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MCAT BIOLOGY FLASHCARDS > MCAT BIO CH. 9 PART 1 > Flashcards

MCAT BIO CH. 9 PART 1 Flashcards

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1
Q

What is perfusion?

A

The flow of blood through a tissue

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2
Q

What is ischemic?

A

Inadequate blood flow resulting in tissue damage due to shortage of oxygen and nutrients and buildup of metabolic waste

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3
Q

What is hypoxia tissue?

A

Adequate circulation is present but the supply of oxygen is reduced

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4
Q

What is the difference between ischemia and hypoxia?

A

Waste build up in ischemia but removed in hypoxia

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5
Q

What is the difference between arteries and veins?

A

Arteries: Carry blood away from the heart at high pressure
Veins: Carry blood back toward the heart at low pressure

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6
Q

What do arteries branch into?

A

Arterioles; lower blood pressure

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7
Q

What do the arterioles lead to?

A

Capillaries

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8
Q

What important component do arterioles have in their walls and what does that allow?

A

Smooth muscle in their walls that can act as a control valve to restrict or increase the flow of blood into the capillaries of tissues

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9
Q

What important component do capillaries have in their walls and what does that allow?

A

Thin walls made of a single layer of cells; designed to allow the exchange of material between the blood and tissues

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10
Q

Where does blood go after it passes through capillaries?

A

Venules, small veins that lead into veins back to the heart

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11
Q

What do veins lack in their walls?

A

Lack a muscular wall

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12
Q

The inner lining of all blood vessels is formed by what?

A

A thin layer of endothelial cells

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13
Q

What are the four most important roles of endothelial cells?

A
  1. Vasodilation/constriction
  2. Inflammation
  3. Angiogenesis
  4. Thrombosis
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14
Q

What substances regulate vessel diameter?

A

Nitric oxide and endothelia

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15
Q

What is the important of vaso control?

A

Maintaining blood pressure, tissue oxygenation and thermoregulation

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16
Q

What does the release of inflammatory chemicals stimulate endothelial cells to do?

A

Increase there expression of adhesion molecules

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17
Q

What does the increase of adhesion molecules by endothelial cells allow?

A

Molecules allow white blood cells to adhere to the endothelial cells and enter the injured tissue

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18
Q

What is angiogenesis?

A

Formation of new blood vessels

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19
Q

What do angiogenesis growth factors stimulate?

A

Endothelial cells to break from an existing vessel and proliferate in surrounding tissues, creating new vessels

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20
Q

What does angiogenesis allow based on supply?

A

Increase supplies oxygen and nutrients to help sustain cell division and growth

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21
Q

What is thrombosis?

A

Blood clotting

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22
Q

How do endothelial cells prevent blood clots?

A

Secrete substances that inhibit the coagulation cascade

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23
Q

Which side of the heat has the pulmonary circulation? What about the systemic circulation?

A

Right side; left side

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24
Q

What is an exception to the rule of blood passing through only one set of capillaries before returning to the heart?

A

Portal systems

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25
Q

What happens in the hepatic portal system?

A

Blood goes through capillaries in intestine, collects in veins to travel to the liver, passes through capillaries again

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26
Q

What happens in the hypothalamic portal system?

A

Blood passes through capillaries in the hypothalamus to the portal veins then to the capillaries in the pituitary

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27
Q

Why do portal systems exist?

A

To transport nutrients or hormones without passing through the entire body

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28
Q

What happens in the atria?

A

Blood collects from the veins before getting pumped into the ventricles

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29
Q

What do the ventricles do?

A

Muscular ventricles pump blood out of the heart at high pressures into the arteries

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30
Q

The right atrium receives deoxygenated blood from which circulation and from which large veins?

A

The systemic circulation; inferior vena cava and superior vena cava

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31
Q

Where is the oxygenated blood from the lungs sent?

A

Return through the pulmonary veins to the left atrium and is pumped into the left ventricle

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32
Q

Which artery pumps the blood out of the left ventricle?

A

Aorta

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33
Q

What do the aorta branch into?

A

Coronary arteries

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34
Q

What do the coronary arteries do?

A

Branch to supply blood to the wall of the heart

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35
Q

Deoxygenated blood from the heart collects where?

A

Coronary veins

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36
Q

What do the coronary veins lead into?

A

Coronary sinus

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37
Q

Where is the coronary sinus located?

A

Beneath a layer of fat not he outer wall of the heart

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38
Q

What happens to the blood in the coronary sinus?

A

Drains directly into the right atrium

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39
Q

Why are valves necessary?

A

To ensure one-way flow through the circulatory system

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40
Q

What are the differences in pressures in the heart?

A

Ventricular pressure is very high and atrial pressure is low

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41
Q

What does the AV Valve stand for and what does it do?

A

Atrioventricular valve and its between each ventricle and its atrium; necessary to prevent backflow

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42
Q

Where are the bicuspid valve or mitral valve located?

A

Between the left atrium and the left ventricle

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43
Q

What would happen if the mitral valve ruptured?

A

Ventricle would pump blood in both directions, out the aorta and back into the left atrium

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44
Q

Where are the tricuspid valve?

A

AV Valve between the right atrium and right ventricle

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45
Q

What are the valve between the large arteries and the ventricles?

A

The pulmonary and aortic semilunar valves

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46
Q

Why are valves important throughout the venous system?

A

Necessary because in passing through capillaries, blood loses its pressure

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47
Q

What happens when the venous valves fail?

A

Varicose veins

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48
Q

What happens to the ventricles and atria during diastole?

A

Ventricles relax to allow blood in; atria contract to propel blood into the ventricles

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49
Q

What happens to the ventricles and atria during systole?

A

The ventricles contract

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50
Q

What happens during the initial contraction of systole to the valves?

A

The buildup pressure causes the AV valves to shut

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51
Q

What happens to the ventricles while the AV valve shut?

A

The pressure in the ventricles increase rapidly until the semilunar valves fly open

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52
Q

What happens when the semilunar valves fly open?

A

Blood rushes into the aorta and pulmonary artery

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53
Q

What is ejection fraction?

A

End of systole, the ventricles are nearly empty

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54
Q

What sound does the systole cycle make?

A

Ventricles contract; starts with the lub sound ending at the dup

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55
Q

What happens when the ventricles stop contracting at the end of systole?

A

Blood begins to flow backwards from pulmonary artery into the right ventricle and from aorta into the left ventricle

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56
Q

Even though back flow enters the ventricle, how much and why?

A

Very little back flow occurs because semilunar valves slam shut when the pressure in the ventricles becomes lower than the pressure in the great arteries

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57
Q

What causes the lub sound?

A

The lub sound results from the closure of the AV valves at the beginning of systole

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58
Q

What causes the dup sound?

A

The dup sound results from the semilunar valves closing at the end of systole

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59
Q

What is the heart rate/pulse?

A

The number of time the “Lub-dup” cardiac cycle is repeated per minute

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60
Q

What is the normal pulse rate (HR)?

A

One beat per second ranging from 45 beats per minute in athletes to 80 or more in elderly and children

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61
Q

What is the stroke volume (SV)?

A

The amount of blood pumped with each systole

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62
Q

What is the cardiac output (CO)?

A

The total amount of blood pumped per minute

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63
Q

What is the equation of cardiac output (CO)?

A

CO = SV X HR

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64
Q

What is the Frank-Starling mechanisms?

A

The heart muscled will contract more forcefully if its stretched

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65
Q

How does the heart muscle get more stretched out to increase contract?

A

Increasing venous return

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66
Q

How can the body increase venous return?

A
  1. Increase blood volume

2. Contract on of large veins

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67
Q

How can the body increase venous return through increasing blood volume?

A

Retaining water and urinating less

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68
Q

From what is the force of contraction in the ventricles and the atria generated by?

A

The cardiac muscle cells that form the muscular walls the chambers of the heart

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69
Q

What do muscles cells have that allow them to contract?

A

Share with neurons the ability to propagate an action potential across their surface

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70
Q

Do ligand-gated ion channels propagate action potentials in cardiac muscle?

A

No, propagation of action potentials requires voltage-gated ion channels

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71
Q

What is a syncytium?

A

A tissue in which the cytoplasm difference cells can communicate via gap junctions

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72
Q

Where are the gap junctions found in cardiac muscles?

A

There intercalated disks

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73
Q

How is the action potential in the heart transmitted from the atrial syncytium to the ventricles?

A

Cardiac conduction system

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74
Q

What allows the atria to contract first before the ventricles?

A

Transmission of the action potential is delayed slightly as it passes through the A-V node

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75
Q

What two channels are important in cardiac muscle action potential?

A
  1. Fast sodium channels

2. Slow calcium channels

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76
Q

What is the effect of the slow calcium channel in the cardiac muscle?

A

Stay open longer; causes membrane depolarization to last longer in cardiac muscle than neurons, producing plateau phase

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77
Q

What do cardiac muscles have to maximize the entry of calcium in the cell?

A

T-tubules

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78
Q

What is the purpose of T-tubules in cardiac muscles?

A

Action potentials travel down along it and allow the entry of calcium from extracellular environment and induced sarcoplasmic reticulum to release some Ca2+

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79
Q

What does the combination of intracellular and extracellular calcium causes in cardiac muscles?

A

Contraction of actin-myosin fibers

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80
Q

What is the initiation of each action potential that asters each cardiac cycle that its is occur automatically?

A

Sinoatrial node (SA) in the right atrium

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81
Q

Under normal circumstances, the SA nodes cells act as what?

A

Pacemaker of the heart

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82
Q

What are the three phases of the SA node?

A

Phase 0, Phase 3 and Phase 4

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83
Q

The SA node is unique that it is an u…?

A

Unstable resting potential

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84
Q

What is Phase 4 of the SA node?

A

Automatic slow depolarization caused by special sodium leak channels that are responsible for rhythmic, automatic excitation

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85
Q

What does Phase 4 from the sodium leak channels allow based on the SA node?

A

Inward sodium leak brings cell potential to the threshold for voltage-gated calcium channels

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86
Q

What does the opening of the voltage-gated calcium channels occur in Phase 4, what does it case based on SA node?

A

Phase 0, the upstroke of the pacemaker potential

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87
Q

What is the upstroke of the pacemaker potential in Phase 0 caused by?

A

Caused by an inward flow of Ca 2+

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88
Q

Skeletal muscle cells and other myocytes depolarize because due to what instead of the inward flow of Ca 2+?

A

Because of a Na+ influx

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89
Q

What does the influx of Ca 2+ in Phase 0 of the SA node cause?

A

Drives the membrane potential of the SA nodal cells towards the positive Ca 2+

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90
Q

How are the CA 2+ channels compared to the Na + channels based on SA node Phase 0?

A

Phase 0 Ca 2+ channels open more slowly, leading to a more gradual upsweep in the action potential

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91
Q

What is Phase 3 of the SA node phases?

A

Repolarization

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92
Q

What happens during Phase 3 of the SA node?

A

Closure of the Ca 2+ channels and opening of the K+ channels

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93
Q

What does the opening of the K+ channels cause during the Phase 3 Sa node?

A

Drives the membrane potential back down towards the negative K+ equilibrium potential

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94
Q

Based on the phases, summarize what the SA node does based on action potential?

A

Transmits action potential through intercalated discs, repolarize and starts process again

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95
Q

What regions of the earth can spontaneously depolarize?

A

the Av node, Purkinje fibers, SA node

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96
Q

Why is the SA node called the pacemaker of the heart?

A

It has more NA+ leak channels, reaching threshold before any other region of the heart does

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97
Q

What is the resting potential of the cardiac muscle cells?

A

Resting membrane potential of about -90 mV and a long duration of 300 mms

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98
Q

What is the resting membrane potential of the SA node?

A

-50 and self-depolarizes right away

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99
Q

What are the phases of cardiac muscle cells?

A

Phase 0-4

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100
Q

What is the name of the phase 0 of cardiac muscle cells?

A

Depolarization

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101
Q

What happens during phase 0 of cardiac muscle cells?

A

Upstroke of the action potential; caused by transient increase in Na+ conductance

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102
Q

What happens when there an upstroke of the action potential in one of the intercalated disks, based on Phase 0?

A

Intercalated disks stimulate myocytes to reach threshold for voltage-gated Na+ channels

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103
Q

What happens when threshold is reached in Phase 0 of the cardiac muscle cell?

A

Na+ channels open and Na+ rushes into the cell

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104
Q

What is the name of the phase 1 of cardiac muscle cells?

A

Initial depolarization

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105
Q

What happens during phase 1 of cardiac muscle cells?

A

The Na+ channels inactivate and K+ channels open

106
Q

What does the opening of K+ channels cause in phase 1 of cardiac muscle cells?

A

Efflux of K+ and a slight drop in cell potential

107
Q

What in phase 1 leads into phase 2 of the cardiac muscle cells?

A

Increase potential due to initial Na+ influx causing the Ca 2+ channels to open

108
Q

What is the name of the phase 2 of cardiac muscle cells?

A

Plateau phase

109
Q

What happens during phase 2 of cardiac muscle cells?

A

The influx of Ca2+ ions balance the K+ efflux from phase 1, leading to an equilibrium in cell potential

110
Q

What is the name of the phase 3 of cardiac muscle cells?

A

Repolarization

111
Q

What happens during phase 3 of cardiac muscle cells?

A

The Ca2+ channels close and the K+ channels stay open

112
Q

What happens during phase 4 of cardiac muscle cells?

A

Inward and outward current equal, dictated also by action of Na+/K+ ATPase and slow K+ leak channels

113
Q

What is the name of the phase 3 of cardiac muscle cells?

A

The resting membrane potential

114
Q

What is the internodal tract?

A

Pathway connecting the SA node to the AV node

115
Q

Why does the AV node spreads through the atria more slowly when there’s conductance?

A

Contracting heart muscle cells pass the impulse more slowly than specialized conduction fibers

116
Q

Where does the impulse go after it is slightly delayed through the AV node?

A

Tot he ventricles via the conduction pathway known as the AV bundle of bundle of His

117
Q

What does the AV bundle divide in and what is it called?

A

Left and right bundle branches and then into the Purkinje fibers

118
Q

The Purkinje fibers spread across the…..of the heart?

A

Inferior portion the ventricles, apex of the heart.

119
Q

The autonomic nervous system regulates the action potentials in the heart. T/F

A

False: Regulates the rate of contraction

120
Q

Why is the heart rate only 60-80 beats per minute?

A

Parasympathetic nervous system continually inhibits depolarization of the SA node

121
Q

What part of the parasympathetic nervous system inhibits depolarization of the SA node?

A

The vagus nerve contains preganglionic axons which synapse in ganglia near the SA node

122
Q

What do the preganglionic axons cause to the SA node?

A

Postganglionic neurons innervate the SA node and release acetylcholine (ACh)

123
Q

What does the acetylcholine in the SA node do, based on the vagus nerve?

A

Inhibits depolarization by binding to receptors on the cells of the SA node

124
Q

What is the vagal tone?

A

The constant level of inhibition caused by the vagus nerve

125
Q

The role of the parasympathetic system in controlling the heart is to modulate the rate by….?

A

Inhibiting rapid automaticity

126
Q

When does the sympathetic nervous system affect the heart?

A

When increased cardiac output is needed during a flight or fight response

127
Q

What are the two neurotransmitters related to the effect of the sympathetic nervous system onto the heart and how are the released?

A
  1. Norepinephrine released by postganglionic neurons

2. Epinephrine secreted by the adrenal medulla binds to receptor on cardiac muscle cells

128
Q

What is the effect of sympathetic activation?

A

Stimulatory and increases the heart rate

129
Q

What are the three components required in regulatory system?

A
  1. Input
  2. Integration
  3. Output
130
Q

What is another term for the input in regulatory system?

A

Afferent informaton

131
Q

What is another term for the output in regulatory system?

A

Efferent information

132
Q

What is another term for the integration in regulatory system?

A

Function of the central nervous system

133
Q

What is the key element in the regulation input of the heart rate?

A

Baroreceptors

134
Q

What do baroreceptors monitor?

A

Blood pressure

135
Q

Based on input, what happens when the baroreceptors send information the pressure is too high?

A

CNS increase vagal tone and decreases sympathetic input

136
Q

What is hemodynamic?

A

Study of blood flow

137
Q

What is the equation for Ohm’s Law?

A

Δ P = Q X R

138
Q

In the Ohm’s Law equation, what does delta P stand for?

A

Pressure gradient in mmHg

139
Q

In the Ohm’s Law equation, what does Q stand for?

A

Blood flow (or cardiac output in L/min)

140
Q

In the Ohm’s Law equation, what does delta R stand for?

A

Denotes resistance

141
Q

Based on blood flow, what is the resistance?

A

Opposing force of flow, friction

142
Q

Pressure is directly proportional to…?

A

Cardiac output and peripheral resistance

143
Q

If we want to change blood pressure, what are the only ways we can?

A

Changing pressure or the resistance

144
Q

What are the two ways pressure can vary, based on heart?

A

By changing the force (stroke volume) or rate (beats per minute)

145
Q

What is the precapillary sphincters?

A

Arteriolar smooth muscle

146
Q

What is the principal determinant of resistance in blood pressure?

A

Degree of constriction of precapillary sphincters

147
Q

The result of R = ΔP/Q, what does it give?

A

Peripheral resistance

148
Q

What controls the peripheral resistance?

A

The sympathetic nervous system controls the peripheral resistance

149
Q

A basal level of pressure is provided by what?

A

A constant level of norepinephrine released by sympathetic postganglionic axons innervating precapillary sphincters

150
Q

The constant nervous input from the sympathetic nervous system allowing for a basal level of pressure is called what?

A

Adrenergic tone

151
Q

When physician measure blood pressuring, they are actually measuring what?

A

Systemic arterial pressure

152
Q

What is the systemic arterial pressure?

A

Force per unit area exerted by blood upon the walls of arteries

153
Q

What are the two numbers from a blood pressure reading, such as 120/80?

A

120 mm Hg is the systolic pressure and 80 mm Hg is the diastolic pressure

154
Q

What is the pulse pressure?

A

The difference between systolic and diastolic pressures

155
Q

What is the blood pressure measured by?

A

Taken using a sphygmomanometer

156
Q

What is the pressure in the vena cava?

A

Blood pressure is negligible and valves must prevent back flow

157
Q

Why is there high diastolic aterial pressure as high as it is?

A

When the heart contracts, the arteries distend like balloons and during diastole, they exert pressure on the blood

158
Q

What is local autoregulation?

A

When a tissue is under-refused, wastes build up and vasodilation occurs automatically

159
Q

What are the three components of blood?

A

Plasma, leukocytes, hematocrit

160
Q

What are the three key components of plasma?

A
  1. Electrolytes
  2. Buffers
  3. Lipoproteins
161
Q

What are electrolytes?

A

Na+ K+ Cl- Ca2+ and Mg 2+ ions

162
Q

What do buffers achieve in the blood?

A

Maintain constant pH of 7.4

163
Q

What is the principal blood buffer?

A

Bicarbonate HCO3-

164
Q

What is the principal sugar in the blood?

A

Glucose

165
Q

What are the blood proteins?

A

Albumin, Immunoglobin, Fibrinogen, Lipoproteins

166
Q

What is albumin, based on protein?

A

Essential for maintenance of oncotic pressure

167
Q

What is oncotic pressure?

A

Osmotic pressure in the capillaries due to only plasma proteins

168
Q

What is the purpose of immunoglobulins?

A

Key part of the immure system

169
Q

What is fibrinogen important for?

A

Blood clotting

170
Q

What are lipoproteins?

A

Large particles consisting of fats, cholesterol and carrier proteins

171
Q

What is the role of lipoproteins?

A

Transports lipids in the bloodstreams

172
Q

What is the principal metabolic waste product?

A

Urea

173
Q

What is Urea?

A

A breakdown product of amino acid, carrier of excess nitrogen

174
Q

What is bilirubin?

A

A breakdown product of heme (oxygen-binding moiety of hemoglobin)

175
Q

What is the hemacrotit of blood?

A

Volume occupied by erythrocytes

176
Q

All the formed elements of the blood develop from special cells called what?

A

Bone marrow stem cells

177
Q

What is serum?

A

Liquid left when the blood clots; plasma that lacks proteins

178
Q

What hormone stimulates RBC production and where?

A

Erythropoeitin and in the bone marrow

179
Q

What happens aged RBCs?

A

Eaten by phagocytes in the spleen and liver

180
Q

What are features of erythrocytes?

A

Cell with no nucleus or other organelles such as mitochondria

181
Q

How long do RBCs live for?

A

120 day

182
Q

What do RBC rely on since they do not have mitochodria?

A

Rely on glycolysis for ATP synthesis

183
Q

What is the purpose of RBC?

A

Transport oxygen from lungs to the tissues and CO2 from the tissues to the lungs

184
Q

What from the RBC allows for a surface area large enough for gas exchange?

A

Flat, biconcave shape

185
Q

Why is the RBC able to carry oxygen?

A

Contains millions of molecules of hemoglobin

186
Q

What are the two most important blood group antigens?

A

ABO blood group and the Rh blood group

187
Q

What is the Rh blood group classification?

A

RR, Rr and rr

188
Q

What genotypes of Rh positive and which are Rh negative?

A

+: RR and Rr

-: rr

189
Q

What is a transfusion reaction?

A

Blood transfusions with the wrong antigen

190
Q

What is sensitization based on blood transfusion?

A

A person with Rh- blood for example is exposed to Rh+ blood and produces antibodies

191
Q

What is hemolytic disease of the newborn?

A

When the mother produces antibodies against a different blood and now her antibodies can cross placental barrier and destroy the baby’s RBC

192
Q

Why are AB+ and O- special blood types?

A

They do not make antibodies to any of the blood group antigens; universal recipients

193
Q

Why are AB+ know as universal recipients?

A

They can receive any of the other blood types without complication

194
Q

Why are O- know as universal donors?

A

Can donate blood to any of the other blood types without complication

195
Q

What are two ways a white blood cell move around?

A
  1. Amoeboid motility (Crawling)

2. Chemotaxis

196
Q

Why is white blood cells moving in crawling motion important?

A

Squeeze out of capillary intercellular junctions and can roam free in the tissues

197
Q

What is chemotaxis based on leukocytes movement?

A

Movement directed by chemical stimuli

198
Q

What can be the chemical stimuli to move leukocytes?

A

Toxins and waste products released by pathogens or chemical signals released by other white blood cells

199
Q

What are the six types of white blood cells?

A
  1. Monocytes
  2. Macrophages
  3. Lymphocytes
  4. B and T cell
  5. Granulocytes
  6. The -phils
200
Q

What are the three types of the -phil leukocytes?

A

Neutrophil, eosinophil and basophil

201
Q

What is the purpose of macrophages?

A

Phagocytose debris and microorganisms, amoeboid motility and chemotaxis

202
Q

What is the purpose of B cell?

A

Mature into plasma cell and produce antibodies

203
Q

What is the purpose of T cell?

A

Kill virus-infected cells, tumor cells and reject tissue grafts, also control immune response

204
Q

What is the purpose of neutrophil?

A

Phagocytose bacteria reusing in pus; amoeboid motility and chemotaxis

205
Q

What is the purpose of eosinophil?

A

Destroy parasites, allergic reactions

206
Q

What is the purpose of basophil?

A

Store and release histamine; allergic reactions

207
Q

What are platelets derived from?

A

Large bone marrow cells called megakaryotypes

208
Q

What is the purpose of the platelets?

A

Aggregate at the site of damage to the blood vessel wall and form a platelet plug

209
Q

What is hemostasis?

A

Preventing bleeding

210
Q

What is the hemostatic response of fibrin?

A

Fibrin mesh becomes a scab and seals and protects the wound

211
Q

What is the structure of the fibrin?

A

Threadlike protein which forms a mesh that holds the platelet plug together

212
Q

What is converted into fibrin and with the help of what?

A

Fibrinogen plasma protein is converted into fibrin by throbbing

213
Q

What is thrombus?

A

A blood clot; scar circulating the blood stream

214
Q

What is hemophilia?

A

Excessive bleeding

215
Q

What does each hemoglobin contain?

A

Heme, a large multi-ring structure that has a single iron atom bound at its center

216
Q

What is the role of heme with its iron atom?

A

Bind to O2

217
Q

What happens when none of the subunits have oxygen bound?

A

All four subunits of hemoglobin assume a tense conformation; low affinity for oxygen

218
Q

What happens to hemoglobin the one oxygen binds?

A

Conformation changes to a relaxed state that has higher affinity to oxygen

219
Q

What factors caused the hemoglobin to have ten conformation, which has a low O2 affinity?

A
  1. Decreased pH
  2. Increased PCO2 (level of Co2 in the blood)
  3. Increased tempoerature
220
Q

What is the Bohr effect?

A

Certain factors stabilize tense hemoglobin and thus reduce its oxygen affinity

221
Q

Why does the hemoglobin get a tense conformation in decreased pH?

A

Active tissue leads to more metabolizing glucose, elevated PCo2, cells run low on oxygen, performing lactic acid which dropsH

222
Q

Why does the hemoglobin get a tense conformation when temperature increases?

A

Temperature increases when there is a lot of metabolic activity

223
Q

How is most of the Co2 transport accomplished?

A

Conversion of CO2 to carbonic acid

224
Q

What can carbonic acid dissociate into?

A

Bicarbonate and a proton

225
Q

What is the advantage of bicarbonate and a proton being the dissociative components of carbonic acid?

A

Compound are extremely water-soluble and easily carried in the blood

226
Q

The conversion of CO2 into carbonic acid is catalyzed by an RBC enzyme called…?

A

Carbonic anhydrase

227
Q

How is 20% of CO2 is transported in the blood?

A

Being stuck Ono hemoglobin

228
Q

Why is binding of CO2 to hemoglobin important for hemoglobin?

A

Based on the Bohr effect, it further stabilizes tense Hb

229
Q

What is the least percentage of the way Co2 is transported in the blood and how?

A

7% - Dissolved in the blood and carried from the tissues to the lungs since its water soluble

230
Q

What are intercellular clefts of capillary walls?

A

Spaces between endothelial cells that make up the capillary walls

231
Q

What are the three substances that must be able to pass through the intercelluar clefts?

A

Nutrients, wastes, and white blood cells

232
Q

Is it necessary for O2and CO2 to pass through the clefts?

A

No, they can pass through by simple diffusion

233
Q

What are the main three types of nutrients?

A

Amino acids, glucose and lipids

234
Q

What is the purpose of the hepatic portal vein based on exchange of substances across the capillary wall?

A

Amino acids and glucose are absorbed from the digestive tract and carried through the special vein to the liver

235
Q

Why the hepatic portal vein called a portal vein?

A

Connects two capillary beds; the one in the intestinal wall and the one inside the liver

236
Q

What happens to the amino acid and glucose when they’re released into the blood streamy the liver?

A

They can pass through capillary clefts into the tissues

237
Q

What happens after fats are absorbed from the intestine?

A

Packaged into chylomicrons

238
Q

What do the chylomicrons do?

A

Enter tiny lymphatic vessels in the intestinal wall called lacteals

239
Q

What is lipemia?

A

A person’s blood appearing milky, lips flowing in the blood

240
Q

What happens when lacteals have been filled by chylomicrons?

A

Empty into large lymphatics which eventually drain into a large vein near the neck

241
Q

Where do lipoproteins carry fats for storage?

A

Adipocytes - fat cells

242
Q

What happens to waste produced during cellular metabolism?

A
  1. Diffuse through the capillary walls into the bloodstream
  2. Liver passes it into gut as bile
  3. Excreted by kidney
243
Q

What are the types of white blood cells that can squeeze through the clef of capillaries?

A
  1. Macrophages

2. Neutrophils

244
Q

Why are the two reasons as to why water has a great tendency to flow out of capillaries?

A
  1. Hydrostatic pressure created by the heart

2. High osmolarity of tissues drawing out water of the bloodstream

245
Q

How is the plasma osmolarity created?

A

Plasma osmolarity is provided by high concentrations of large plasma proteins, mainly albumin

246
Q

Why can albumin be used to create plasma osmolarity?

A

Its too large and rigid to pass through the clefts so it remains in the capillaries and keeps water there too

247
Q

What is oncotic pressure?

A

Osmotic pressure provided by plasma proteins

248
Q

How are the capillaries in general?

A

Hydrostatic pressure is high; water squeezes out into the tissues

249
Q

What happens to the capillaries when water continues to leave the capillary?

A

Concentration of plasma proteins increases

250
Q

What happens when the hydrostatic pressure is low in capillaries?

A

Blood very concentrated so oncotic pressure is high; water flows back into the capillary from the tissues

251
Q

Why is more water lost during inflammation?

A

Capillaries dilate, increasing the size of the intercellular clefs to let the white blood cells migrate into the tissues

252
Q

What is the result of inflammation since the capillaries dilate?

A

Edema; swelling as a result of water in the tissues

253
Q

What does the lymphatic duct have in their walls?

A

Smooths muscles in their walls

254
Q

What is the behavior of the lymphatic system; how does it act?

A

Acts like a suction pump to retrieve water, proteins and white blood

255
Q

What is the lymph?

A

The fluid inside the lymphatic vessels

256
Q

What do lymph nodes do?

A

Filters the lymph

257
Q

Why is the lymph nodes an important part of the immune system?

A

They contain white blood cells that can initiate an immune response against anything foreign

258
Q

What is the largest lymphatic vessel and where is it located?

A

The thoracic duct; located in the chest

259
Q

What does the thoracic duct dump into?

A

A large vein located in the neck

260
Q

Where does the lymphatic vessels dump dietary fats from the intestines into?

A

Dump dietary fats in the form of chylomicrons into the thoracic duct

MCAT BIOLOGY FLASHCARDS (23 decks)

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