The Autonomic Nervous System II

Question 1

Includes a receptor (e.g. chemoceptors and baroceptors), afferent neurons to the CNS, usually one or more CNS interneurons, and pre- and post-ganglionic ANS efferents

Answer 1

An autonomic reflex

Question 2

Autonomic reflexes control several vital functions such as detecting changes in

Answer 2

Blood gases, BP, and volume status

Question 3

The electrical activity of the heart is regulated by the

Answer 3

ANS

Question 4

What are the effects on heart rate of

1. ) Elevated SNS tone
2. ) Elevated PSNS activity

Answer 4

1. ) Heart rate increases

2. ) Heart rate decreases

Question 5

The PSNS controls resting heart rate. What effect would down regulation of PSNS activity have?

Answer 5

Increase resting heart rate

Question 6

SNS innervation is abundant in the heart, where as PSNS innervation is sequestered to the

Answer 6

SA and AV nodal tissues

Question 7

The Nucleus of tractus solitarius (NTS), nucleus ambiguous (NA), and dorsal motror nucleus of the vagus (DMV) are specific nuclei in the medulla that are the origin of ANS control of

Answer 7

Cardiac Function

Question 8

The DMV and NA are subdivided into three key centers that control

Answer 8

HR and vasomotor function

Question 9

The DMV and NA are subdivided into three key centers that control HR and vasomotor function, these are the

Answer 9

1. ) Cardioacceleratory center
2. ) Cardioinhibitory center
3. ) Vasomotor center

Question 10

To increase SNS tone, which neurotransmitters activity is increased within the SNS regions of vasomotor and cardioacceleratory centers?

Answer 10

Glutamine and Substance P

Question 11

When glutamine and substance P are activated in the SNS cardioacceleratory and vasomotor centers, which neurotransmitter is activated in the PSNS cardioinhibitory centers?

Answer 11

The inhibitor GABA

Question 12

The result of this coordinated action is an

Answer 12

1. ) Increase in SNS tone

2. ) Decrease in PSNS tone

Question 13

What would we expect to see if we wanted to decrease HR and BP?

Answer 13

GABA and Substance P are upregulated in SNS cardioinhibitory and vasomotor centers respectively

Glutamine is upregulated in PSNS cardioacceleratory centers

Question 14

Within the heart, there are two specific regions of cardiac neuromuscular electrogenic tissue. What are they and where are they located?

Answer 14

1. ) SA node: in the right atrium

2. ) AV node: Junction between right and left atria and ventricles

Question 15

The SA node is expressed by

Answer 15

Type β1 adrenoreceptors and CM2

Question 16

The fundamental circuitry is as follows: ANS vagal efferents innervate the

Answer 16

SA node

Question 17

SA nodal activity controls

Answer 17

AV nodal activity

Question 18

AV nodal activity in turn initiates the depolarization of main conduction tracts (bundle of His and Purkinje fibers) that are coupled to

Answer 18

Ventricular myocytes

Question 19

Decreased blood volume induces a change in BP. BP drops below approximately 60 mm Hg. This is detected by the

Answer 19

Low pressure baroreceptors within the atria

Question 20

In response to the low BP, afferent (sensory) vagal fibers signal the ANS centers within the

Answer 20

C1 area of the medulla (cardioacceleratory center)

Question 21

Medullary fibers release excitatory neurotransmitters that then activate

Answer 21

SNS efferent

Question 22

Preganglionic SNS efferents form polysynaptic connections with post-ganglionic SNS efferents. These synapses are located within the

Answer 22

Nucleus of Tractus Solitarius, a part of C1

Question 23

Activation of cholinergic-nicotinic receptors within the post-synaptic membrane induces activation of

Answer 23

Ligand gated Na+ channels

Question 24

AP reaches the postganglionic nerve terminus and causes Ca2+-dependent release-coupling of vesicles containing

Answer 24

Norepinephrine

Question 25

Norepi binds and activates which two things?

Answer 25

1. ) a1 adrenoreceptors in vascular smooth muscle | 2. ) B1 adrenoreceptors in cardiac nodal and muscle tissue

Question 26

The ensuing combination of accelerated heart rate (chronotropy), increased cardiac contractile force (inotropy), and vasoconstriction will

Answer 26

Increase BP

Question 27

If high pressure baroreceptors are activated, sensory vagal and glossopharyngeal tracts running from the carotid sinus and aortic arch are activated. These fibers innervate

Answer 27

Inhibitory interneurons within the medulla (C1) region

Question 28

These inhibitory fibers suppress activity of the

Answer 28

SNS efferents

Question 29

Without SNS tone, there is an alleviation of

Answer 29

a1 vasoconstricitive response

Question 30

Concomitantly, populations of stimulatory interneurons induce activation of

Answer 30

PSNS preganglionic efferents

Question 31

Then post-ganglionic vagal efferents are activated; these fibers innervate cardiac SA nodal tissue; the result is a

Answer 31

Decrease in HR

Question 32

A rare catecholamine-secreting neuroendocrine tumor which arises from the adrenal medulla

Answer 32

Pheochromocytoma

Question 33

Usually secrete both epi and norepi in an episodic manner

Answer 33

Pheochromocytomas

Question 34

What are the effects of excessive 1. ) Norepinephrine 2. ) Epinephrine

Answer 34

1. ) Hypertension | 2. ) Tachyarrhythmias

Question 35

What can we measure to test for pheochromocytomas?

Answer 35

1. ) Plasma and urine catecholamines 2. ) Urinary metanephrines 3. ) Urine vanillylmandelic acid 4. ) Plasma-free metanephrines

Question 36

The level of plasma fractionated free metanephrines (normetanephrine and metanephrine) is the most sensitive test for

Answer 36

Secretory Pheochromocytomas

Question 37

Once identified and localized using MRI or CT scan, a | pheochromocytoma can often be surgically removed using

Answer 37

Laparascopy