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Mammal body Flashcards

1
Q

Mass transport

A

bulk movement of gases or liquids in one direction, usually via a system of vessels and tubes

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2
Q

What is the primary need for a circulatory system in larger organisms?

A

To provide a constant supply of reactants for metabolism, such as oxygen and glucose.

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3
Q

How do single-celled organisms obtain oxygen and glucose?

A

Directly from their surroundings through diffusion.

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4
Q

What is the main problem larger organisms face regarding diffusion?

A

The diffusion distances involved are too great.

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5
Q

What is mass transport system [2]

A

1) The digestive system is connected to the circulatory system
2) The lungs are connected to the circulatory system

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6
Q

What is a closed circulatory system?

A

A system where blood is pumped around the body and always contained within a network of blood vessels.

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7
Q

Which organisms have closed circulatory systems?

A

All vertebrates and many invertebrates.

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8
Q

What is an open circulatory system?

A

A system where blood is not contained within blood vessels but is pumped directly into body cavities.

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9
Q

Which organisms have open circulatory systems?

A

Organisms such as arthropods and molluscs.

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10
Q

What type of circulatory system do humans have?

A

A closed double circulatory system.

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11
Q

What does the right side of the heart do in the pulmonary circulatory system?

A

Pumps deoxygenated blood to the lungs for gas exchange.

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12
Q

What is the function of the left side of the heart in the systemic circulatory system?

A

Pumps oxygenated blood efficiently around the body at high pressure.

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13
Q

What is the function of the heart [2]

A

1) A hollow, muscular organ that pumps blood.
2) Cardiac muscle tissue is specialised for repeated involuntary contraction without rest.

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14
Q

What are arteries [2]

A

1) Blood vessels that carry blood away from the heart.
2) The walls of the arteries contain lots of muscle and elastic tissue and a narrow lumen, to maintain high blood pressure.

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15
Q

What is the diameter range of arteries?

A

0.4 - 2.5 cm.

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16
Q

What are arterioles?

A

Small arteries that branch from larger arteries and connect to capillaries.

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17
Q

What is the diameter of arterioles?

A

Around 30 μm.

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18
Q

What are capillaries [2]

A

1) Tiny blood vessels that connect arterioles and venules.
2) Their size means they pass directly past cells and tissues and perform gas exchange and exchange of substances such as glucose.

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19
Q

What is the diameter of capillaries?

A

5-10 μm.

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20
Q

What are venules?

A

Small veins that join capillaries to larger veins.

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21
Q

What is the diameter range of venules?

A

7 μm - 1 mm.

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22
Q

What are veins [3]

A

1) Blood vessels that carry blood back towards the heart.
2) The walls of veins are thin in comparison to arteries, having less muscle and elastic tissue but a wider lumen.
3) Valves help maintain blood flow back towards the heart.

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23
Q

What structural differences exist between arteries and veins?

A

Veins have thinner walls, less muscle and elastic tissue, and a wider lumen compared to arteries.

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24
Q

True or False: All organisms that respire aerobically only need to transport oxygen.

A

False. Blood transport other substances as well.

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25
What should you do carefully during exams regarding circulatory diagrams?
Distinguish between single and double circulatory systems and discern between pulmonary and systemic circulation.
26
Pathway of blood explained
Draw it out
27
What does the oxygen dissociation curve show?
The rate at which oxygen associates and dissociates with haemoglobin at different partial pressures of oxygen (pO2).
28
What is partial pressure of oxygen?
It refers to the pressure exerted by oxygen within a mixture of gases; it is a measure of oxygen concentration.
29
When is haemoglobin considered saturated?
When all of its oxygen binding sites are taken up with oxygen, meaning it contains four oxygen molecules.
30
What does haemoglobin's affinity for oxygen describe?
The ease with which haemoglobin binds and dissociates with oxygen.
31
What happens when haemoglobin has a high affinity for oxygen?
It binds easily and dissociates slowly.
32
What happens when haemoglobin has a low affinity for oxygen?
It binds slowly and dissociates easily.
33
How does oxygen behave in other liquids like water compared to haemoglobin?
In water, oxygen associates at a constant rate, providing a straight line on a graph, while with haemoglobin, oxygen binds at different rates as pO2 changes, resulting in a curve.
34
How does haemoglobin's affinity for oxygen change?
It changes at different partial pressures of oxygen.
35
What does the oxygen dissociation curve indicate when read from left to right?
It provides information about the rate at which haemoglobin binds to oxygen at different partial pressures of oxygen.
36
What happens to oxygen binding at low pO2?
Oxygen binds slowly to haemoglobin, leading to low saturation percentage.
37
What is the affinity of haemoglobin for oxygen at low pO2?
Haemoglobin has a low affinity for oxygen at low pO2.
38
What occurs at medium pO2 on the oxygen dissociation curve?
Oxygen binds more easily to haemoglobin, causing a rapid increase in saturation.
39
What is the effect of a small increase in pO2 at medium pO2?
only has a small effect on the percentage saturation of haemoglobin; this is because most oxygen binding sites on haemoglobin are already occupied
40
What happens at high pO2?
Oxygen binds easily to haemoglobin, allowing for saturation as blood passes through the lungs.
41
What is the affinity of haemoglobin for oxygen at high pO2?
Haemoglobin has a high affinity for oxygen at high pO2.
42
What is the effect of increasing pO2 at high pO2?
Increasing pO2 by a large amount has a small effect on the percentage saturation of haemoglobin.
43
What does the oxygen dissociation curve indicate when read from right to left?
It provides information about the rate at which haemoglobin dissociates with oxygen at different partial pressures of oxygen.
44
What occurs in the lungs where pO2 is high?
There is very little dissociation of oxygen from haemoglobin.
45
What happens at medium pO2 regarding oxygen dissociation?
Oxygen dissociates readily from haemoglobin, which is important for cellular respiration.
46
What is the effect of a small decrease in pO2 at medium pO2?
A small decrease in pO2 causes a large decrease in percentage saturation of haemoglobin.
47
What happens at low pO2 regarding dissociation?
Dissociation slows as there are few oxygen molecules left on the binding sites.
48
What explains the shape of the oxygen dissociation curve?
The shape of the haemoglobin molecule makes it difficult for the first oxygen molecule to bind.
49
What occurs after the first oxygen molecule binds to haemoglobin?
Haemoglobin changes shape, making it easier for subsequent oxygen molecules to bind.
50
What is cooperative binding?
The shape change of haemoglobin that leads to easier oxygen binding.
51
What happens as haemoglobin approaches saturation?
It takes longer for the fourth oxygen molecule to bind due to a shortage of remaining binding sites.
52
Draw the graph of oxygen dissociation for high affinity of oxygen and low affinity of oxygen compared to normal
53
What waste product is produced during respiration?
Carbon dioxide is produced during respiration.
54
How does waste carbon dioxide move from tissues to the blood?
Waste carbon dioxide diffuses from the tissues into the blood.
55
What is the primary way carbon dioxide is transported in the blood?
Around 85% of carbon dioxide is transported in the blood plasma in the form of hydrogen carbonate ions (HCO3-).
56
What percentage of carbon dioxide dissolves directly in the blood plasma?
Around 5% of carbon dioxide dissolves directly in the blood plasma.
57
How is the remaining carbon dioxide transported in the blood?
About 10% of carbon dioxide is bound to haemoglobin as carbaminohaemoglobin.
58
59
What waste product is released from respiring cells?
Carbon dioxide is released as a waste product from respiring cells.
60
What happens to carbon dioxide inside red blood cells?
Carbon dioxide combines with water to form H2CO3.
61
What is the chemical equation for the reaction of carbon dioxide and water?
CO2 + H2O ⇌ H2CO3
62
What enzyme is present in red blood cells that catalyzes the reaction between carbon dioxide and water?
Red blood cells contain the enzyme carbonic anhydrase.
63
What happens to the reaction between carbon dioxide and water without carbonic anhydrase?
The reaction proceeds very slowly without carbonic anhydrase.
64
Why does H2CO3 form more slowly in plasma than in red blood cells?
The plasma contains very little carbonic anhydrase.
65
What does carbonic acid dissociate into?
Carbonic acid dissociates into hydrogen ions (H+) and hydrogen carbonate ions (HCO3-).
66
What is the chemical equation for the dissociation of carbonic acid?
H2CO3 ⇌ HCO3– + H+
67
What role does haemoglobin play in relation to hydrogen ions?
Haemoglobin can combine with hydrogen ions, forming haemoglobinic acid and preventing the H+ ions from lowering the pH of the red blood cell.
68
How is haemoglobin described in the context of hydrogen ions?
Haemoglobin is said to act as a buffer.
69
What happens to hydrogen carbonate ions after they are formed?
Hydrogen carbonate ions diffuse out of the red blood cells into the plasma to be transported in solution.
70
What is the Bohr effect?
Changes in the oxygen dissociation curve as a result of carbon dioxide levels.
71
What happens to haemoglobin's affinity for oxygen when CO2 levels are high?
Haemoglobin’s affinity for oxygen is reduced.
72
In which tissues does the Bohr effect occur?
In respiring tissues, where cells produce carbon dioxide as a waste product of respiration.
73
How does CO2 affect the pH of the blood?
CO2 lowers the pH of the blood.
74
What does CO2 combine with to form carbonic acid?
CO2 combines with water.
75
What does carbonic acid dissociate into?
Hydrogen carbonate ions and hydrogen ions.
76
What effect do hydrogen ions have on haemoglobin?
Hydrogen ions bind to haemoglobin, causing the release of oxygen.
77
Why is the Bohr effect beneficial?
It allows haemoglobin to give up its oxygen more readily in respiring tissues where it is needed.
78
What happens to the dissociation curve when CO2 levels increase?
The curve shifts to the right.
79
What does a rightward shift in the dissociation curve indicate [2]
1) At any given partial pressure of oxygen, the percentage saturation of haemoglobin is lower at higher levels of CO2. 2)because increase in pH dissociates the oxygen faster, less oxygen molecules can bind to the haemoglobin therefore saturation is lower
80
What is the Bohr effect?
Changes in the oxygen dissociation curve as a result of carbon dioxide levels.
81
What happens to haemoglobin's affinity for oxygen when carbon dioxide levels are high?
Haemoglobin’s affinity for oxygen is reduced.
82
In which tissues does the Bohr effect primarily occur?
In respiring tissues where cells produce carbon dioxide as a waste product.
83
How does carbon dioxide affect the pH of the blood?
CO2 lowers the pH of the blood.
84
What does CO2 combine with to form carbonic acid?
CO2 combines with water.
85
What does carbonic acid dissociate into?
Hydrogen carbonate ions and hydrogen ions.
86
What effect do hydrogen ions have on haemoglobin?
Hydrogen ions bind to haemoglobin, causing the release of oxygen.
87
Why is the release of oxygen by haemoglobin in respiring tissues beneficial?
It means that haemoglobin gives up its oxygen more readily where it is needed.
88
What happens to the dissociation curve when CO2 levels increase?
The curve shifts to the right.
89
What does a rightward shift in the dissociation curve indicate?
At any given partial pressure of oxygen, the percentage saturation of haemoglobin is lower at higher levels of CO2.
90
Draw a graph for the bohr effect
91
What does myogenic mean in relation to the heartbeat?
Myogenic means the heart will beat without any external stimulus.
92
What is the intrinsic rhythm of the heart?
The intrinsic rhythm means the heart beats at around 60 times per minute.
93
What is the sinoatrial node (SAN)?
The SAN is a group of cells in the wall of the right atrium that initiates a wave of depolarisation causing the atria to contract.
94
What is the function of the Annulus fibrosus?
The Annulus fibrosus is a region of non-conducting tissue that prevents depolarisation from spreading straight to the ventricles.
95
Where is depolarisation carried after the Annulus fibrosus?
Depolarisation is carried to the atrioventricular node (AVN).
96
What is the atrioventricular node (AVN)?
The AVN is a region of conducting tissue between the atria and ventricles.
97
What happens after the AVN is stimulated?
After a slight delay, the AVN passes the stimulation along the bundle of His.
98
Why is there a delay after the AVN is stimulated?
The delay means that the ventricles contract after the atria.
99
What is the bundle of His?
The bundle of His is a collection of conducting tissue in the septum of the heart that divides into two conducting fibres called Purkyne tissue.
100
What do the Purkyne fibres do?
The Purkyne fibres spread around the ventricles and initiate the depolarization of the ventricles from the apex of the heart.
101
What is the result of the ventricles contracting?
The contraction of the ventricles forces blood out of the pulmonary artery and aorta.
102
Stages in the cardiac cycle [6]
1) Sinotrial node sends out wave of excitation 2) Atria contracts, also named atrial systole 3) Atrioventricular node sends out wave of excitation 4) Purkye tissues conducts wave of excitement 5) Ventricles contract

AS BIO (10 decks)

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