Cardio Physiology - Fundamentals

Question 1

What are the autonomic innervations of Arterioles

Answer 1

1. Activation of Alpha-1 adrenergic receptors in arterioles of skin and other vascular beds result in constriction
2. Activation of Beta-2 adrenergic receptors found on skeletal muscles result in dilatation.

Question 2

Vascular Resistance is altered by what?

Answer 2

Sympathetic nervous activity and vasoactive substances. This result in a modified “sympathetic tone” to blood vessels which may increase or decrease resistance thereby modifying blood flow.

Question 3

What is the Compliance Equation?

Answer 3

Compliance = Volume / Pressure

Question 4

What are the consequences of decreased venous compliance?

Answer 4

Decreased capacitance and blood shift to the arterial side of the circulation.

Question 5

What are the consequences of increased venous compliance?

Answer 5

Increased venous compliance and blood shift to the venous side of circulation.

Question 6

What would increased sympathetic tone do to compliance?

Answer 6

Smooth muscle contraction, reducing the “capacitance” or decreasing compliance.

Question 7

What do “vaso active” substances do?

Answer 7

Nitroglycerin can increase “capacitance” or increase compliance.

Question 8

Where is blood flow fastest?

Answer 8

Large arteries

Question 9

Where is blood flow slowest?

Answer 9

Capillaries

Question 10

What is the greatest factor effecting resistance in a vessel?

Answer 10

Radius. Increase the radius and decrease the resistance.

Question 11

Cardiac mur-mur and aortic stenosis do what to blood flow?

Answer 11

Increase blood flow. Both create non-laminar flow.

Question 12

Pulse Pressure Equation

Answer 12

Systolic - Diastolic pressure

Question 13

MAP Equation

Answer 13

Diastolic + 1/3 Pulse Pressure

Question 14

Pressure in Aorta?

Answer 14

100

Question 15

Pressure in large arteries?

Answer 15

100

Question 16

Pressure in arterioles?

Answer 16

50

Question 17

Pressure in systemic capillaries?

Answer 17

20

Question 18

Pressure in Vena Cava?

Answer 18

4

Question 19

Pressure in right atrium?

Answer 19

0-2

Question 20

Pressure in pulmonary artery?

Answer 20

15 (sys-25 & dia-8)

Question 21

Pressure in venous capillaries?

Answer 21

10

Question 22

Pressure in pulmonary vein?

Answer 22

8

Question 23

Pressure in left atrium?

Answer 23

2-5

Question 24

What happens in S-2 and what id the order?

Answer 24

Aorta closes just before Pulmonic

Question 25

What happens in S-1?

Answer 25

Mitral and Tricuspid valves close. | AV-valves

Question 26

Sequence of normal electrical conduction in heart?

Answer 26

SA node, Inter-nodal Tracts (rapid), AV node (slow), Bundle of His (rapid), Right/Left bundle branches (rapid), Purkinje (rapid), Ventricles

Question 27

What is a positive chronotropic effect?

Answer 27

Increased heart rate (through Beta-1 sympathetic stimulation)

Question 28

What is a negative chronotropic effect?

Answer 28

Decreased heart rate (through parasympathetic stimulation)

Question 29

SA Node intrinsic rate?

Answer 29

70-80

Question 30

AV Node intrinsic rate?

Answer 30

40-60

Question 31

Bundle of His intrinsic rate?

Answer 31

40

Question 32

Purkinje fibers intrinsic rate?

Answer 32

15-20

Question 33

When would the "other" pacemakers (AV etc.) take over?

Answer 33

Vagal tone and "heart block"

Question 34

Magnitude of tension developed by myocardial cells is proportional to what?

Answer 34

Proportional to intracellular Ca++ concentration.

Question 35

What does a faster heart rate do to myocardial muscle tension?

Answer 35

Increase because there is more cytoplasmic Ca++ at faster heart rates.

Question 36

What does a Positive Inotrope do?

Answer 36

Increase "contractility"

Question 37

What does a Negative Inotrope do?

Answer 37

Decrease "contractility"

Question 38

Example of Positive Inotrope

Answer 38

Sympathetic stimulation by epinephrine and sympathomimetics. Stimulate Beta-1 at both Atria and Ventricles.

Question 39

Example of Negative Inotrope

Answer 39

Parasympathetic stimulation can decrease Atria Contractility Sympatholytic drugs such as "Beta Blockers". Direct myocardial depression with "Ca++ Channel Blockers"

Question 40

What is the "Positive Staircase Effect"?

Answer 40

Increases in heart rate produce an increase in contractility, because greater amount of free Ca++ in the ICF.

Question 41

FORCE of ventricular contraction is a function of what?

Answer 41

End diastolic length of cardiac muscle.

Question 42

What is After Load?

Answer 42

Aortic Pressure. What the heart has to pump against in order to eject blood.

Question 43

What is Ejection Fraction?

Answer 43

The percent of blood in the ventricle at the end of diastole, that is ejected with a single beat.

Question 44

What can cause SA node arrest?

Answer 44

A burst of Parasympathetic Tone.

Question 45

How much stroke volume does the Atria contribute?

Answer 45

20%

Question 46

Cardiac Work Equation

Answer 46

Work = Stroke Volume x Aortic Pressure

Question 47

What is a common cause of Ventricular Hypertrophy?

Answer 47

Hypertension

Question 48

What happens to pressure generation in Ventricular Hypertrophy?

Answer 48

Less pressure as the chamber walls get bigger.

Question 49

How to treat Ventricular Hypertrophy

Answer 49

Treat HTN, Decrease contractility with Beta-Blockers, Ca++ channel blockers, Other, see notes...