CV Physiology 1, Hassid

Question 1

Cardioacceleratory center

Answer 1

sympathetic

Question 2

Cardioinhibitory center

Answer 2

parasympathetic

Question 3

parasympathetics innervate the heart via the

Answer 3

vagus nerve

Question 4

the _____ vagus nerve ends at the SA node

Answer 4

left

Question 5

the _____ vagus nerve ends at the AV node

Answer 5

right

Question 6

conduction system in the heart

Answer 6

SA node -> Internodal pathways -> AV node -> AV bundle -> Bundle branches -> Purkinje fibers

Question 7

pacemaker of the heart

Answer 7

SA node

Question 8

conduction slows as it goes through the

Answer 8

AV node

Question 9

ventricles do not depolarize _____ in health

Answer 9

spontaneously

Question 10

_____ is the resting stable electrical potential of ventricular myocytes

Answer 10

phase 4

Question 11

Phase _ is a rapid depolarization

Answer 11

0

Question 12

Phase _ a small variable repolarization

Answer 12

1

Question 13

Phase _ maintains the cells in a depolarized state

Answer 13

2

Question 14

Phase _ is the bulk of the repolarization

Answer 14

3

Question 15

__ channels maintain the ventricular myocytes in a hyperpolarized state (Phase 4)

Answer 15

K (specifically IK1

Question 16

The ___ channel slightly repolarizes the ventricular myocyte in phase 1.

Answer 16

ITO (transient outward)

Question 17

These two ion channels balance the electrical potential in ventricular myocytes during phase 2

Answer 17

Ca and K

Question 18

K channels active in hyperpolarized cells

Answer 18

IK1, IKATP, IKAch

Question 19

K channels active in depolarized cells

Answer 19

IKur, IKr, IKs

Question 20

_____ and _____ have essentially the same electrical activity as the ventricular muscle

Answer 20

bundle branch and purkinje fibers

Question 21

There is no plateau in the electrical potential in the _____, _____, and _____.

Answer 21

SA node, Atrial muscle, and AV node

Question 22

SA nodes are just a trigger so they do not need to

Answer 22

maintain depolarization

Question 23

When the SA node cells reach their polarized state, __ channels close and __ channels open

Answer 23

K; If (sodium)

Question 24

In the SA node, __ channels close and __ channels open at threshold.

Answer 24

If (sodium); Ca

Question 25

maximum conduction rate in the heart occurs in the _____ and the _____

Answer 25

Bundle of His; Purkinje cells

Question 26

The slowest conduction rate in the heart occurs in the _____ and the _____

Answer 26

SA node; AV node

Question 27

Absent any outside influences, the spontaneous discharge rate of the SA node would be

Answer 27

100-120 bpm

Question 28

The _____ and the _____ only have spontaneous activity if they are damaged.

Answer 28

atrial muscle; ventricular muscle

Question 29

There is spontaneous activity in the _____, _____, and _____ but at a lower rate than the SA node (but they are only activated if the SA node is blocked).

Answer 29

AV node; Bundle of His; Purkinje cell

Question 30

A decrease in HR, decrease in conduction velocity (particularly in the AV node), and decreased excitability of latent pacemakers are all consequences of _____ activity.

Answer 30

parasympathetic

Question 31

An increase in HR, increase in conduction velocity (particularly in the AV node), decreased threshold of Ca channels (thereby increasing the excitability of latent pacemakers and other cells) are all consequences of _____ activity.

Answer 31

sympathetic

Question 32

The strength of contraction is regulated by _____ and _____.

Answer 32

intracellular Ca levels during action potential; initial length of cardiac fibers

Question 33

Activation of the _____ receptor causes release of Ca from the sarcoplasmic reticulum.

Answer 33

ryanodine receptor

Question 34

2 mechanisms that drive calcium out of the cells.

Answer 34

ATP-driven calcium pump (most important) | Na/Ca antiporter

Question 35

Ca is pumped back into the SR via an

Answer 35

ATP-driven pump

Question 36

3 most abundant catecholamines in the human body

Answer 36

Epinephrine Norepinephrine Dopamine

Question 37

Epinephrine or Norepinephrine-triggered events leading to increased Ca levels in the cells and increased uptake into the SR

Answer 37

binds to beta-adrenergic receptor (cell membrane) -> ... -> activation of adenylyl cyclase -> cAMP levels increase -> activation of PKA -> phosphorylation (activation) of cell membrane Ca channels and the ryanodine receptor (SR) and inhibition (via phosphorylation) of phospholamban which is an inhibitor of the Ca ATP pump into the SR

Question 38

Catecholamines accelerate the rate of these 3 things in cardiac myocytes.

Answer 38

``` cardiac contraction (inotropy) intracellular calcium decline cardiac relaxation (lusitropy) ```

Question 39

Acetylcholine inhibits ____, causing _____

Answer 39

adenylyl cyclase; the opposite effects of catecholamines

Question 40

preload equals

Answer 40

end diastolic volume

Question 41

EDV-ESV=

Answer 41

SV

Question 42

2 responses to stretch that translate into increased cardiac force generation.

Answer 42

Fast response to stretch: increased Ca sensitivity of myofilaments by stretch Slow response to stretch: activation of Ca channels by stretch