McCumbee - Regulation Of Cardiac Function

Question 1

Location of primary regulatory areas of cardiovascular function

Answer 1

Medulla

Question 2

Integrative area for coordinating various cardiovascular responses

Answer 2

Hypothalamus

Question 3

Modulates cardiovascular function by means of projections into the integrative areas of the hypothalamus

Answer 3

Cerebral cortex

Question 4

Sensory area located in the ________ has interneurons which modulate activity of cardiac inhibitory, cardiac accelerator, and vasoconstrictor areas

Answer 4

Nucleus tractus solitarius

Question 5

Sensory fibers going to the nucleus tractus solitariues come from ?

Answer 5

Baroreceptors and chemoreceptors

Question 6

Contains neurons involved in controlling sympathetic output to the heart and blood vessels.

Answer 6

Rostral ventrolateral medulla

Question 7

An increase in teh activity of the nucleus tractus solitarius will _______ vagal efferent activity and decrease sympathetic efferent activity

Answer 7

Increase

Question 8

Stimulation of areas within the rostral ventrolateral medulla stimulates

Answer 8

Vasoconstriction, tachycardia, and cardiac contractility

Question 9

Neurons controlling sympathetic output to the heart and blood vessels (in the RVLM) are tonically active. Inhibitory interneurons from the _____ inhibit the tonically activated neruns

Answer 9

Nucleus tractus solitarius

Question 10

When the dorsal vagal nucleus and the nucleus ambiguus of the medulla are electrically stimulated, they elicit

Answer 10

Bradycardia

Question 11

Cardioinhibitory center (stimulation elicits bradycardia)

Answer 11

Dorsal vagus nucleus and nucleus ambiguus

Question 12

The nuclei that make up the cardioinhibitory center are the

Answer 12

Dorsal vagal nucleus and the nucleus ambiguus

Question 13

What accounts for the fact that the normal heart rate is well below the intrinsic firing rate of the SA node?

Answer 13

The tonically active state of the cardioinhibitory center (nucleus ambiguus and dorsal vagal nucleus) which at baseline is causing bradycardia

Question 14

Parasympathetic innervation that goes to the heart comes from the dorsal vagal nucleus and nucleus ambiguus of the medulla. The ganglia for there are near __

Answer 14

The SA and AV nodes

Question 15

The right vagus primarily inhibits the

Answer 15

SA node

Question 16

The left vagus primarily inhibits the ____-

Answer 16

AV node

Question 17

____ muscle is innervated by vagal efferents, whereas the ______ myocardium has only sparse vagal innervation

Answer 17

Atrial

Ventricular

Question 18

Parasympathetic Postganglionic fibers mediate vagal action by releasing _______

Answer 18

Acetylcholine

Question 19

Why does parasympathetic postganglionic innervation decay rapidly in the SA and AV nodes?

Answer 19

It uses ACh, and there is a high cholinesterase concentration around those nodes which acts to break down the stimuli

Question 20

Neurons within the _____ have a tonic stimulatory effect on the heart and blood vessels

Answer 20

RVLM

Question 21

In the heart, postganglionic sympathetic adrenergic nerves innervate

Answer 21

The SA and AV nodes, conduction pathways and myocardium

Question 22

What type of stimulation to the heart decays faster, sympathetic or parasympathetic?

Answer 22

Parasympathetic.

Question 23

The vasoconstrictor effects of sympathetic nerves to blood vessels are mediated by _________ fibers

Answer 23

Noradrenergic

Fibers that release norepinephrine

Question 24

Most important adrenergic receptor w/ respect to modulating cardiac function

Answer 24

Beta -1

Question 25

Adrenergic receptors that are found in the heart

Answer 25

Beta-1
Beta-2
Alpha-1

Question 26

Order of functional potency in adrenergic receptors in the heart ?

Answer 26

Beta1 > beta2 > alpha1

Question 27

In the heart, ACh binds to ________

Answer 27

M2 Muscarinic receptors

Question 28

In the heart, activation of M2 muscarinic receptors (by the binding of ACh) induces dramatic NeGaTivE _____ and _____ effects

Answer 28

Chronotropic and dromotropic

Also induces a modest negative inotropic effect, mostly on the atria

Question 29

Sympathetic stimulation of the heart induces positive

(This is by norepinephrine binding beta1 and beta2 and alpha1 receptors_

Answer 29

Positive chronotropic, inotropic, and dromotropic effects

Question 30

What is atropine?

Answer 30

A muscarinic receptor antagonist. So it blocks the binding of muscarinic receptors by ACh, keeping there from being parasympathetic response to the heart, with the net result of increasing inotropy, chronotropy, and dromotropy.

Question 31

What is propranolol?

Answer 31

A beta-adrenergic receptor antagonist. Blocks binding of norepinephrine to beta 1, beta2 receptors. This results in a net decrease in chronotropy and dromotropy, and inotropy.

Question 32

What are baroreceptors?

Answer 32

Stretch receptors found in the walls of the heart and blood vessels and are stimulated by distention.

Abundant in carotid sinus and aortic arch

Question 33

Impulses from the baroreceptors in the carotid sinus are transmitted to the nucleus tractus solitarius of the medulla via the ?

Answer 33

Glossopharyngeal nerve

Question 34

Impulses from the baroreceptors in the aortic arch are transmitted by ?

Answer 34

The vagus nerve

Question 35

Baroreceptors are tonically active. Baroreceptor firing ______ with increasing blood pressure and _______ with decreasing blood pressure

Answer 35

Increases

Decreases