Faber - Cv Reg

Front 1

What is the difference between primary and secondary MAP reflexes and regulatory mechanisms?

Back 1

Primary reflexes maintain MAP constant; secondary reflexes acutely alter MAP.

Front 2

Where are the arterial baroreceptors located?

Back 2

In the carotid sinus bodies and the arch of the aorta.

Front 3

How is the firing rate of arterial baroreceptors related to MAP?

Back 3

They fire constantly in a rate that is directly related to vessel tension, and thus MAP. Increase in MAP increases firing, and a decrease in MAP decreases firing.

Front 4

How do afferent nerves arising from the arterial baroreceptors travel to the medulla?

Back 4

From the aortic arch they travel with the vagus (CN X), from the carotid sinus bodies they travel with the glossopharyngeal (CN IX)

Front 5

What does the medulla do when an increase in MAP is sensed?

Back 5

Decrease SNS stimulation, increase parasympathetic stimulation.

Front 6

What does the medulla do when a decrease in MAP is sensed?

Back 6

Increase SNS stimulation, decrease parasympathetic stim.

Front 7

What is the effective range of control for the baroreceptor reflex?

Back 7

50-200mmHg

Front 8

What are 5 things that SNS stimulation will do to increase MAP? What is the end result of each?

Back 8

1.Decrease venous CPL
2.Increase HR
3.Increase LV CTY
4.Increase release of angiotensin II
5.Increase Starling forces

Front 9

After a disturbance occurs, how long does it take for the baroreceptor to kick in? How long until compensation to nearly normal happens?

Back 9

Seconds to onset, 95% of normal by 30 seconds.

Front 10

What are the immediate and long effects of vasopressin? Under what MAP conditions is it released?

Back 10

It immediately increases SVR and lowers CPL. Over time it promotes retention in the kidney and increases volume. It is released when MAP is low.

Front 11

What parameter is the cardiopulmonary reflex based on?

Back 11

Indirectly on CVP.

Front 12

Where are the sensors for the cardiopulmonary reflex located?

Back 12

At the point where the IVC and SVC enter the RA and where the pulmonary veins enter the LA.

Front 13

How do afferent nerves from the cardiopulmonary sensors travel to the medulla?

Back 13

With the vagus (CN X)

Front 14

How do the cardiopulmonary sensors work?

Back 14

They fire with increasing frequency during atrial filling; rate of firing is thus proportional to CVP.

Front 15

What two factors determining CVP are most important to the cardiopulmonary reflex?

Back 15

*total blood volume
*venous CPL

Front 16

How would a decrease in CVP due to venous hemorrhage by corrected by the cardiopulmonary reflex?

Back 16

A decrease in sensor firing would be detected by the medulla which would increase SNS and decrease parasympathetic stim. Vasopressin and angiotensin II would be released.

Front 17

When does CVP pooling occur?

Back 17

In space and during prolonged bed rest.

Front 18

What occurs in CVP pooling?

Back 18

The lack of gravitational pressure causes blood to move from the periphery into the thorax, thus increasing CVP.

Front 19

How does the body react to CVP pooling?

Back 19

Cardiopulmonary sensors trigger decreased SNS and parasympathetic stim, and less release of angiotensin II and vasopressin. Output increases and volume decreases.

Front 20

What are the dangers of CVP pooling?

Back 20

The decrease in volume can accentuate orthostatic disturbances.

Front 21

What is cold diuresis?

Back 21

Low temp causes blood to be diverted from the periphery and results in CVP pooling.

Front 22

Describe a situation where the cardiopulmonary and baroreceptor reflexes might be antagonistic.

Back 22

In CHF, where MAP is low but CVP is high. The baroreceptors are generally the more powerful.

Front 23

What is the goal of the baroreceptor reflex? Of the cardiopulmonary reflex?

Back 23

Baroreceptor: maintain MAP.
Cardiopulmonary reflex: maintain CVP

Front 24

What is the primary function of the arterial chemoreceptor reflex?

Back 24

To control resp rate and depth - seeks to maintain arterial blood gases and pH.

Front 25

Where are the peripheral chemoreceptors located?

Back 25

In aortic and carotid bodies.

Front 26

What about the arterial chemoreceptors makes them particularly sensitive to ABG?

Back 26

They have the highest metabolic rate in the body.

Front 27

Specifically, what do peripheral chemoreceptors sense?

Back 27

Disturbances that lower PO2, raise PCO2, and lower pH.

Front 28

Where are the central chemoreceptors located? To what are they most sensitive?

Back 28

In the ventral medulla. They are most sensitive to PCO2 and pH in the interstitial fluid.

Front 29

T/F:
Arterial chemoreceptors can trigger an increase in sympathetic or parasympthetic stimulation.

Back 29

False: these are one-way receptors that stimulate only a rise in SNS stim. They are only active in times of low PO2, hi PCO2, and lo pH

Front 30

At what MAP does the cerebral ischemic reflex kick in?

Back 30

When MAP is no longer maintained by the baroreceptor reflex and falls below 50mmHg

Front 31

What is the action of the cerebral ischemic reflex? When does it stop?

Back 31

It causes a "super SNS stim". It stops if MAP and CBF continue to fall and cell death occurs in control centers.

Front 32

What are the hallmark signs of the cerebral ischemic reflex?

Back 32

Tachycardia (>200bpm) and low BP.

Front 33

When does the Cushing reflex occur?

Back 33

When ICP is sharply increased and CBF occluded (e.g. intracranial hemorrhage). The ensuing rise in PCO2 is sensed by central chemoreceptors.

Front 34

What is the action of the Cushing reflex?

Back 34

A "super SNS stim" which greatly increases MAP and HR.

Front 35

What are the hallmark signs of the Cushing reflex?

Back 35

Brachycardia, profound HTN, likely unconsciousness.