cardiovascular physiology

Question 1

what are inotrophy, chronotrophy, and dromotrophy

Answer 1

inotrophy (force of contraction)
chronotrophy (rate of contraction)
dromotrophy (conduction velocity)

Question 2

what are the terms for slow and fast heart beats

Answer 2

bradycardia - slow heartbeat

tachycardia - fast heartbeat

Question 3

what are the two types of cardiac muscle cells

Answer 3

conducting system cells (controls heartbeat)
contractile cells (produce contractions to move blood)

Question 4

what is automaticity of cardiac cells

Answer 4

the heart doesn’t need any external influence to beat, no nervous innervation or anything

Question 5

what is the resting potential of ventricular cells

Answer 5

-90 mv

Question 6

what is the resting potential of atrial cells

Answer 6

-80 mv

Question 7

what is the major ion in cardiac muscle

Answer 7

Ca

Question 8

what is the difference between the absolute refractory period and relative refractory period

Answer 8

aboslute refractory period comes before the relative refractory period, is long in duration, and the cardiac cells can’t respond to stimuli during it. during the relative refractory period muscle contractile cells can respond to stimuli, if it is strong enough

Question 9

what is the difference between cardiac and skeletal muscle refractory periods, and why is it important

Answer 9

the cardiac muscle refractory period is much longer than the skeletal, this keeps the heart cells from using summation to reach tetanus

Question 10

what are the structures though which the conducting system impulses pass beginning with the SA node and ending with contractile cells

Answer 10

SA node
internodal pathways
AV node
AV bundle
bundle branches
perkinje fibers
contractile cells

Question 11

what is another name for the prepotential

Answer 11

pacemaker potential ( a gradual spontaneous depolarization)

Question 12

how many action potentials do the SA and AV nodes produce per minute

Answer 12

SA node produces 80-100

AV node produces 40-60

Question 13

what do the P, Q, R, S, and T of an EKG represent

Answer 13

P - atrial depolarization
QRS - ventricular depolarization (atrial repolarization)
T - ventricular repolarization

Question 14

what does the P-R interval of the EKG represent

Answer 14

start of atrial depolarization to start of QRS complex (ventricular depolarization)

Question 15

what does the Q-T interval of the EKG represent

Answer 15

ventricular depolarization to ventricular repolarization

Question 16

what are the two phases of the cardiac cycle

Answer 16

systole (contraction)

diastole (relaxation)

Question 17

when do we have end-diastolic volume

Answer 17

its the volume in the ventricle right before it contracts (at the end of relaxation/diastole) maximum blood volume

Question 18

when do we have isovolumetric contraction

Answer 18

right after the AV valves close, and before the semilunar valves open

Question 19

what is the amount of blood ejected from the heart during one systole called

Answer 19

stroke volume

Question 20

when do we have end-systolic volume

Answer 20

after the ventricle has pumped out all the blood it can and the semilunar valve closes (end of systole) minimum blood volume

Question 21

what percentage of end-diastolic volume remains as end systolic volume

Answer 21

40%

Question 22

When do we have isometric relaxation

Answer 22

after the semilunar valves close, and before the AV valves open

Question 23

how do you find stroke volume

Answer 23

EDV-ESV

Question 24

what is cardiac output, and what influences it

Answer 24

volume pumped by left ventricle in one minute.

it is influenced by heart rate and stroke volume

Question 25

what determines heart rate

Answer 25

autonomic nervous system and hormones

Question 26

what nervous system increases heart rate

Answer 26

sympathetic nervous system

parasympathetic decreases heart rate

Question 27

what are the two cardiac centers in the medulla oblongata

Answer 27

cardioacceleratory (SNS)

cardioinhibitory (PNS)

Question 28

what nerves innervate the heart, and where do they come from

Answer 28

cardia plexus innervates the heart and comes from the vagus nerve

Question 29

where do you find, and what is the function of cholinergic receptors in the heart

Answer 29

they are found in the SA node mostly, and they reduce heart rate (parasympathetic)

Question 30

where do you find, and what is the function of adrenergic receptors in the heart

Answer 30

they are found in the SA node, and they increase heart rate and contraction force (sympathetic) and

Question 31

what is the effect of angiotensin

Answer 31

increase contractility

Question 32

what are the cardiac reflexes that control heart rate and contractility

Answer 32

baroreceptors that detect blood pressure

chemoreceptors that detect oxygen and CO2 levels

Question 33

what is the atrial reflex, or bainbridge reflex

Answer 33

heart rate adjusts to venous return. more venous return = quicker heart rate

Question 34

what two things affect EDV

Answer 34

filling time

venous return

Question 35

what three things affect ESV

Answer 35

preload
contractility
afterload

Question 36

what is the frank starling principle

Answer 36

as EDV increases SV increases (due to more volume and contractility)

Question 37

what keeps the heart from stretching too much

Answer 37

myocardial connective tissue
cardiac (fibrous)skeleton
pericardial sac