Cardiovascular Physiology Flashcards Preview

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Flashcards in Cardiovascular Physiology Deck (55):
0

How many liters of blood per minute is pumped in a 70kg man

5-6 liters

1

What is ANP (atrial natriuretic peptide) released in response to?

Increased atrial pressure

2

What is BNP (b-type natriuretic peptide) released in response to?

overstretched ventricles

3

Intercalated discs allow the heart to contract in synchrony as one unit, what is this called?

Syncytium

4

What is happening with the ions in the initial repolarization in cardiac muscle contraction?

Inactivation of Na+ influx
K+ efflux

5

What is happening in the plateau phase of the cardiac muscle contraction? (ions)

Ca++ influx through L-type Ca++ channels

6

What determines the force of contraction of the myocardial cell?

The amount of intracellular calcium

7

No action potential can be initiated regardless of the stimulus strength, what refractory period is this?

Absolute refractory period

8

An action potential can be elicited, however a greater stimulus is needed, what refractory period is this?

Relative refractory period

9

Why is cardiac muscle incapable of sustained contraction (tetany) as in skeletal muscle?

Because of the relatively long refractory period

10

What is the Frank-Sterling law?

Cardiac output is directly proportional to venous return

11

The 1st heart sound is due to what?

Closure of the tricuspid and mitral valves

12

The 2nd heart sound is due to what?

Closure of the pulmonary and aortic valves

13

3rd heart sound occurs when?

After the 2nd heart sound and is seen in congestive heart failure

14

The 4th heart sound is heard when?

Before the 1st heart sound and is seen in hypertrophic ventricles

15

Systole (contraction) occurs between which heart sounds?

1st and 2nd

16

Diastole (relaxation) occurs between which heart sounds?

2nd and 1st

17

If there is a prolonged PR interval (>200 milliseconds)

1st degree AV block

18

If there is progressive prolongation of the PR interval with dropped beats

2nd degree AV block (Mobitz 1- Wenckebach phenomenon)

19

Isovolumic contraction occurs when?

Between the closure of the AV valves and the opening of the aortic valve

20

Increase in pressure without change in volume is called what?

Isovolumic contraction

21

What is it called when only 70ml of the 120ml of blood is expelled from the ventricle?

Ejection fraction

22

A decrease in the ventricular pressure without a change in the volume is called?

Isovolumic relaxation

23

When does isovolumic relaxation occur?

Between the closing of the aortic valve and the opening of the AV valves

24

Sympathetic control of heart rate comes from which vertebral levels and which sympathetic ganglia?

T1-T5, middle and inferior cervical ganglia

25

What is it called when the sympathetic nervous system increases heart rate?

Positive chronotropism

26

How does the sympathetic nervous system increase the heart rate?

By increasing the rate of Phase 4

27

What is it called when there is an increase in conduction velocity?

Positive dromotropism

28

How does the sympathetic nervous system increase conduction velocity?

By decreasing the PR interval

29

What is it called when there is an increase in force of contraction in the heart?

Positive inotropism

30

How does the sympathetic nervous system increase force of contraction?

By increasing Ca++ influx in Phase 2

31

Which CN controls parasympathetic control to the heart?

Vagus through its cardiac branches

32

Cardiac Output x Peripheral Resistance = ?

Blood Pressure

33

Stroke Volume x Heat Rate = ?

Cardiac Ouput

34

Afferent high pressure sensors (baroreceptors) information in the carotid sinus are carried in which nerve?

Cranial nerve IX

35

Afferent high pressure sensors (baroreceptors) information in the aortic arch is carried in which nerve?

Cranial nerve X

36

CN IX and CN X carry afferent high pressure baroreceptor information to which area of the brain?

The Medulla

37

Where are the low pressure baroreceptors located?

SVC, IVC and the right atrium

38

What do low pressure baroreceptors monitor?

Volume

39

What is Poiseuille's Law?

Peripheral resistance is directly proportional to viscosity of blood and lenth of the vessel and inversely proportional to the radius of the vessel raised to the 4th power

40

The greatest resistance in the vascular system is offered where?

Arterioles

41

Blood flow through a tubular structure is governed by which law?

La Place's law

42

What is La Place's law?

The pressure within a blood vessel is related to the tension, size and shape of the vessel

43

What is blood flow inversely proportional to?

The diameter of the blood vessel

44

How much of the total blood volume is contained within the venous system?

60%

45

How much of the total blood volume is contained within the pulmonary system?

15%

46

How much of the total blood volume is contained within the capillaries?

5%

48

Where is blood flow the greatest?

Within the arteries and veins

49

Where is the least amount of blood flow?

The capillaries

51

How much of the total blood volume is contained within the arteries and arterioles?

20%

52

Pressure which tends to force fluids out into the interstitial space (+)

Intracapillary hydrostatic

53

Pressure which tends to pull fluids into the capillary (-)

Intracapillary oncotic pressure

54

Pressure which forces fluids into the capillary

Interstitial hydrostatic pressure

55

Pressure which pulls fluid out of the capillary

Interstitial oncotic pressure

56

Prolonged exercise leads to cardiac muscle hypertrophy which leads to?

Athletic Heart Syndrome