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AU14 Physiology > EX 2; The Heart > Flashcards

EX 2; The Heart Flashcards

1
Q

This is a rapid assessment of blood composition; the percent of the blood volume that is composed of RBCs

A

hematocrit; should be roughly 45%

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2
Q

Estimate the hematocrit of a person with a plasma volume of 3L and a total blood volume of 4.5L

A
  1. 5-3 = 1.5L

1. 5/4.5 = 33% hematocrit

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3
Q

The exchange of oxygen, carbon dioxide, nutrients, and metabolic end products occurs at the level of what

A

capillaries

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4
Q

Which portions of the body receive the most blood flow at rest

A

muscle
kidneys
abdominal organs

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5
Q

This is the volume per unit time

A

flow

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6
Q

What is the equation for determining flow

A

change in pressure/resistance

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7
Q

This is how difficult it is for blood to flow between 2 points

A

resistance

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8
Q

What can affect resistance

A

change in radius

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9
Q

What is the equation for resistance

A

8(length)(fluid viscosity(ή))
divided by
Ħ (radius)^4

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10
Q

This can alter the resistance and thereby flow

A

blood viscosity

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11
Q

What causes the heart valves to open and close

A

pressure differences

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12
Q

How does the electrical conduction flow through the heart

A

via gap junctions; allowing it to be very rapid

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13
Q

What is the flow of the electrical current through the heart

A

SA - atria - AV - bundle of His - bundle fibers - ventricles

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14
Q

This is the hearts pacemaker because it initiates each wave of excitation with atrial contraction

A

SA node

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15
Q

What is the role of the bundle of His and other parts of the conduction system

A

deliver the excitation to the apex of the heart so that ventricular contraction occurs in an upward sweep

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16
Q

What is the P

A

atrial depolarization

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17
Q

What is the QRS

A

ventricle depolarization

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18
Q

What is the T

A

ventricle repolarization

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19
Q

What happens to the atrial repolarization

A

it is “lost” in the QRS series

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20
Q

The rapid opening of what is responsible for the rapid depolarization phase

A

voltage gated sodium channels

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21
Q

The prolonged “plateau” of depolarization is due to what

A

the slow but prolonged opening of voltage gated calcium channels plus the closures of the potassium channels

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22
Q

This results in the repolarization phase

A

opening of the potassium channels

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23
Q

These two things cause a threshold graded depolarization in the action potential of an auto rhythmic cardiac cell

A

sodium ions “leaking” in through the F-type (funny) channels plus Ca ions moving through the T channels

24
Q

in the action potential of an auto rhythmic cardiac cell, the rapid opening of this is responsible for the rapid depolarization phase

A

voltage gated calcium channels

25
in the action potential of an auto rhythmic cardiac cell, these two things are responsible for the repolarization plhase
reopening of the potassium channels | closing of the calcium channels
26
A myocyte cannot beat outside of the heart, why
because it needs the SA node to be active
27
A SA nodal cell will beat outside of the heart, why
due to the automaticity of the funny channel; it does not have a resting membrane potential
28
How does the electrical signal transfer to a contractile force
excitation-contraction coupling
29
Excitation-contraction coupling links the cardiac muscle cell action potentials to contraction via what
control of calcium within the myocardium | calcium induced calcium release
30
The prolonged refractory period of cardiac muscle prevents what two things
tetanus | and allows time for the ventricles to fill with blood prior to pumping
31
Cardic activity can be expressed as what
cardiac output; in reference to the amount of blood moved per unit of time
32
What is the first heart sound
closure of the AV valves
33
What is the second heart sound
closure of the aortic and pulmonary valves
34
What are three defects of the heart causing murmurs
stenosis = narrowing regurgitation = insufficiency septal defects
35
Which portion of the blood flow is in a series; where the components are connected end-to-end
pulmonary circuit
36
Which portion of the blood flow is in parallel; where components are connected between the same two sets of electrically common points, creating multiple paths
systemic circulation
37
What does the parallel blood flow of the systemic system allow for
organs to get 100% of oxygenated blood
38
This is the volume of blood each ventricle pumps per minute or the volume of blood flowing through either the pulmonary or systemic circuit per minute
cardiac output
39
What is the equation for cardiac output
CO = HR x SV
40
The parasympathetic system acts upon which receptors on the heart
muscarinic
41
Does the parasympathetic act on the atria or ventricles
atria | muscarininc receptors on the atria
42
What neurotransmitter does the PS release
ACh
43
The sympathetic system acts upon which receptors on the heat
beta
44
Does the sympathetic act on the atria or ventricles
both!
45
What neurotransmitters does the S system release
NE and E
46
What two things can be used to speed up heart rate
increase sympathetic control; NE and E | decrease parasympathetics control; reduce ACh
47
What are the three factors influencing stroke volume
pre-load; the volume of blood in the ventricles just before contraction (end-daistolic volume) magnitude of sympathetic input to the ventricles afterload; the pressure against which the ventricles pump
48
What is the Frank-Starling mechanism
increasing the stroke volume
49
In which two ways can you increase the stroke volume via Frank-Starling Mechanism
fill it more with blood | deliver sympathetic signals
50
What does sympathetic signals do to the contractile force
they cause a stronger and more rapid contraction and more rapid relaxation
51
Sympathetic effects cause an increase in this, which increases contraction
calcium
52
True or False | It is possible to affect stroke volume without affecting heart rate
False; it is not possible, under normal circumstances, to increase SV or HR without influencing the other
53
What are five ways in which to measure cardiac function
``` thermodultion cardiac output angiography echocardiogram MRI ejection franction ```
54
This occurs is 1:500 people, characterized by increased heart all thickening particularly in the inter ventricular septum interfering with blood ejection
hypertropic cardiomypathy
55
What are three symptoms of hypertrophic cardiacmyopathy
angina arrhythmyas sudden cardiac death

AU14 Physiology (24 decks)

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