Physiology- Cardio Flashcards
1
Q
What are the 3 main plasma proteins?
A
Albumin
Globulins
Fibrinogen
2
Q
What is the major blood electrolyte?
A
sodium
3
Q
Where does erythropoiesis occur?
A
bone marrow
4
Q
Cessation of bleeding is known as what?
A
hemostasis
5
Q
What is the role of platelets in hemostasis?
A
they stick to the injured site causing a platelet plug
6
Q
What do you call a clot that includes RBCs?
A
a thrombus
7
Q
What makes up a clot?
A
platelet plug plus fibrin
8
Q
Vitamin K is important for which clotting factors?
A
II, VII, IX, X
9
Q
What initiates the intrinsic pathway of the blood coagulation cascade?
A
blood coming into contact with exposed collagen of the damaged tissues.
10
Q
What mineral is needed for proper clotting?
A
calcium
11
Q
What is the insoluble substance that precipitates out at an injury site?
A
fibrin
12
Q
Hemophilia is a genetic absence of what clotting factors?
A
Hemophilia A: Factor VIII
Hemophilia B: Factor IX
13
Q
What substance dissolves clots?
A
Plasmin
14
Q
What substance cleaves fibrinogen into fibrin?
A
Thrombin
15
Q
Myocardial cells have more of this organelle due to its high oxidative capacity:
A
mitochondria
16
Q
What cellular feature allows the heart to contract as a syncytium?
A
gap junctions between the muscle cells
17
Q
How do T tubules differ between cardia and skeletal muscle?
A
Cardiac: T tubules contain extracellular fluid high in calcium
Skeletal: T- tubules contain extracellular fluid that is low in calcium
18
Q
What structure brings depolarization inside the cardiac muscle and helps regulate cytoplasmic calcium?
A
t tubules
19
Q
What prevents tetanic contraction in cardiac muscle?
A
the long cardiac action potential
20
Q
What aspect of the action potential prevents a second action potential from taking place?
A
long refractory period of plateau period
21
Q
What is the originator of the cardiac action potential?
A
the SA node
22
Q
What property allows the SA node to function as a primary pacemaker?
A
small cell size allows it to spontaneously depolarize
23
Q
What acts as a delay station for the action potential?
A
The AV node
24
Q
Why does the AV node delay the action potential?
A
to allow atrial muscle to depolarize before ventricular muscle, to allow for filling
25
What can act as a secondary pacemaker in pathological conditions?
the AV node
26
What allows for rapid conduction of the action potential?
Bundle of His
Bundle Branch fibers
Purkinjie fibers
Specialized tracts
27
What is the sequence of electrical impulse in the heart?
SA node--> specialized tracts--> AV node and atrial muscle--> Bundle of HIS--> bundle branches--> Purkinjie fibers--> ventricular muscle
28
What serves to depress the heart rate at rest by slowing down the SA node?
parasympathetic nervous system
29
How does the sympathetic nervous system affect conduction through the electrical system?
it speeds up conduction of the action potential and therefore increases heart rate
30
What nerve has the greatest influence on the heart?
the vagus nerve
31
What is the affect of vagal stimulation on the heart?
It serves to slow the conduction of action potentials through the AV node due to the parasympathetic nerve fibers
32
How does norepi affect heart contractility?
it increases heart contractility
33
In which phase do the ventricle fill?
late diastole
34
In which phase do we get isovolumetric contraction?
early systole
35
What phase of the cardiac cycle uses up the most energy?
the isovolumetric contraction of early systole
36
What is the purpose of isovolumetric contraction?
to build up the pressure so as to overcome the high aortic pressure
37
In which phase is ejection?
late systole
38
When is the relaxation phase?
early diastole
39
What causes heart sound 1?
closing of atrioventricular valves (mitral and tricuspid)
40
What causes heart sound 2?
closing of pulmonic and aortic valves
41
When in the cycle is S1?
late diastole/early systole
42
When in the cycle is S2?
end systole/ early diastole
43
What records electrical activity of the heart?
EKG
44
What information do we get from an EKG?
heart rate, rhythm, axis of the heart
45
What on an EKG marks atrial depolarization?
P wave
46
What on an EKG marks ventricular depolarization?
QRS complex
47
What on an EKG marks ventricular depolarization?
T wave
48
What 2 things influence cardiac output?
heart rate and stroke volume
49
How does the heart adapt to hypertension?
increases wall thickness--> cardiac hypertrophy
| cardiac dilation
50
What are the 3 major substrates for cardiac metabolism?
fatty acids, glucose, glycogen breakdown
51
What are 3 minor substrates for cardiac metabolism?
Lactic acid, ketones, intramuscular triglycerides
52
What is the major limitation of energy metabolism by myocardium?
coronary blood flow delivering oxygen
53
What 2 factors determine oxygen consumption by the myocardium?
1. wall tension in the heart that must be overcome e.g. during isovolumetric contraction
2. Isotonic contraction to eject the blood
54
What property of blood vessels helps push blood through the arteriole system?
elastic tissue
55
What property of blood vessels does smooth muscle provide?
its ability to contract and dilate allows blood to be shunted from one area to another
56
What protects blood vessels against distension?
the fibrous nature of the tissue
57
What type of circulation has few controls, and is a low pressure/low resistance system?
pulmonary circulation
58
What serves as a conduit for blood?
arteries
59
What types of blood vessels are resistance vessels due to their smooth muscle?
arteries and arterioles
60
What blood vessel in involved in nutrient and waste exchange?
capillaries
61
What type of capillary excludes proteins and cells from passing through?
Continuous capillaries
62
What type of capillary excludes cells? Where are they found?
fenestrated capillaries, found in the kidney
63
What type of capillary allows cells and protein to pass through? Where are they found?
sinusoidal/ discontinuous
| found in liver, bone marrow, spleen
64
What blood vessels act as capacitance vessels?
veins and venules
65
What increases venous return?
vasoconstriction
66
Which blood vessels have valves?
veins and venules
67
What are the 4 pressures that affect capillary exchange?
1. plasma oncotic pressure
2. plasma hydrostatic pressure
3. interstitial oncotic pressure
4. interstitial hydrostatic pressure
68
Which of the 4 capillary pressures favors filtration?
1. plasma hydrostatic pressure
| 2. Interstitial hydrostatic and oncotic pressure
69
Which of the 4 capillary pressures is actually a negative pressure or "suction"?
interstitial hydrostatic pressure
70
What are 3 mechanisms for edema?
1. increased plasma interstitial pressure
2. decreased plasma oncotic pressure
3. increased interstitial oncotic pressure
71
How will decreased blood protein synthesis cause edema?
by decreasing plasma oncotic pressure
72
What will influence lymph flow?
smooth muscle tone
| skeletal muscle contraction
73
Pressure in the right atrium or the vena cava at the level of the heart is known as what?
central venous pressure
74
What will increase venous blood flow and decreased venous pressure?
skeletal muscle contraction
75
Where are baroreceptors located?
aortic arch and carotids
76
What do baroreceptors sense?
blood pressure
77
What kind of neurotransmitters are released when baroreceptors are stimulated by high blood pressure?
inhibitory neurotransmitters
78
What do inhibitory neurotransmitters accomplish with relation to blood pressure?
decrease in sympathetic firing that innervate smooth muscle, causing vasodilation
79
What is accomplished by stimulation of baroreceptors?
decrease in blood pressure due to the vasodilation
80
Where are chemoreceptors located?
aortic arch and carotids
81
What are chemoreceptors sensitive to?
low blood oxygen levels as a result of decreased blood flow due to low blood pressure
82
What kind of neurotransmitter is released when chemoreceptors are stimulated by low blood pressure?
excitatory neurotransmitters
83
What to excitatory neurotransmitters do with relation to blood pressure?
increase sympathetic firing down neurons that innervate smooth muscle of blood vessels --> vasoconstriction
84
What is accomplished by the stimulation of chemoreceptors?
an increase in blood pressure by vasoconstriction
85
How does increased vagal output cause a decreased blood pressure?
via its parasympathetic effects that cause decreased heart rate --> decreased CO--> decreased BP
86
How does the kidney affect blood pressure?
via the renin angiotensin system: dec BP --> dec GFR--> renin released--> aldosterone release --> kidneys reabsorb Na and water--> increase in blood volume --> increased BP
87
How doe ADH affect blood pressure?
low BP --> ADH release--> kidney holds onto water--> increased blood volume --> inc BP
88
In metabolic control of blood flow, decreased oxygen causes release of metabolite (CO2, lactate etc.) which causes what?
vasodilation of blood vessels, metabolic acidosis
89
what is the name of the control that protects against high blood pressure damage?
autoregulation
90
What tissue is best at auto regulation?
the brain
91
What is the net result of blood vessels on auto regulation?
vasoconstriction
92
What is the long term control of blood flow called (ie. compensation for some type of tissue ischemia)
angiogenesis
93
What is the primary catecholamine for alpha adrenergic receptors?
norepinephrine
94
Which vascular beds have primarily alpha receptors?
skin, renal, splanchnic vasculature
95
What affect does Norepi have on smooth muscle cells in the vascular beds?
vasoconstriction
96
What is the primary catecholamine for beta 2 receptors?
epinephrine
97
Which vascular beds have primarily beta 2 receptors?
coronary and skeletal muscle vessels
98
What affect does epic have on smooth muscle in the vascular beds?
vasodilation
99
Which of the ANS branches has the most control over circulation?
sympathetics via norepi/epi
100
Which vascular beds are over perfused at rest?
skin, splanchnic and renal
101
Brain ischemia caused by and increase in CSF pressure is known as what?
Cushings reflex
102
When, during the cardiac cycle, are the coronary arteries perfused?
during diastole
