Anatomy_ heart pump physiology

Question 1

What are the main arteries in the heart?

Answer 1

Left main CA

Right main CA

Question 2

List the layers of the arterial walls (from superficial to deep):

Answer 2

Tunica adventitia
Tunica media
Tunica intimia

Question 3

In contrast to skeletal muscle, heart muscle cannot _______ ? why?

Answer 3

• tetanize; due to phase 2 of AP (plateau)
  Inward movement of

-Ca2+ sustains depolarization longer than skeletal muscle

Question 4

What sets fiber length in Heart?

Answer 4

Left ventricular- EDV or preload

Question 5

Define end diastolic volume (EDV):

Answer 5

volume of blood in the ventricle at the end of filling (diastole)

Question 6

Define end systolic volume (ESV):

Answer 6

volume of blood left in the ventricle at the end of contraction (systole)

Question 7

Define stroke volume (SV):

Answer 7

SV is the volume (mL) of blood ejected from the left ventricle with each contraction

Question 8

What are the determinants of SV?

Answer 8

Preload, afterload, contractility

The difference between EDV and ESV (EDV-ESV)

Question 9

What measurement is the best indicator of heart performance and disease prognosis?

Answer 9

Ejection fraction

Question 10

What are the determinants of EF?

Answer 10

Stroke volume divided by EDV

Question 11

What is a normal EF?

Answer 11

50-75%

LV norm: 62%

Question 12

Define cardiac output (CO):

Answer 12

the volume of blood ejected from the left ventricle every minute

Question 13

What are the determinants of CO?

Answer 13

HR x SV

Question 14

Define preload:

Answer 14

diastolic filling of the left ventricles

Question 15

Define afterload:

Answer 15

the resistance to emptying during contraction. The pressure the LV must generate to squeeze blood into the aorta

Question 16

What does the Frank Starling Law of the heart?

Answer 16

the FS law suggests that the heart will contract with greater force when preload (EDV) is increased; length-tension principle.

Question 17

Define myocardial contractility:

Answer 17

the squeezing contractile force that the heart can develop at a given preload or cardiac stretch

Question 18

What regulates an increase in myocardial contractility?

Answer 18

• beta- sympathetic adrenergic nerve activity (most influential)
• catecholamines (epinephrine norepinephrine)
• amount of contractile mass
• Drugs can alter (e.g., digitalis, sympathomimetics)

Question 19

What determines preload or EDV?

Answer 19

venous return

Question 20

What factors can decrease myocardial contractility?

Answer 20

• loss of contractile mass - myocardial Infarction
• myocardial muscle disease - cardiomyopathy
• drugs: anesthetics, barbiturates

Question 21

Define systolic blood pressure (SBP):

Answer 21

pressure measured in brachial artery during systole (ventricular emptying and ventricular contraction period)

Question 22

Define diastolic blood pressure (DBP):

Answer 22

pressure measured in brachial artery during diastole (ventricular filling and ventricular relaxation)

Question 23

Define mean arterial pressure (MAP):

Answer 23

“average” pressure throughout the cardiac cycle against the walls of the proximal systemic arteries (aorta)

Question 24

How is MAP measured?

Answer 24

.33 x (SBP-DBP) + DBP

Question 25

Define total peripheral resistance (TPR):

Answer 25

the sum of all forces that oppose blood flow

Question 26

What are the determinants of total peripheral resistance?

Answer 26

length of vasculature
blood viscosity
vessel radius

Question 27

What does the right main CA branch into?

Answer 27

marginal artery and posterior interventricular artery

Question 28

What does the left main CA branch into?

Answer 28

anterior descending artery and circumflex artery