CV PHYSIO

Question 1

what are the phases of the cardiac cycle?

Answer 1

phase 1: atrial contraction
phase 2: isovolumetric contraction
phase 3: rapid ejection
phase 4: reduced ejection
phase 5: isovolumetric relaxation
phase 6: rapid filling
phase 7: reduced filling

Question 2

T/F, atrial contraction is responsible for total filling of the ventricles?

Answer 2

F, nope

Question 3

what percent of blood flows through the atria before the atria contract?

Answer 3

80%

Question 4

in certain conditions, like tachycardia, atrial contraction can contribute up to 40% of ventricular filing, this is called?

Answer 4

atrial kick

Question 5

pacemaker cells have the property of?

Answer 5

automaticity

Question 6

depolarization spreads to?

Answer 6

contractile myocytes

Question 7

dominant pacemaker of the heart? located where? what are the intervals?

Answer 7

SA node, upper posterior wall of RA, 60-100 bpm

Question 8

how does the impulse spread?

Answer 8

from the SA node throughout atria, through Bachman’s bundle to the LA, then through internodal pathways to the AV node

Question 9

what is the effect of the cardiac muscle staying contracted longer than skeletal muscle?

when the refractory period is longer?

Answer 9

enhances ejection of blood

ensures muscle relaxation before next contraction

Question 10

BP equals?

Answer 10

CO x SVR

Question 11

CO equals?

Answer 11

SV x HR

Question 12

stroke volume affected by?

Answer 12

ventricular preload
ventricular afterload
cardiac muscle contractility

Question 13

resistance of the arteriolar vessels?

Answer 13

depends on the radius of the vessels

Question 14

arterioles have basal tone (intrinsic tone)

they remain in a state of partial construction even when all external influences on them are removed

changes are affected by local, neural and hormonal mechanisms

Answer 14

autoregulation

Question 15

local regulation of vascular tone?

Answer 15

hypoxia
hypercapnia
acidosis
opening of precapillary sphincter

mediators: NO, prostaglandins, histamine, bradykinin

Question 16

afferent sensory information from the arterial baroreceptors enter the? then relayed where?

Answer 16

medullary nucleus tractus solitarius

medulla and hypothalamus

Question 17

efferent information leaves medulla from?

Answer 17

rostral ventrolateral medulla

Question 18

cell bodies of the preganglionic fibers are located where?

where do axons synapse on?

Answer 18

T1-T2 and exit the spinal cord in the ventral roots

paravertebral ganglia of sympathetic chain

prevertebral ganglia

chromaffin cells of the adrenal medulla

Question 19

major effects of norepinephrine on the B1 receptors in the heart?

Answer 19

positive chronotropic effect
positive inotropic effect
positive dromotropic effect
positive lusitropic effect