topic 3.1.2: transport in animals

Question 1

what is hydrostatic pressure?

Answer 1

created when blood is pumped along vessels

Question 2

what is oncotic pressure?

Answer 2

pressure exerted by proteins (albumins) in blood plasma

Question 3

how are tissue fluid and lymph formed?

Answer 3

H pressure forces blood out of caps, only nutrients and oxygen get through
O pressure forces some fluid back in
water potential in tissue fluid is less negative than blood, so water moves into blood
remaining tissue fluid drains into lymphatic system

Question 4

describe the cardiac cycle

Answer 4

atrial systole: atria contract, AV valves open, blood enters ventricles
ventricular systole: ventricles contract, AV valves shut, SL valves open, blood leaves ventricles
cardiac diastole: atria and ventricles relax, pressure lowers, blood drawn from vessels, SL valves shut

Question 5

what does myogenic mean?

Answer 5

heart can initiate its own contraction

Question 6

how is heart action initiated and coordinated?

Answer 6

sinoatrial node initiates wave of electrical stimulation which causes atria to contract
atrioventricular node passes wave to Purkyne fibres at apex of heart, causing ventricles to contract

Question 7

describe a diagram of an ECG

Answer 7

atrial systole: P (small peak)
ventricular systole: Q (small dip) R (tall peak) S (taller dip)
diastole: T (smooth hump)

Question 8

describe the structure of Hb

Answer 8

water soluble globular protein, 2 alpha and 2 beta polypeptide chains each with haem group, can carry 4 O2s

Question 9

what is partial pressure?

Answer 9

a measure of concentration- higher concentration of O2 in cells means higher partial pressure

Question 10

describe the role of Hb in transporting O2

Answer 10

higher partial pressure of O2 means Hb has higher affinity for O2
O2 binds to Hb in lungs
during respiration O2 is used up so partial pressure decreases
O2 released into tissues

Question 11

how does Hb saturation affect its affinity for O2

Answer 11

Hb changes shape when it binds to O2 to increase affinity

Question 12

what is the Bohr effect?

Answer 12

CO2 reduces partial pressure of O2 so reduces affinity, meaning it is released
in respiring tissues CO2 is released thus so is O2

Question 13

what are the 3 ways that CO2 is transported?

Answer 13

1) dissolved in plasma
2) bound to Hb as carbaminohaemoglobin (in RBCs)
3) most enters RBCs and turns into hydrogen carbonate ions

Question 14

how is CO2 turned into HCl-?

Answer 14

-respiring tissues have a high partial pressure of CO2
-CO2 and water make carbonic acid (catalysed by carbonic anhydrase)
dissociates into H+ and HCO3-
-H+ binds to Hb to form haemoglobinic acid so releases O2 (prevents blood from becoming acidic)
-HCO3- swapped for Cl- to maintain charge

Question 15

differences between fetal and adult Hb

Answer 15

F Hb has a higher affinity for O2 so O2 dissociates from mother’s Hb
F Hb has a steeper dissociation curve

Question 16

describe the adaptations of arteries

Answer 16

collagen, elastic fibres, thick smooth muscle layer

Question 17

describe the adaptations of arterioles

Answer 17

smaller than arteries but with a comparatively larger lumen, more smooth muscle and less elastin

Question 18

describe the adaptations of capillaries

Answer 18

narrow lumen, thin walls, highly branched

Question 19

describe the adaptations of veins

Answer 19

collagen, little smooth muscle and elastin, valves

Question 20

describe the adaptations of venules

Answer 20

smaller than veins

Question 21

describe the movement of blood through the heart

Answer 21

body, vena cava, right atrium, AV valve, right ventricle, SL valve, pulmonary artery, pulmonary vein, left atrium, AV valve, left ventricle, SL valve, aorta

Question 22

which side of the heart pumps oxygenated blod?

Answer 22

left

Question 23

what is the aorta’s role?

Answer 23

moves O blood from left ventricle to body

Question 24

what is the vena cava’s role?

Answer 24

moves deO blood from body to right atrium