cardiovascular lecture 2

Question 1

what purpose does the prolonged refractory period of cardiac muscle serve? (2)

Answer 1

1. prevents tetanus

2. allows time for ventricles to fill with blood prior to pumping

Question 2

what activity does “cardiac output (CO)” reference?

Answer 2

the amount of blood moved per unit of time (ex. volume of blood each ventricle pumps per minute or the volume of blood flowing through either the systemic or pulmonary circuit per minute); heart rate (HR) x stroke volume (SV)

Question 3

route of blood through heart

Answer 3

right atrium –> tricuspid valve –> right ventricle –> pulmonary semilunar valve –> pulmonary trunk –> pulmonary arteries –> lungs –> pulmonary veins –> left atrium –> bicuspid valve –> left ventricle –> aortic semilunar valve –> aorta

Question 4

what causes the first heart sound (“lub”)

Answer 4

closure of the AV valves

Question 5

what causes the second heart sound (“dub”)

Answer 5

closure of the aortic and pulmonary valves

Question 6

what are 3 conditions associated with a heart murmur

Answer 6

1. stenosis (narrowing)
2. regurgitation (insufficiency)
3. septal defects

Question 7

a stenotic valve/turbulent flow can be heard during systole or diastole?

Answer 7

systole

Question 8

turbulent backflow can be heard during systole or diastole?

Answer 8

diastole

Question 9

what does it mean when an electronic circuit is “in series”

Answer 9

components are connected end to end to form only one path for electrons to flow through the circuit

Question 10

what does it mean when an electronic circuit is “parallel”

Answer 10

components are connected between the same two sets of electrically common points, creating multiple paths for electrons to flow

Question 11

T/F: Systemic and pulmonary circulations are parallel

Answer 11

FALSE; they are in series; this allows for all of the blood to become oxygenated

Question 12

T/F: organs in systemic circulation are in parallel

Answer 12

TRUE; this allows for each organ to receive 100% O2

Question 13

Flow equals what

Answer 13

change in pressure/resistance (F=change in P/R)

Question 14

during systole, are the ventricles relaxing or contracting?

Answer 14

contracting

Question 15

during diastole, are the ventricles relaxing or contracting?

Answer 15

relaxing

Question 16

wiggers diagram

Answer 16

PDF on carmen. Know it

Question 17

T/F: the right side of the heart and the left side of the heart have the same stroke volume and cardiac output

Answer 17

TRUE; the only difference is the pressure generated

Question 18

what kind of innervation/control does the atria have?

Answer 18

1. Parasympathetic: muscarinic receptors (acetylcholine)

2. Sympathetic: beta-adrenergic receptors (NE)

Question 19

what kind of innervation/control does the ventricle have

Answer 19

Sympathetic ONLY (Ziolo yelled this at us like 800 times); beta-adrenergic receptors (EPINEPHRINE)

Question 20

under sympathetic control, what happens to the pacemaker potentials of the heart

Answer 20

they occur more quickly than under control circumstances (slide 27 for graph)

Question 21

under parasympathetic stimulation, what happens to the pacemaker potentials of the heart

Answer 21

they occur more slowly than under control circumstances (slide 27 for graph)

Question 22

what are 3 major ways to increase/speed up the heart rate

Answer 22

1. deliver sympathetic hormone epinephrine
2. release more sympathetic NT, NE
3. reduce release of PS NT, acetylcholine

Question 23

what are 3 major factors influencing SV

Answer 23

1. Preload: the end- diastolic volume aka the volume of blood in the ventricles just before contraction
2. magnitude of sympathetic input to the ventricles
3. Afterload: the pressure against which the ventricle pumps

Question 24

Frank-Starling mechanism aka ventricular function curve

Answer 24

plots the ventricular end-diastolic volume against the stroke volume; Frank Starling measures the PRELOAD, NOT contractility

Question 25

how do you increase the heart's stroke volume? how do you further increase it?

Answer 25

fill it more fully with blood --> increased stretch of ventricle will align actin and myosin in a more optimal pattern of overlap; to further increase it, deliver sympathetic signals ie NE and epi --> will also cause heart to relax more rapidly and allow more time to refill

Question 26

increased contractility is due to what

Answer 26

sympathetic stimulation and an increase in Ca (slide 33, not sure what we need to know from the diagram)

Question 27

sympathetic signals ie NE and epi cause a stronger and more rapid contraction and what

Answer 27

a more rapid relaxation

Question 28

T/F: Parasympathetic nerves have a significant effect on the ventricular muscle

Answer 28

FALSE; the ventricle has NO parasympathetic innervation

Question 29

to increase SV, you can increase what

Answer 29

1. end-diastolic volume 2. NE delivery from sympathetic neurons 3. epinephrine delivery from adrenal medulla

Question 30

to incrase HR, you can increase what

Answer 30

1. NE delivery from symp neurons | 2. epinephrine delivery from the adrenal medulla aka reduce PS

Question 31

T/F: Under normal circumstances, it is possible to increase SV without increasing HR and vice versa

Answer 31

FALSE; it's not possible

Question 32

what is ejection fraction?

Answer 32

measurement of contractility; (EDV-ESV)/EDV **SV = EDV-ESV... **he said he "can see a question here"

Question 33

hypertrophic cardiomyopathy

Answer 33

increased heart wall thickness; myocardial disarray particularly in interventricular septum --> interferes with blood ejection (leads to angina, arrhythmias, and sudden cardiac death

Question 34

what is hypertrophic cardiomyopathy dependent on

Answer 34

preload