Cardiovascular Physiology - HP

Question 2

What is the outer layer of the heart called?

Answer 2

Pericardium/Epicardium

Question 3

What is the middle layer of the heart composed of?

Answer 3

Myocardium, composed of cardiomyocytes (contractile cells)

Question 4

What is the inner layer of the heart called?

Answer 4

Endocardium

Question 5

What are the characteristics of the atria?

Answer 5

Thinner walls

Question 6

What are the characteristics of the ventricles?

Answer 6

Thick muscular walls (Left ventricle thicker than right)

Question 7

What is the function of the pericardial cavity?

Answer 7

It provides a fluid-filled space that reduces friction between the heart and surrounding structures

Question 8

What do coronary arteries supply?

Answer 8

Blood to myocardium

Question 9

What can blockage or narrowing of coronary arteries lead to?

Answer 9

Heart disease

Question 10

Which vessel does the left ventricle pump blood into?

Answer 10

Aorta

Question 11

Which vessel does the right ventricle pump blood into?

Answer 11

Pulmonary artery

Question 12

Where does oxygenated blood come from in the heart?

Answer 12

Pumped out from the left ventricles

Question 13

What are autorhythmic cells?

Answer 13

Cells that generate pacemaker action potentials

Examples include Sinoatrial nodes.

Question 14

What characterizes the resting membrane potential in autorhythmic cells?

Answer 14

No stable resting membrane potential

Question 15

What is the pacemaker potential (phase 4) in autorhythmic cells?

Answer 15

Slow, spontaneous depolarization primarily due to the funny current (If)

Carried by Na+ and K+ ions.

Question 16

What contributes to the depolarization in pacemaker potential?

Answer 16

T-type Ca2+ channels

Question 17

What happens during depolarization/upstroke (phase 0) in autorhythmic cells?

Answer 17

Rapid depolarization occurs when the threshold potential is reached

Primarily mediated by L-type Ca2+ channels.

Question 18

What occurs during repolarization (phase 3) in autorhythmic cells?

Answer 18

K+ efflux through voltage-gated K+ channels

Question 19

What are contractile cells?

Answer 19

Cells that generate non-pacemaker action potentials

Examples include Ventricular Myocytes.

Question 20

What is the resting membrane potential (phase 4) in contractile cells?

Answer 20

Stable negative potential around -90 mV

Question 21

How is the resting membrane potential in contractile cells maintained?

Answer 21

By K+ leak channels and Na+/K+ ATPase pumps

Question 22

What occurs during phase 0 in contractile cells?

Answer 22

Rapid depolarization due to fast Na+ channels opening

Causes rapid Na+ influx.

Question 23

What is observed during phase 1 in contractile cells?

Answer 23

Early repolarization due to K+ efflux through transient outward K+ channels

Question 24

What characterizes phase 2 in contractile cells?

Answer 24

Plateau phase with balanced influx of Ca2+ and efflux of K+

Question 25

What happens during phase 3 in contractile cells?

Answer 25

Closure of Ca2+ channels and opening of additional K+ channels

Question 26

What are the key differences between autorhythmic cells and contractile cells?

Answer 26

* Autorhythmic cells have spontaneous depolarization * Contractile cells require external stimulation * Upstroke in autorhythmic cells is primarily due to Ca2+ influx * Upstroke in contractile cells is due to Na+ influx * Contractile cells have a distinct plateau phase * Action potential in contractile cells is longer (~300ms) compared to nerve or skeletal muscle (~2ms)

Question 27

Continue from EEC of a cardiac myocyte from my lecture notes