16: Cardiovascular Physiology

Question 1

EDV: where is equilibrium around?

Answer 1

125-150mL

Question 2

Why does the plateau occur in the venous return curve?

Answer 2

Plateau occurs due to collapse of veins entering chest

Question 3

CO equilibrium

Answer 3

Volume of blood at CO ejected by LV equals the volume it receives in venous return

Question 4

EDPVR and ESPVR stand for?

Answer 4

EDPVR: end-diastolic pressure-volume relationship
ESPVR: end-systolic pressure-volume relationship

Question 5

What causes increased afterload?

Answer 5

HTN, increased TPR, aortic stenosis, increased blood viscocity, increased intrathoracic pressure

Question 6

What causes increased contractility?

Answer 6

Adrenergic stimulation

Question 7

Compensation when preload/after load changes

Answer 7

After a few heart beats, the other will change to match

Question 8

Compensation when contractility changes

Answer 8

Changes in preload and afterload occur

Question 9

Three means of cardiac compensation

Answer 9

1. Renal (RAAS)
2. Natriuretic peptides
3. Symp and parasymp influence

Question 10

RAAS function for cardiac compensation

Answer 10

Raises blood volume to maintain BP

Question 11

What occurs with increasing level of BNP?

Answer 11

Risk of death increases

Question 12

Symp and parasymp effect on CO

Answer 12

Symp: increases contractility
Parasymp: decreases contractility

Question 13

Symp and parasymp receptors for CO changes

Answer 13

Symp: B-adrenergic receptors
Parasymp: muscarinic receptors

Question 14

Cascade of effects with symp activation

Answer 14

Phosphorylation of sarcolemma Ca channels + phospholamban + troponin I (inhibits)

Question 15

Parasymp activation cascade

Answer 15

Decreases inward Ca current during plateau -> + Ach increases outward K current

Question 16

Which type of work is costlier, volume or pressure work?

Answer 16

Pressure work

Question 17

Why does LV have to work proportionally harder than RV?

Answer 17

Systemic pressure is greater than pulmonary pressure

Question 18

How does heart failure cause edema?

Answer 18

Decreased CO + atrial pressure -> increased pulmonary venous and arterial pressures -> edema

Question 19

What does decreased pO2 cause in heart failure?

Answer 19

Dyspnea, respiratory alkalosis

Question 20

Two types of heart failure and what happens to EF

Answer 20

HRrER: systolic HF; EF is reduced
HRpER: diastolic HF, EF is unchanged

Question 21

Which part of the hear commonly fails in HRrEF?

Answer 21

LV

Question 22

What decreases and increases in HRrEF?

Answer 22

Increases: diastolic volume, BNP
Decreases: contractility

Question 23

What increases in HRpEF?

Answer 23

LV diastolic pressure, RA pressure

Question 24

What factors are increased, decreased, and unchanged with aortic stenosis

Answer 24

Increased: afterload
Decreased: SBP, pulse pressure
Unchanged: DBP

Question 25

What pressure increases in COPD?

Answer 25

Pulmonary mean arterial pressure

Question 26

What is right sided heart failure associated with?

Answer 26

Lung dysfunction; decreased gas exchange in pulmonary caps

Question 27

Three systemic effects of right sided heart failure

Answer 27

1. Increased systemic venous pressure -> edema
2. Liver function decreases
3. Decreased renal perfusion

Question 28

Where does pressure back up in mitral valve stenosis?

Answer 28

Increased pressure in LA -> backs up into pulmonary system

Question 29

S/S mitral valve stenosis

Answer 29

Pulmonary edema due to fluid in interstitial space, SOA