Mass Transport In Animals Flashcards
1
Q
What is the haemoglobin?
A
A group of chemically similar molecules found in many different organisms
- it’s a protein w/ a quarternary structure
2
Q
Role of Haemoglobin?
A
To carry oxygen from the lungs around the body
3
Q
What is a haem group?
A
- prosthetic group that’s attached to the protein
- it contain an iron ion
4
Q
Each polypeptide chain in a haemoglobin molecule has what?
A
A haem group
5
Q
What makes haemoglobin red?
A
Iron Ion (Fe+)
6
Q
Explain disassociation
A
When red blood cells reach tissue in body (e.g. muscle cells) & oxygen is released from Oxyhaemoglobin
7
Q
Explain association
A
When oxygen binds to haemoglobin to form an oxyhemoglobin
8
Q
What are arteries?
A
Blood vessels that carry blood away from the heart & into arterioles
9
Q
What are arterioles?
A
blood vessels that are smaller arteries
- control blood flow from arteries to capillaries
10
Q
What are capillaries?
A
tiny blood vessels that link arterioles to veins
11
Q
What are veins?
A
blood vessels that carry blood from capillaries back to heart
12
Q
Describe the basic layered structure of arteries, arterioles and veins from outside inwards
A
Tough fibrous outer layer (resists pressure changes from outside & within) Muscle layer (contract & so control the flow of blood) Elastic layer (helps maintain blood pressure by recoiling) Endothelium (smooth to reduce friction & thin to allow diffusion) Lumen (NOT a layer) central cavity of blood vessel through which blood flows
13
Q
Function of the artery?
A
- to transport blood rapidly under high pressure from heart to tissue
14
Q
Structure of artery?
A
- muscle layer thick compared to veins
- no valves (except in arteries leaving heart)
- overall thick wall
- elastic layer thick compared to veins
15
Q
How does a thick muscle layer make the artery related to its function?
A
- means smaller arteries can be constricted & dilated to control volume of blood passing through them
16
Q
Why does the artery have no valves?
A
- blood is under high pressure due to heart pumping blood into arteries therefore tends not to flow backwards
17
Q
How does a thick wall make the artery related to its function?
A
resists vessel bursting under high pressure
18
Q
How does a thicker elastic layer than veins make the artery related to its function?
A
- because it’s important blood pressure in arteries is kept high so blood can reach extremities of the body
- elastic wall stretched at each beat of the heart (systole) then springs back & relaxes (diastole) like an elastic band
- stretching & recoil action helps maintain high pressure & smooth pressure surges created by beating of the heart
19
Q
What is the endothelium?
A
- cells that line the interior surface of blood vessels and lymphatic vessels
20
Q
What is the function of the arterioles?
A
- carry blood, at low pressure from arteries to capillaries, they also control blood flow between them
21
Q
Structure of the arterioles?
A
- muscle layer thicker than in arteries
- elastic layer thinner than in arteries
22
Q
How does a thin elastic layer make arterioles related to their function?
A
- because blood pressure is low
23
Q
How does a thick muscle layer make arteriole related to its function?
A
- contraction of muscle layer allows constriction of the lumen of the arteriole
- this restricts the blood flow & so controls its movement into capillaries that supply the tissues with blood
24
Q
Function of veins?
A
- transport blood slowly, under low pressure from capillaries in tissues to heart
25
Structure of the veins
- muscle layer thin (compared to arteries)
- elastic layer thin (compared to arteries)
- overall thickness of wall small
- valves at intervals throughout
26
How does a thin muscle layer make veins related to their function?
- veins carry blood away from tissues and therefore their constriction & dilation cannot control flow of blood to tissues
27
How does a thin elastic layer make veins related to their function?
- because low pressure of blood within the veins won't cause them to burst & pressure is too low to create recoil action
28
How does a small thickness of walls make veins related to their function?
- no need for thick walls because pressure in veins too low to cause bursting
- allows them to be flattened easily, aiding blood flow within them
29
How do valves at intervals throughout make the veins related to their function?
- to ensure blood doesn't flow backwards, which it could because pressure is low
- when body muscles contract, veins are compressed, pressurising blood within them
- valves ensure pressure directs blood in 1 direction: to the heart
30
Function of capillaries?
- exchange metabolic material (e.g. oxygen, carbon dioxide & glucose) between blood & cells of the body
- flow of blood in capillaries is much slower (allows more time for the exchange of material)
31
How does walls consisting mainly of lining layer make the capillary related to its function?
- extremely thin so DD is short
| - allows for rapid diffusion of materials between blood and cells
32
How does a narrow lumen make the structure of the capillaries well-related to their functions?
- so that red blood cells are squeezed flat against side of capillary
- brings them closer to the cells to which they supply oxygen. Reduces DD.
33
How does being numerous and highly branched make the capillary related to its function?
- provides a large SA for exchange
34
How does a narrow diameter make the capillary related to its function?
- so permeate tissues
| no cells are far from capillary & there's a short DD
35
How does no spaces between endothelial cells make the capillary related to its function?
- allows WBCs to escape to deal with infections within tissues
36
What is association?
Oxygen binds to haemoglobin to form oxyhaemoglobin
37
What kind of protein is a haemoglobin?
- made up of 4 different polypeptide chains
| - gives it a quarternary structure
38
Define affinity and its role in forming the oxyhaemoglobin
- attraction
- haemoglobin has a high affinity for oxygen
- when RBC reaches lungs, oxygen diffuses into RBC & binds to haemoglobin
- four molecules of O2 bind to 1 of haemoglobin
- oxyhaemoglobin formed
39
What is oxygen partial pressure?
pO2
| - conc of oxygen in cells
40
What is carbon dioxide partial pressure?
pCO2
| - conc of carbon dioxide in cells
41
What does high pO2 mean?
- means haemoglobin has a high affinity for oxygen & oxygen binds to haemoglobin
42
What does a low pO2 mean?
- means haemoglobin has a low affinity for oxygen & oxygen disassociates from haemoglobin
43
Effect of oxygen partial pressure on the affinity of haemoglobin?
- allows oxygen to be transported to cells it's needed most
| - from lungs (high conc) to respiring tissues (where it's limited)
44
Adaptation of haemoglobin of animals at HIGH ALTITUDES
- their haemoglobin has a high affinity for oxygen
| - because air at higher altitudes have much lower oxygen partial pressure of oxygen than at sea level
45
Adaptation of haemoglobin of animals with HIGH METABOLIC RATES
- have haemoglobin that dissociates from oxygen easily
| - allows oxygen to be quickly and easily supplied to cells for use in respiration
46
Shape of curve on graph with the relationship between % saturation of haemoglobin & oxygen partial pressure of surrounding tissue
S-shaped
47
Name of curve on graph showing the relationship between % saturation of haemoglobin & oxygen partial pressure of surrounding tissue
Dissociation curve
48
Explain the dissociation curve
Low pO2 - when oxygen partial pressure is low haemoglobin has a low affinity for oxygen. % saturation low because O2 dissociates from haemoglobin
Increasing pO2 - affinity of haemoglobin for O2 increases slightly. When 1st molecule of O2 binds to haemoglobin, the protein undergoes a CONFORMATIONAL CHANGE
(Change in shape allows other O2 to bind more easily, % saturation of haemoglobin increases quickly)
Plateau in % saturation
- as more O2 molecules bind to haemoglobin, it becomes more difficult for O2 molecules to bind
49
What way does dissociation curve shift at higher affinity levels?
Left
50
What way does dissociation curve shift at lower affinity levels?
Right
51
What is the bohr effect?
the pCO2 also influences affinity of haemoglobin for oxygen
52
Partial pressures of respiring cells?
- use O2 in respiration so have low O2 & produce CO2 so have high CO2
53
What happens when pCO2 is high?
rate of oxygen dissociation increases
54
What does increased dissociation of oxygen do to oxyhaemoglobin dissociation curve?
- shift to right which means oxygen will dissociate from haemoglobin at lower oxygen partial pressure than normal
55
Complex multicelluar organisms require what?
specialised system for transporting nutrients throughout their bodies & removing waste products
56
Heart is where in the circulatory system?
The CENTRE
57
Mammals have what kind of circulatory system?
A double circulatory system (Blood flows through heart twice in 1 circuit)
58
describe the advantage of the bohr effect during intense exercise [2 Marks]
- increases dissociation/unloading of oxygen
| - for aerobic respiration at tissues/muscles/cells
59
explain the importance of elastic fibres in the wall of the aorta [2 Marks]
- allows for recoil/stretch to smooth blood flow/maintain high blood pressure
60
Explain the importance of muscle fibres in the wall of an arteriole
- muscle contracts
| - reduces/regulates blood flow (to capillaries)
61
Efficient exchange of substances in the capillaries is linked to the rate of blood flow. Explain how
- more time for exchange of substances
