EX 2; The Heart Flashcards Preview

AU14 Physiology > EX 2; The Heart > Flashcards

Flashcards in EX 2; The Heart Deck (55):
1

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

hematocrit; should be roughly 45%

2

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

4.5-3 = 1.5L
1.5/4.5 = 33% hematocrit

3

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

capillaries

4

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

muscle
kidneys
abdominal organs

5

This is the volume per unit time

flow

6

What is the equation for determining flow

change in pressure/resistance

7

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

resistance

8

What can affect resistance

change in radius

9

What is the equation for resistance

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

10

This can alter the resistance and thereby flow

blood viscosity

11

What causes the heart valves to open and close

pressure differences

12

How does the electrical conduction flow through the heart

via gap junctions; allowing it to be very rapid

13

What is the flow of the electrical current through the heart

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

14

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

SA node

15

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

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

16

What is the P

atrial depolarization

17

What is the QRS

ventricle depolarization

18

What is the T

ventricle repolarization

19

What happens to the atrial repolarization

it is "lost" in the QRS series

20

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

voltage gated sodium channels

21

The prolonged "plateau" of depolarization is due to what

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

22

This results in the repolarization phase

opening of the potassium channels

23

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

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

24

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

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