3.3.4.1 Mass Transport in animals (Unit 3 Exchange)

Question 1

Give some ways in which cardiac output is increased during vigorous exercise

Answer 1

Increased heart rate
Increased stroke volume
More adrenaline

Question 2

Explain what causes the blood pressure in the aorta to be higher than the blood pressure in the pulmonary artery

Answer 2

Left ventricle has thicker muscle

Question 3

Explain why a vein is described as an organ

Answer 3

It’s made of tissue

Question 4

Explain how the elastic tissue helps even out the pressure of the blood going through the arteries

Answer 4

Elastic tissue stretches when pressure gets too high

And recoils when pressure returns to normal

Question 5

The Cardiac cycle is controlled by the sinoatrial node (SAN) and the atrioventricular node (AVN). Describe how

Answer 5

The SAN initiates heartbeat
SAN sends waves of electricity across the atria causing atrial contraction
AVN delays to allow the atria to empty (and the ventricles to fill up) before the ventricles contract
AVN them sends a wave of electrical impulses down “bundle of His”
This causes the ventricles to contract from the base up (ventricular systole)

Question 6

An increase in respiration in the tissues of a mammal affects the oxygen dissociation curve of haemoglobin. Describe and explain how

Answer 6

Increase in carbon dioxide so the curve moves to the right

Question 7

People living in high altitudes have more red blood cells than people living at sea level l. Explain the advantage of this to people living at high altitudes

Answer 7

They will have more haemoglobin so can pick up more oxygen in the lungs

Question 8

Explain how having a low protein diet can result in the accumulation of tissue fluid

Answer 8

The water potential in the capillaries is not as low as it is in a protein rich diet
So more tissue fluid is formed at the arteriole end and less water is absorbed into the capillaries (at the venular end) by osmosis

Question 9

Explain ways in which the composition of tissue fluid differs from that of blood plasma

Answer 9

Tissue fluid contains little protein (as protein molecules are too large to pass through the capillary walls)
Tissue fluid contains less glucose as some of the glucose will have entered tissue cells

Question 10

Explain how fluids leave the capillaries at the arterial end

Answer 10

Hydrostatic pressure is greater than the osmotic effect so molecules are forced out

Question 11

Explain the meaning of the term atheroma

Answer 11

A fatty deposit forming in cells in the artery wall

Question 12

Explain why atheroma may lead to a blood clot

Answer 12

The fatty substance narrows the arteries

This results in an uneven flow of blood and can damage the endothelium

Question 13

Explain how the shape of a red blood cell allows it to take up a large amount of oxygen in a short time

Answer 13

It’s has a large surface area to volume ratio for diffusion

It is flat and thin so oxygen can reach all haemoglobin rapidly

Question 14

Describe how the increase in pressure of the blood in the arteries is a result from the events in the cardiac cycle

Answer 14

Increase in blood pressure caused by blood leaving the heart and entering the arteries
This is a result of ventricular systole

Question 15

Describe the part played by proteins in the plasma in returning tissue fluid to the capillaries

Answer 15

A high concentration of protein produces a lower water potential so water moves into the capillaries by osmosis

Question 16

Give some changes that will increase blood flow through the skeletal muscles

Answer 16

Increase in heart rate
Increased volume of blood pumped per beat
Dilation of vessels
Increased blood pressure

Question 17

Explain some advantages of increasing the blood flow through the skeletal muscles during exercise

Answer 17

More oxygen supplied for respiration so less anaerobic respiration
More glucose supplies for respiration
Carbo dioxide rapidly removed from respiring cells

Question 18

Describe how the regular contractions of the atria and the ventricles is initiated and coordinated by the heart itself

Answer 18

Cardiac muscle is myogenic
SAN sends a wave of electrical impulses across the atria
This initiates the contraction of the atria
AVN then spreads an electrical signal across the ventricles causing the ventricles to contract once they have filled with blood

Question 19

During exercise the oxygen dissociation curve moves tot the right. Explain the advantage of this

Answer 19

Haemoglobin releases more oxygen for respiration

Question 20

Describe how haemoglobin loads and unloads oxygen in the body

Answer 20

Haemoglobin picks up oxygen at high partial pressures e.g. In the lungs
Haemoglobin unloads oxygen at low partial pressures e.g. In respiring tissues

Question 21

Explain how the structure of arterioles enables the regulation of blood flow to different parts of the body

Answer 21

Muscles in the walls for the arterioles contact increasing blood flow

Question 22

When is the arterial pressure at its maximum value?

Answer 22

When the ventricles are contracting

Question 23

If the oxygen dissociation curve is further to the left it means the haemoglobin has a _____________ affinity for oxygen

Answer 23

Greater

Question 24

If the oxygen dissociation curve is further to the right it means the haemoglobin has a _____________ affinity for oxygen

Answer 24

Lower

Question 25

the hydrostatic pressure falls from the arteriole end of the capillary to the venuole end - why?

Answer 25

loss of fluid/water

Question 26

give 2 ways the structure of the fishes gills are adapted for gas exchange

Answer 26

many lamellae/filaments so a large SA

thin so a short diffusion pathway

Question 27

How does the countercurrent flow in fish ensure max amount of oxygen passes into the blood flowing through the gills?

Answer 27

1. water and blood flow opposite directions
2. blood always meets water with a higher concentration of oxygen
3. diffusion gradient maintained across the full length of the gill

Question 28

give 2 ways the aorta structure is suited to function

Answer 28

1. Elastic tissue - stretch and recoil /spring back
2. muscle layer for contraction
3. Thick walls to resist pressure and stop it bursting
4. smooth endothelium - reduces friction
5. semi lunar valve - prevents back flow

Question 29

How is an insects tracheal system adapted for gas exchange?

Answer 29

1. tracheoles thin walls SO short diffusion distance
2. highly branched so short diffusion distance
3. highly branched so a large surface area
4. abdonimal pumping to move air SO maintains concentration gradient

Question 30

Role of the heart in TF formation?

Answer 30

contraction produces a high pressure

This forces WATER (and dissolve substances) out of the capillaries

Question 31

Blockage of lymphatic system could cause lymphodema - HOW?

Answer 31

prevents EXCESS TF from returning

Question 32

name the blood vessels that carry blood to the heart muscle

Answer 32

coronary arteries

Question 33

binding of one molecule of oxygen to Hb makes it easier for a second oxygen to bind - why?

Answer 33

1. binding of the 1st changes to tertiary structure

2, uncovering 2nd binding site