blood flows from L > left A, Blood flows from B> right A simultaneously
2) A contract increasing pressure in A
3) Blood is forced into the V
4) A relax & V contract
5) Pressure in V increases, shutting AV valves
6) Blood in V forced out & out of heart through pulmonary artery/ aorta
7) Blood in PA & Aorta, is at high pressure> this pressure shuts the semi-lunar valves
8) Both V & A relax & AV valves reopen

Question 9

What property of the heart allows it to contract/relax with nervous or hormonal stimulation?

Answer 9

Thick muscular layer is myogenic, only requiring O2, and never fatigues

Question 10

Key blood vessels (7)

Answer 10

1) coronary arteries (carry O2> h muscle)
2) Pulmonary artery (h>l)
3) Pulmonary vein (l>h)
4) Vena Cava (b>h)
5) Aorta (h>b)
6) Renal artery (>k)
7) Renal vein (k>)

Question 11

Benefits of double circulatory system (1+2)

Answer 11

• allows pressure of blood flow to be managed- (lower in lungs to prevent capillary damage, HIGH pressure from heart to ensure blood reaches all respiring cells in body)

Question 12

Mammalian circulatory system features= (2)

Answer 12

1) closed= blood remains within blood vessels

2) Double circulatory system= blood passes through heart TWICE in each circuit (one from blood>l) (one from l>b)

Question 13

Factors influencing type of haemoglobin

Answer 13

1) High altitude (as low pO2 in environment; h has HIGH affinity)
2) High metabolic rate (high demand for O2 in the cells; h has LOW affinity)

Question 14

What is the Bohr effect?

Answer 14

when a high CO2 conc causes the oxyhaemoglobin curve to shift to thr right;
the affinity of h>O2 decreases because CO2 changes shape of haemoglobin slightly

Question 15

What happens when the 1st O2 molecule binds to haemgolobin

Answer 15

haemoglobin undergoes a conformational change making it easier for further O2 molecules to bind

Question 16

Oxyhaemoglobin dissociation curve- overall (2)

Answer 16

• S shaped

- demonstrates increasing affinitity of hameoglobin with increasing pO2

Question 17

Oxygen & loading

Answer 17

oxygen LOADED in regions with HIGH o2 partial pressure and UNLOADED in regions of LOW o2 partial pressure

Question 18

Haemoglobin- function=

Answer 18

transport oxygen from lungs around body