transport in animals

Question 1

name features of good transport systems

Answer 1

fluid- to carry substances around body
pump to create pressure to move fluid
exchange surfaces enable substances to leave and enter blood

Question 2

what are difference between single and double circulatory systems

Answer 2

single

• blood through heart once per circuit
• first capillary network in gills=slow for much gas exchange of O2 + CO2
• 2nd in body= slow + low pressure exchange of substances
• body temp= water temp
• body supported by water

double

• through heart twice
• high pressure so rapid delivery of 02 and nutrients
• pulmonary circulation at low pressure as to not damage lungs
• very active= high metabolic demands

Question 3

what is Ficks law affecting rate of diffusion

Answer 3

rate of diffusion= SA x difference in conc /thickness of exchange surface

ROD= SAD/TOES

Question 4

what happens when levels of 02 are high/low

Answer 4

high- alveoli takes up O2

low- retiring tissues release O2

Question 5

describe cooperative binding

Answer 5

first O2 mol binds slowly
causes shape of HB mol to change
much easier for 2nd and 3rd to bind to their harm groups
4th O2 mol binds slowly

Question 6

what is myoglobin

Answer 6

respiratory pigment in muscle
provides emergency store of O2
very stable-wont release until levels re very low
high affinity of O2 than HB

Question 7

name structural composition of blood vessels

Answer 7

collagen
-structural support

elastic fibres

• composed of elastin
• stretch + recoil
• give walls flexibility

smooth muscle
-contracts and relaxes to change size of lumen

Question 8

describe the structure and function of arteries

Answer 8

carry oxygenated blood away from heart 
-pulmonary artery carries deoxygenated blood away from heart
high pressure
lots of elastic fibres and smooth muscle
linked to capillaries by arterioles

Question 9

how re capillaries adapted to their function

Answer 9

provide large SA for substance diffusion
think walls- 1 endothelial cel thick
slow blood flow= more time

Question 10

what is oncotic pressure

Answer 10

plasma proteins give capillaries relatively high solute potential compares to surrounding fluid
water has tendency to move into blood from surrounding fluid
(by OSMOSIS)

Question 11

what is hydrostatic pressure

Answer 11

pressure of blood from heart contractions

Question 12

how is tissue fluid formed

Answer 12

at arterial end of capillaries
-hydrostatic pressure>oncotic pressure so fluid is squeezed out
same composition of plasma
-no RBCs or plasma proteins
at venous end
-hydrostatic pressure< oncotic pressure so water moves back in
-90% back in once blood reaches veins

Question 13

how is lymph formed

Answer 13

10% of tissue fluid drains into lymph capillaries
lymph capillaries join to form large vessels with valves
fluid transported through squeezing of muscles
lymph vessels contain lymph nodes which intercept bacteria

Question 14

what re the stages of the cardiac cycle

Answer 14

diastole

• heart relaxes
• volume + pressure increases
• atria fill ventricles with blood
• blood pressure in arteries low

systole

• atrial and ventricles contracts (systoles)
• pressure in heart increases
• pressure in arteries is high

Question 15

which side of the heart does deoxygenated blood flow through

Answer 15

right

Question 16

describe the structure and function of atria

Answer 16

thin walls
as blood flows in, atrioventricular valves open
contract when A+ V both filled with blood
av valves prevent back flow
-tendinous cords prevents valves being turned inside out

right atrium

• deoxygenated blood enters from vena cava at low pressure
• tricuspid valve

left atrium

• oxygenated blood enters from pulmonary vein
• bicuspid valve

Question 17

describe the structure and function on vesicles

Answer 17

pump blood through semilunar valves
empty together
septum divides them

right ventricle
-pumps blood into pulmonary artery

left
-thicker walls

Question 18

how is the basic rhythm of the heartbeat controlled

Answer 18

wave of electric excitation at Sino-atrial node (SAN)

• causes atria to contract
• layer of non conducting tissue prevents wave spreading to ventricles

electrical activity of SAN picked up by atrocities-ventricular node (AVN)
-imposes delay before stimulating bundle of His

bundle of His

• bundle of conducting tissue made up of purkinje fibres which run through septum
• fibres spread out at ventricle walls
• excitation triggers contraction of ventricles
• contraction starting at apex allows more efficient emptying