Heart and Circulation

Question 1

What are the two atrioventricular valves in the heart?

Answer 1

tricuspid (right)

bicuspid (left)

Question 2

What are the semilunar valves? What do they do?

Answer 2

pulmonary and aortic valves

- prevent backflor from aorta/pulm arteries into ventricles during diastole

Question 3

Which valves are open during systole?

Answer 3

semilunar: since blood is getting pushed out

Question 4

What is ESV?

Answer 4

End systolic volume: blood that’s left over in the ventricals after pumping blood out (~50ml)

Question 5

What is EDV?

Answer 5

End diastolic volume; how much blood is in ventricles after diastole (~120ml)

Question 6

What is diastole: what happens?

Answer 6

period of filling the ventricles: atria contract, semilunar valves are closed (AV valves open so ventricles can get filled)

Question 7

Atrial contraction accounts for how much of ventricle filling?

Answer 7

20-30%

Question 8

What are the two main arteries of coronary circulation, and where do they branch off of?

Answer 8

left and right coronary arteries, branching off of aorta

Question 9

The coronary arteries supply the heart muscle of course (ventricles/atrium), but what else that is essential to the heart?

Answer 9

conducting system

Question 10

An interruption of the circumflex artery would impact what side of the heart?

Answer 10

left ventricle/atrium

Question 11

What receives the deoxygenated blood used by the heart, and where does it dump into?

Answer 11

coronary sinus -> dumps into right atrium

Question 12

If myocardial oxygen supply is less than myocardial oxygen demand (MVO2), what can happen?

Answer 12

ischemia

Question 13

Describe the conducting system of the heart.

Answer 13

1) SA node: first node, at superior vena cava/right atrium jxn
2) AV node: at right atrium/right ventricle jxn
- into interventricular septum, where we go to:
3) Bundle of His -> RBB and LBB
4) Purkinje tissue/fibers in ventricles

Question 14

What is known as the main pacemaker of the heart?

Answer 14

SA node

Question 15

What is a normal stroke volume range?

Answer 15

55-100ml

Question 16

What does stroke volume depend on? (3)

Answer 16

1) preload (how much blood is in L ventricle after filling, aka LVEDV)
2) contractility (ability of L ventricle to contract)
3) afterload (the aortic pressure against which the L ventricle must overcome to pump blood out of the heart)

Question 17

How do you get cardiac output? (equation)

Answer 17

HR x SV = CO

Question 18

What is cardiac output?

Answer 18

the amount of blood discharged from the R or L ventricle per minute (time component)

vs SV: amount of blood ejected with each myocardial contraction (amount!!)

Question 19

What is a normal CO value?

Answer 19

4-5L /minute

Question 20

What is EF and what is a normal value?

Answer 20

EF = stroke volume/LVEDV
- % of available blood in LV that is pushed out for use

normal = >55%

Question 21

Does diastolic fill time increase or decrease with heart disease and increased HR?

Answer 21

decreases

Question 22

What is MVO2?

Answer 22

myocardial oxygen demand

Question 23

What causes MVO2 to increase?

Answer 23

activity, increased HR or BP

Question 24

What influences arterial pressure?

Answer 24

usually high pressure system
- can change based on peripheral resistance (are arteries dilated/contracted) and/or elasticity of vessels (think anneurism)

Question 25

What are capillaries?

Answer 25

small blood vessels that connect end of arteries (arterioles) with beginning of veins (venules) to form an anastomosing network

Question 26

Are capillaries permeable?

Answer 26

yes, function for exchange of nutrients and fluids between blood and tissues

Question 27

Where does lymph drain into?

Answer 27

venous circulation (subclavian veins)

• R lymphatic duct to R subclavian vein
• L thoracic duct to L subclavian vein

Question 28

T/F: lymph nodes contribute to the immune system

Answer 28

true

Question 29

What is a preventative measure for DVT when anticoags are contraindicated?

Answer 29

mechanical compression (ambulation, ankle pumps)

Question 30

When assessing for DVT, what should you be looking for?

Answer 30

red, warm, tender, leg circumference difference >3cm

active cancer, bedridden >3days/major surgery, entire leg swollen, collateral veins present

pitting edema, paralysis/immobilization tx to extremity, previous DVT

Question 31

A person who had major surgery should still be monitored for DVT for how many weeks?

Answer 31

4 wks