Week 8: Cardiology Flashcards Preview

Med 1 UBC Fall 2019 > Week 8: Cardiology > Flashcards

Flashcards in Week 8: Cardiology Deck (51)
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1

Purpose of His-Purkinje System and bundle branches

To coordinate contraction of left and right ventricles

2

Which vessels provide the major resistance in the vascular tree?

The arterioles.
They have smooth muscle that is subject to autonomic control. Because they are small and arranged in series, a small alteration to radius makes a large (^4) difference for resistance.

3

3 main epicardial arteries

Right coronary artery
Left main coronary artery, which divides into the left anterior descending artery and the left circumflex artery.

4

Three functions of pericardium

1. Cardiac mechanics
2. Lubrication with cardiac motion
3. Barrier for limiting infections

5

3 main layers of heart

endocardium
myocardium
visceral pericardium - pericardial cavity - parietal pericardium

6

Composition of a sarcomere in cardiac muscle

thin filament (actin-troponin-tropomyosin) and thick filament (B myosin) with subtypes specific to cardiac muscle.

7

What is the mechanism of cardiac contraction at the cellular level?

calcium-induced calcium release (excitation-contraction coupling). This is unique to cardiac sarcomere.

8

What kind of valves are the aortic and pulmonary valves?

Semilunar

9

What two events delineate the beginning and end of systole?

AV valve closure and semilunar valve closure. I.e., S1-S2

10

Equation for cardiac output

CO = SV x HR

11

Equation for BP

BP = CO x SVR

12

Define stroke volume

The volume of blood ejected from the ventricle with each contraction

13

Define cardiac output

The volume of blood ejected from the ventricle per minute

14

Define vascular resistance

The resistance conferred by the vessels that must be overcome by ventricular contraction

15

What is the S1 sound?

Mitral valve and tricuspid valve closure

16

What is the S2 sound?

Pulmonary valve and aortic valve closure

17

S3 sound

An abnormal heart sound that, if present, occurs in diastole. Occurs when the ventricle is volume overloaded, whereby the rapid cessation of blood flow early in diastole (as the atrial and ventricular pressure equilibrate) results in an abnormal heart sound.

18

S4 Sound

An abnormal heart sound that, if present, occurs late in diastole. Occurs in pressure overloaded ventricle, whereby the extra pressure and volume conferred by atrial contraction into a stiff ventricle results in an abnormal heart sound.

19

What is a murmur?

Increased turbulent flow.

20

What are the three increased flow states that may be associated with a murmur?

1. Increased flow through normal structures in the context of increased metabolic demand
2. Turbulent flow through narrow orifices (narrowed valve, regurgitation, septal defect)
3. Flow into a larger distal chamber (aortic aneurysm)

21

When does pulmonic stenosis cause a murmur

Systole

22

When does mitral stenosis cause a murmur

During diastole

23

How can anemia cause a murmur?

Increased flow through normal structures.

24

when would aortic regurgitation make a murmur?

During diastole

25

What pressure difference signals the aortic valve to open?

When the LV pressure exceeds the aortic pressure

26

what is the ejection fraction?

Used to assess systolic function.

= SV / LV end-diastolic volume

27

Three determinants of stroke volume?

Preload
Afterload
Contractility

28

Define preload

the ventricular wall tension developed at the end of diastole. Closely approximates LVEDV (left ventricular end diastolic volume)

29

Define afterload

the ventricular wall stress encountered during contraction (systole) that must be overcome in order to eject blood.

30

What does increasing preload do to stroke volume?

Increased stroke volume (start with a push)