Mass Transport In Animals

Question 1

What level of structure is haemoglobin and why

Answer 1

Quaternary as it has 4 polypeptide chains (more than one)

Question 2

Describe the structure of haemoglobin

Answer 2

2 alpha globins (apolypeptides) 2 beta globins (bpolypeptides) each of the 4 polypeptides are associated with a haem group which contains an iron ion

Question 3

How many oxygens can haemoglobin bind to and why

Answer 3

Each iron ion can combine to a single 02 so as there are 4, 4 oxygens can bind

Question 4

What is the process by which oxygen binds with haemoglobin and where does it take place

Answer 4

Association and takes place in the lungs

Question 5

The process by which haemoglobin releases o2 and where it takes place

Answer 5

Dissociation and takes place in tissues

Question 6

What does affinity refer to

Answer 6

A high affinity means 02 is associated more readily but is harder to dissociate , low affinity means less readily but dissociated more easily

Question 7

Describe the Bohr effect

Answer 7

An increased concentration of carbon dioxide at any fixed partial pressure of oxygen reduces haemoglobin’s affinity for oxygen. This means more oxygen is likely to dissociate into respiring tissues

Question 8

Why do each species have different haemoglobins

Answer 8

Each species produces haemoglobins with different amino acid sequences (primary structure) so each has a different tertiary and quaternary structure with different oxygen binding properties meaning they have higher or lower affinities

Question 9

What does the graph of the oxygen dissociation curve plot (x and y axis)

Answer 9

The saturation of haemoglobin with oxygen (%) against partial pressure of oxygen

Question 10

Describe the process of cooperative binding

Answer 10

1.the shape of haemoglobin molecule makes it difficult for fist oxygen to bind 2. The binding of the 1st 02 changes the tertiary structure of haemoglobin, causing it to change shape 3.
This change makes it easier for more oxygens to bind as it increases its affinity 4. The 4th o2 requires a higher partial pressure as probability of 4th binding is lower

Question 11

How are animals adapted to their environment by possessing different types of haemoglobin and give an example

Answer 11

Species of animals that live in a low partial pressure of oxygen environment have haemoglobin with a higher affinity for oxygen. Example is lugworm which lives in burrows covered by seawater (02 diffuses from water to blood via haemoglobin) when the tide goes out, there is no oxygenated water so haemoglobin must have a high affinity. Llama is the same as it lives in high altitudes where partial pressure is low

Question 12

What system do mammals have and what does it mean

Answer 12

Closed, double circulatory meaning all blood in confined to vessels and it passes through the heart twice

Question 13

Describe the pathway of blood through the left side of the heart

Answer 13

1. Oxygenated blood from the lungs enters the left atrium through the pulmonary vein.2. Pressure builds in the left atrium until it exceeds the pressure in the ventricles and the left AV valve (bicuspid) opens and blood flows into the left ventricle 3. When both atrium and ventricle are full, atrium contracts, forcing extra blood into the ventricles 4. Left AV valve (bicuspid) closes and ventricle contracts, forcing aortic valve open and blood passes through aorta to the body (A’ sl valve closes)

Question 14

Describe the pathway of blood through the right side of the heart

Answer 14

1. Deoxygenated blood enters the right atrium through the superior vena cava from the upper body/ inferior female cava from lower body 2. Pressure builds in the atrium until the right AV valve opens and blood flows into right ventricle 3.Right AV valve closes, ventricle contracts forcing the pulmonary tricuspid semi lunar valve open and blood passes through the pulmonary artery to the lungs (p’ SL valve closes)

Question 15

Describe diastole (relaxation of the heart)

Answer 15

1. Blood returns to the atria of the heart through the pulmonary vein (from lungs) and vena cava (from body) 2. As atria fill, the pressure in them rises, when this pressure exceeds that of ventricles, the AV valves open, allowing blood to flow into ventricles 3.muscle walls of atria+ ventricles are relaxed, causes recoil and reduces pressure in ventricle 4. This causes pressure to be lower than in aorta and pulmonary artery so aor/pulm valves in both close (dub)

Question 16

Describe atrial systole ( contraction of the atria)

Answer 16

Contraction of atrial walls, along with recoil of relaxed ventricle walls forces remaining blood into ventricles from atria

Question 17

Describe ventricular systole (contraction of ventricles)

Answer 17

1. After a short delay (to allow ventricles to fill with blood) the ventricles contract which increases pressure, decreases volume, causing AV valves shut (lub) 2. Pressure in ventricles rises further until more than in aorta or pulmonary artery and aort/pulm valves open and blood is pumped out of ventricles and into them

Question 18

How do you work out the cardiac output

Answer 18

Heart rate x stroke volume

Question 19

How is artery structure related to its function

Answer 19

Function is to transport blood under high pressure from heart to tissues 1. Muscle layer thicker compared to veins: means smaller arteries can be constricted/ dilated to control volume of blood through them 2. Elastic layer thicker than veins: as they are under high pressures so blood reaches body, elastic wall stretched and recoils (diastole and systole) which maintains pressure 3. Overall thickness is great: resists vessel bursting under pressure 4. No valves as blood under high pressure so won’t flow backward

Question 20

Arteriole structure related to function

Answer 20

Function: carry blood under lower pressure from arteries to capillaries and control flow of blood between the two 1. Muscle layer thicker than arteries: contraction of this allows constriction of lumen which constricts flow so controls movement into capillaries 2. Elastic layer thinner than arteries as blood pressure is lower

Question 21

Vein structure related to function

Answer 21

Function: transport blood slowly under low pressure from capillaries to heart 1. Thin muscle layer: because veins carry blood away from tissues so constriction/dilation doesn’t control flow to tissues 2. Thin elastic layer: as low pressure will not cause them to burst 3. Small thickness: low pressure and allows them to flatten, helping flow 4 has valves: so blood doesn’t flow back as low pressure

Question 22

Capillary structure related to function

Answer 22

Function: exchange metabolic materials between blood and rest of body (slow flow to exchange) 1. Walls are mostly lining layer: making them thin so diffusion distance short 2. Numerous and highly branched: large SA for exchange 3. Narrow diameter: so permeate tissues so no cell far/ short pathway 4. Narrow lumen so red blood cells squeezed flat against side (short distance) 5. Spaces between lining endothelial cells: allow whiteys to escape & deal w/ infection

Question 23

Describe the formation of tissue fluid

Answer 23

1. Blood pumped by the heart passes along arteries, arterioles and capillaries. Pumping creates hydrostatic pressure at the arteriole end of capillaries which causes tissue fluid to move out of blood plasma. 2. Outward pressure opposed by: hydrostatic psi of tissue fluid outside capillaries and the lower water potential of blood (due to plasma proteins) which causes water to move back into blood 3. Overall, pressure pushes tissue fluid out of capillaries at the arterial end but is only enough to force small molecules out,leaving cells and proteins in blood (ultrafiltration)

Question 24

Describe the return of tissue fluid to the circulatory system

Answer 24

once tissue fluid has exchanged metabolic materials in cells, most fluid returns to blood via capillaries: 1. Loss of tissue fluid from capillaries reduces hydrostatic psi, so when blood reaches venous end, it’s pressure is lower than surrounding tissue fluid 2. Tissue fluid is forced back into capillaries by this pressure 3. The plasma has lost water and contains proteins so has lowered W. P than fluid so water enters plasma down a W.p gradient by OSMOSIS

Question 25

How does the rest o father tissue fluid come back to the circulatory system

Answer 25

Remainder is carried back by the lymphatic system which drain their contents back to the bloodstream. They are moved by hydrostatic psi of tissue fluid that left capillaries and contraction of body muscles

Question 26

Draw out and label the structure of the heart

Answer 26

Do it and compare

Question 27

What is the innermost layer of a blood vessel called

Answer 27

Epithelium

Question 28

Explain importance of elastic fibres in the wall of the aorta

Answer 28

Stretched under high pressure (when ventricle contracts) recoils under low pressure (when ventricle relaxes) to maintains blood pressure