Mass Transport In Animals Flashcards
1
Q
What type of tissue makes up the wall of veins and arteries?
A
Endothelium
2
Q
What feature allows veins to prevent the backflow of blood?
A
Pocket valves.
3
Q
How does the thickness of artery walls compare to vein walls?
A
Artery walls are thicker than vein walls.
4
Q
What is the function of elastic tissue in arteries?
A
It helps maintain blood pressure by allowing the arteries to stretch and recoil.
5
Q
What is the difference between the structure of veins and arteries?
A
Veins have thinner walls and wider lumens compared to arteries, which have thick, muscular walls.
6
Q
What is the significance of capillaries having thin walls?
A
It allows for efficient exchange of substances between blood and tissues.
7
Q
Why does a double circulatory system make oxygen delivery more efficient?
A
Blood passes through the heart twice per cycle, maintaining higher pressure and faster flow.
8
Q
What is the main advantage of a closed circulatory system?
A
Blood is contained within vessels, which maintains higher pressure for faster delivery of oxygen and nutrients.
9
Q
Identify the artery and vein in a cross-section of the heart.
A
Artery has a narrow lumen and thick walls; vein has a wider lumen and thin walls.
10
Q
What structure prevents backflow of blood into the heart chambers?
A
Valves
11
Q
What side of the heart pumps blood to the lungs?
A
Right
12
Q
What is the function of the left ventricle?
A
To pump oxygenated blood to the rest of the body.
13
Q
What is the role of septum in the heart?
A
It separates the right and left sides of the heart to prevent mixing of oxygenated and deoxygenated blood.
14
Q
Why are the walls of the left ventricle thicker than the right ventricle?
A
The left ventricle pumps blood at a higher pressure to the entire body.
15
Q
What are the functions of the atria in the heart?
A
To receive blood returning to the heart and pump it into the ventricles.
16
Q
Name two advantages of a double circulatory system.
A
Maintains higher blood pressure and allows faster oxygen delivery.
17
Q
What is the main characteristic of capillaries that aids in gas exchange?
A
Their walls are only one cell thick.
18
Q
What are the key features of arteries?
A
Thick walls, narrow lumen, high pressure, no valves.
19
Q
What are the key features of veins?
A
Thin walls, wide lumen, low pressure, contains valves.
20
Q
What are the key features of capillaries?
A
Very thin walls (one cell thick), tiny lumen, and they connect arteries to veins.
21
Q
Why do arteries not have valves?
A
Blood in arteries is under high pressure, which prevents backflow.
22
Q
What system does a fish have for circulation?
A
single circulatory system.
23
Q
What is the difference between a single and double circulatory system?
A
In a single system, blood passes through the heart once per circuit; in a double system, it passes through the heart twice per circuit.
24
Q
What is the main role of the vena cava?
A
To carry deoxygenated blood from the body to the right atrium.
25
What is the main role of the pulmonary vein?
To carry oxygenated blood from the lungs to the left atrium.
26
What is the function of the aorta?
To carry oxygenated blood from the left ventricle to the rest of the body.
27
What is the function of the pulmonary artery?
To carry deoxygenated blood from the right ventricle to the lungs.
28
What are two differences between fish and mammal circulatory systems?
Fish have a single circulatory system with lower blood pressure; mammals have a double circulatory system with higher pressure.
29
What prevents backflow of blood in veins
Pocket valves
30
How do capillaries facilitate efficient gas exchange?
They have thin walls and a large surface area.
31
What is the main role of the heart’s septum
To separate oxygenated and deoxygenated blood
32
Why does blood pressure drop when blood reaches the capillaries?
The large surface area of capillaries reduces blood flow pressure.
33
What does “closed circulatory system” mean?
Blood is contained within vessels and pumped around the body by the heart.
34
What is the role of the right atrium in the heart?
It receives deoxygenated blood from the body via the vena cava.
35
What is the role of the left atrium in the heart?
It receives oxygenated blood from the lungs via the pulmonary vein.
36
What type of blood does the pulmonary artery carry, and where does it take it?
Deoxygenated blood to the lungs.
37
What type of blood does the pulmonary vein carry, and where does it take it?
Oxygenated blood to the heart.
38
How does the heart ensure unidirectional blood flow?
By using valves that prevent backflow of blood
39
Why is the left ventricle wall thicker than the right ventricle wall?
It needs to pump blood at a higher pressure to the entire body.
40
What is the primary function of valves in the heart?
To prevent the backflow of blood
41
Which side of the heart contains oxygenated blood?
Left
42
Which side of the heart contains deoxygenated blood?
Right
43
What feature of arteries allows them to withstand high pressure?
Thick, muscular walls with elastic fibers.
44
Why do veins have thinner walls compared to arteries?
Because blood flows under lower pressure in veins
45
How do capillaries help exchange materials between blood and body cells?
Their thin walls and small size allow substances to diffuse easily.
46
Why is it important for capillaries to have a large surface area?
To maximize the exchange of gases and nutrients.
47
What happens to blood pressure as it moves from arteries to capillaries and veins?
Decreases
48
What structure ensures that blood moves efficiently through veins despite low pressure?
Pocket valves
49
Name the two circuits in a double circulatory system.
Pulmonary circuit and systemic circuit.
50
Why is the double circulatory system more efficient than a single circulatory system?
It maintains higher pressure, allowing faster oxygen and nutrient delivery.
51
In a closed circulatory system, what keeps blood separate from body tissues?
Blood vessels
52
What is the main difference between the pulmonary and systemic circuits?
The pulmonary circuit carries blood between the heart and lungs, while the systemic circuit carries blood between the heart and the rest of the body.
53
What does the P wave represent on an ECG?
Atrial contraction (atrial depolarization).
54
What does the QRS complex represent on an ECG?
Ventricular contraction (ventricular depolarization).
55
What does the T wave represent on an ECG?
Ventricular relaxation (ventricular repolarization).
56
What event occurs when the atrioventricular (AV) valves open?
Blood flows from the atria into the ventricles.
57
What causes the AV valves to close?
Ventricular contraction, which increases pressure in the ventricles.
58
What is the function of the semilunar valves?
They prevent backflow of blood from the arteries into the ventricles.
59
What causes the semilunar valves to open?
When ventricular pressure exceeds artery pressure.
60
Where does the sinoatrial node (SAN) send electrical impulses?
Across the atria to trigger their contraction.
61
What is the role of the atrioventricular node (AVN)?
To delay the electrical impulse before passing it to the ventricles.
62
What is the role of the Bundle of His?
It transmits electrical impulses down the septum of the heart.
63
What structure ensures coordinated contraction of the ventricles?
Purkyne fibers.
64
Why does oxygen dissociate more easily from hemoglobin at lower pH levels?
Because carbon dioxide forms carbonic acid, lowering blood pH and reducing hemoglobin’s affinity for oxygen (Bohr effect).
65
Why does oxygen dissociate more easily from hemoglobin at lower pH levels?
Because carbon dioxide forms carbonic acid, lowering blood pH and reducing hemoglobin’s affinity for oxygen (Bohr effect).
66
What is the Bohr effect?
The decrease in hemoglobin’s affinity for oxygen in the presence of high carbon dioxide concentration.
67
What adaptation of red blood cells maximizes oxygen transport?
Biconcave shape, which increases surface area.
68
How does fetal hemoglobin differ from adult hemoglobin?
Fetal hemoglobin has a higher affinity for oxygen to absorb oxygen from the mother’s blood.
69
What is shown by a leftward shift in the oxygen dissociation curve?
Increased oxygen affinity (e.g., fetal hemoglobin).
70
What does a rightward shift in the oxygen dissociation curve indicate?
Decreased oxygen affinity, promoting oxygen release to tissues (Bohr effect).
71
What happens to blood pressure as blood moves from arteries to capillaries?
It decreases due to resistance in the smaller vessels.
72
Why is the delay at the AV node important?
It allows the atria to finish contracting before the ventricles contract.
73
What structure initiates the heartbeat?
The sinoatrial node (SAN)
74
What happens during ventricular systole?
The ventricles contract, increasing pressure and forcing blood into the arteries.
75
What happens during diastole?
The heart relaxes, and blood fills the atria and ventricles.
76
What adaptation allows red blood cells to carry more oxygen?
Lack of a nucleus, which provides more space for hemoglobin.
77
Why does the oxygen dissociation curve have an S-shape?
Cooperative binding of oxygen to hemoglobin.
78
What happens when semilunar valves close?
Prevents backflow of blood into the ventricles during diastole.
79
What does “ventricular systole” refer to in the cardiac cycle?
The phase when the ventricles contract to pump blood into the arteries.
80
What is “atrial systole”?
The phase when the atria contract to push blood into the ventricles.
81
What does “diastole” mean in the cardiac cycle?
The relaxation phase when the heart chambers fill with blood.
82
Why do semilunar valves close after ventricular systole?
To prevent backflow of blood from the arteries into the ventricles.
83
What is the function of Purkyne fibers in the heart?
They distribute electrical impulses through the ventricles to cause coordinated contraction.
84
What happens to blood pressure in the arteries during ventricular systole?
It increases as blood is pumped out of the heart.
85
What would happen if the atrioventricular valves did not close properly?
Blood would flow back into the atria during ventricular contraction.
86
How does the sinoatrial node (SAN) act as the pacemaker of the heart?
It generates electrical impulses that initiate each heartbeat.
87
Why is the biconcave shape of red blood cells important?
It increases the surface area for efficient gas exchange.
88
What allows fetal hemoglobin to extract oxygen from maternal blood?
Fetal hemoglobin has a higher affinity for oxygen compared to adult hemoglobin.
89
How does cooperative binding affect hemoglobin’s oxygen dissociation curve?
It gives the curve its S-shape, as binding one oxygen molecule increases hemoglobin’s affinity for additional oxygen molecules
90
What environmental conditions cause a rightward shift of the oxygen dissociation curve?
High carbon dioxide concentration, low pH, and higher temperatures.
91
Why is the Bohr effect important during exercise?
It promotes the release of oxygen to actively respiring tissues that produce more carbon dioxide.
92
What structural adaptation of red blood cells increases their flexibility?
The absence of a nucleus and biconcave shape allow them to squeeze through capillaries.
93
What is measured by an electrocardiogram (ECG)?
The electrical activity of the heart during each cardiac cycle.
94
What does a flatline between the T wave and the next P wave on an ECG indicate?
The period of diastole when the heart is at rest and filling with blood.
95
What would a blockage in the Bundle of His affect?
The conduction of electrical impulses to the ventricles, disrupting coordinated contractions.
96
Why does the oxygen dissociation curve shift to the left for fetal hemoglobin?
To ensure the fetus can absorb oxygen from the mother’s blood even at lower oxygen levels.
97
What causes the “lub-dub” sounds of the heart?
The closing of the atrioventricular valves (“lub”) and semilunar valves (“dub”).
98
How does pH affect hemoglobin’s affinity for oxygen?
Lower pH (more acidic) decreases affinity, promoting oxygen release.
99
What is the significance of maintaining a pressure gradient in blood vessels?
It ensures continuous blood flow throughout the body.
100
Why do capillaries have very thin walls
To allow efficient diffusion of gases, nutrients, and waste products between blood and tissues.
101
What role do elastic fibers in arteries play?
They allow the arteries to stretch and recoil to maintain blood pressure.
102
How does the AV node help coordinate heart contractions?
It delays the impulse, allowing the atria to contract fully before the ventricles.
103
Why is it important for semilunar valves to remain closed during ventricular diastole?
To prevent backflow of blood from the arteries into the ventricles.
104
What does an oxygen dissociation curve (ODC) show?
The relationship between oxygen partial pressure and the percentage saturation of hemoglobin.
105
What does a leftward shift in the ODC indicate?
Higher hemoglobin affinity for oxygen, making it less likely to release oxygen to tissues.
106
What does a rightward shift in the ODC indicate?
Lower hemoglobin affinity for oxygen, promoting oxygen release to tissues.
107
What factors cause a rightward shift of the oxygen dissociation curve?
Increased CO₂, decreased pH (Bohr effect), and higher temperatures.
108
What factors cause a leftward shift of the oxygen dissociation curve?
Decreased CO₂, increased pH, and lower temperatures.
109
Why does fetal hemoglobin produce a curve shifted to the left compared to adult hemoglobin?
Fetal hemoglobin has a higher affinity for oxygen to absorb it efficiently from maternal blood.
110
How does the shape of the oxygen dissociation curve reflect cooperative binding
It has an S-shape (sigmoidal curve) because binding one oxygen molecule increases the affinity for others.
111
Why is a rightward shift in the oxygen dissociation curve beneficial during exercise?
It helps release more oxygen to muscles that are producing CO₂ and experiencing increased acidity.
112
What is the significance of the plateau phase of the oxygen dissociation curve?
It ensures hemoglobin remains highly saturated with oxygen even at slightly lower oxygen levels in the lungs.
113
What happens at Point A on the oxygen dissociation curve if it shows a lower percentage of saturation?
Oxygen is being released to actively respiring tissues where partial pressure of oxygen is lower.
114
How does the oxygen dissociation curve change at high altitudes?
It may shift slightly to the left, helping the body maintain oxygen uptake in low-oxygen environments.
115
Why does hemoglobin need to release oxygen more easily in tissues with higher CO₂ concentrations?
Because those tissues are metabolically active and require more oxygen for respiration.
116
What adaptation allows animals living in low-oxygen environments to have a left-shifted ODC?
Higher oxygen affinity to efficiently bind oxygen even at low partial pressures.
117
How does the ODC illustrate the importance of hemoglobin’s ability to load and unload oxygen efficiently?
The S-shape ensures full loading in the lungs and efficient unloading in tissues with lower oxygen concentrations.
118
What acid is formed when CO₂ enters a red blood cell?
Carbonic acid (H₂CO₃)
119
What enzyme catalyzes the formation of carbonic acid from CO₂ and water?
Carbonic anhydrase.
120
Into which ions does carbonic acid dissociate?
Hydrogen ions (H⁺) and bicarbonate ions (HCO₃⁻).
121
What ion enters red blood cells when bicarbonate ions leave to maintain charge balance?
Chloride ions (Cl⁻).
122
What is the role of hemoglobin in buffering blood pH?
It binds to hydrogen ions (H⁺) to maintain blood pH.
123
What effect does CO₂ have on hemoglobin’s oxygen affinity?
CO₂ lowers hemoglobin’s oxygen affinity, causing it to release oxygen more easily.
124
What is the name of the phenomenon where CO₂ reduces hemoglobin’s oxygen affinity?
The Bohr effect.
125
In what three ways is CO₂ transported in the blood?
Dissolved in plasma, as bicarbonate ions, and bound to hemoglobin.
126
Why does hydrostatic pressure drop as blood moves through a capillary?
Due to resistance and fluid loss
127
Which molecules are too large to leave the capillaries during tissue fluid formation?
Large proteins
128
Where is hydrostatic pressure highest: arteriole or venule end of a capillary?
Arteriole end.
129
Where is water potential highest: in blood plasma or tissue fluid?
Blood plasma
130
Where is water potential lowest: in blood plasma or tissue fluid?
Tissue fluid
131
Under what conditions does tissue fluid form: when HP > OP or HP < OP?
When HP > OP.
132
How is excess tissue fluid removed from the body?
Through the lymphatic system
133
How do glucose and oxygen concentrations compare between tissue fluid and blood plasma?
Both are lower in tissue fluid than in blood plasma.
134
How do CO₂ concentrations compare between tissue fluid and blood plasma?
CO₂ concentration is higher in tissue fluid than in blood plasma.
135
What type of vessels does lymph travel in?
Lymphatic vessels
136
What happens when there is a diet low in protein or a leaky capillary membrane?
Osmotic pressure is reduced, causing fluid to build up in tissues and leading to swelling (edema).
137
How does a low plasma protein concentration contribute to edema?
It reduces osmotic pressure, preventing water from being retained in the blood vessels
138
What happens when hydrogen ions (H⁺) are released in the blood?
They lower the pH, making the blood more acidic.
139
How does hemoglobin help maintain blood pH?
By accepting hydrogen ions to form hemoglobinic acid.
140
What happens to bicarbonate ions (HCO₃⁻) after they are formed in red blood cells?
They diffuse out into the plasma.
141
Why does chloride shift occur in red blood cells?
To maintain electrical neutrality when bicarbonate ions leave the cell.
142
What is the purpose of the Bohr effect in respiration?
It ensures more oxygen is released to active tissues with high CO₂ levels.
143
What are the consequences of high hydrostatic pressure at the arteriole end of a capillary?
Fluid is forced out of the blood, forming tissue fluid.
144
What role does osmotic pressure play at the venule end of a capillary?
It draws water back into the capillary due to plasma proteins.
145
What prevents all the fluid from being reabsorbed into the capillaries?
The balance between hydrostatic and osmotic pressures leaves some fluid in the tissue.
146
What happens to the tissue fluid that is not reabsorbed by the capillaries?
It is collected by the lymphatic system.
147
How does the lymphatic system return tissue fluid to the blood?
Through lymphatic vessels that drain into the circulatory system near the heart.
148
What causes the water potential difference between blood plasma and tissue fluid?
The presence of plasma proteins in blood plasma that are absent in tissue fluid.
149
Why is the glucose concentration lower in tissue fluid than in blood plasma?
Cells absorb glucose from the tissue fluid for respiration.
150
Why does tissue fluid have a higher concentration of CO₂ than blood plasma?
Because cells produce CO₂ as a waste product of respiration.
151
What is edema, and what causes it
Swelling caused by the accumulation of excess tissue fluid, often due to low plasma protein concentration or leaky capillaries.
152
How does a lack of plasma proteins reduce osmotic pressure?
Without enough proteins, less water is drawn back into capillaries, causing fluid accumulation in tissues.
153
What is the function of carbonic anhydrase in red blood cells?
It catalyzes the reaction between CO₂ and water to form carbonic acid.
154
What would happen if the hydrogen ions in the blood were not buffered by hemoglobin?
The blood pH would drop, leading to acidosis.
155
What is the role of nasal capillaries in conditioning inhaled air?
Nasal capillaries warm the inhaled air by transferring heat from the blood to the air, ensuring it reaches the lungs at an optimal temperature for gas exchange.
156
Why is it important for inhaled air to be warmed before reaching the lungs?
Warming inhaled air protects delicate lung tissues and ensures efficient gas exchange in the alveoli.
157
How does the structure of the nasal passages facilitate the warming of inhaled air?
The nasal passages contain a dense network of blood vessels close to the surface, allowing efficient heat transfer to the inhaled air.
158
What is the function of the coronary arteries?
To supply oxygenated blood and nutrients to the heart muscle and remove waste products
159
Where do the coronary arteries originate
They branch off from the aorta near the heart
160
Why do heart muscles need a blood supply from coronary arteries?
For aerobic respiration to produce ATP for continuous contraction.
161
What happens if a coronary artery becomes blocked?
No oxygen or nutrients transported to heart
No energy for heart muscles to contract It can cause angina or a heart attack (myocardial infarction).
162
What are the key features of an efficient gas exchange surface?
Large surface area
Thin, permeable surfaces
Moist surfaces
Steep concentration gradient
163
What is the function of the renal artery?
It carries oxygenated blood containing metabolic waste products from the aorta to the kidneys.
164
What does blood in the renal artery contain?
Oxygen, nutrients, and metabolic waste products like urea.
165
What is the role of the inferior vena cava?
It carries deoxygenated blood from the body, including the kidneys, back to the right atrium of the heart.
166
How does blood composition differ between the renal artery and vena cava?
Renal artery: Oxygen-rich, contains waste for filtration.
Vena cava: Deoxygenated, low in waste after filtration by kidneys.
