Neurohumoral Control Quiz 8

Question 1

Which sympathetic nerve receptor predominantly causes vasoconstriction?

Answer 1

Alpha

Question 2

Which sympathetic nerve receptor predominantly causes increased contractility?

Answer 2

Beta 1

Question 3

Which sympathetic nerve receptor predominantly causes bronchodilation?

Answer 3

Beta 2

Question 4

The definition of chronotropy

Answer 4

heart rate

Question 5

The definition of inotropy

Answer 5

contractility

Question 6

The definition of dromotropy

Answer 6

conduction velocity

Question 7

The definition of lusitropy

Answer 7

relaxation

Question 8

What are some of the major differences between the sympathetic and parasympathetic nervous systems?

Answer 8

Heart
Symp Paras
Chronotropy (rate) +++ - - -
Inotropy (contractility) +++ - 1
Dromotropy(conduction velocity)++ - - -

Vessels (vasoconstriction)
Resistance (arteries, arterioles)+++ - 2
Capacitance (veins) +++ 0

Question 9

Does the sympathetic nervous system primarily stimulate or inhibit the heart?

Answer 9

Stimulate

Question 10

What is the “second messenger” that is involved with sympathetic stimulation of a cardiac muscle cell?

Answer 10

Cyclic AMP

Question 11

Which catecholamine does the adrenal gland predominantly release with sympathetic stimulation?

Answer 11

Mostly epinephrine (80%)
lesser amount norepinephrine (20%)

Question 12

What is the Baroreceptor Reflex? Where are the receptors for this reflex located?

Answer 12

Sensor of change in BP, increases or decreases HR due to change. Located in carotid SINUS and Aortic Arch

Question 13

How does the Baroreceptor Reflex help with blood pressure regulation?

Answer 13

Senses and Buffers Change in BP

Reduces the daily variation in BP by 1/2 to 1/3 from that which would occur if this system were not present

Question 14

During what surgery does Baroreceptor Reflex activation frequently cause hemodynamic changes?

Answer 14

Carotid Endarectomy

Question 15

What is the Bainbridge Reflex? Where are the receptors for this reflex located?

Answer 15

Low pressure receptors that respond to stretch, sense cardiovascular system volume
(example, fluid bolus given to dog increases heart rate)
Located: Vena Cava- Right Atrial Junction
Pulmonary Vein- Left Atrial Junction

Question 16

In addition to receptor activation what also contributes to the heart rate changes seen with the Bainbridge Reflex?

Answer 16

Stretch of heart and Stretch of SA node

Question 17

The Baroreceptor Reflex responds to changes in arterial blood pressure or to changes in blood volume?

Answer 17

Changes in arterial blood pressure

Question 18

The Bainbridge Reflex responds to changes in arterial blood pressure or to changes in blood volume?

Answer 18

Changes in blood volume

Question 19

What are some of the effects of Atrial Stretch Receptor activation?

Answer 19

Increased Urine Output
Decreased H2O reabsorption
Decreased BP
Increased natriuresis

Question 20

What is the Bezold-Jarisch Reflex?

Answer 20

Strong contraction of an underfilled ventricle elicits the reflex, plays a role in blood pressure regulation, results in decreased BP and decreased HR

Question 21

What is the CNS ischemic response?

Answer 21

Result of decreased blood flow to vasomotor center in medulla, increases local concentration of CO2 results in SNS stimulation in medulla, which increases BP

Question 22

What is the Cushing Response?

Answer 22

Special type of CNS ischemic response, a result of increased ICP, results in increased BP until blood flows

Question 23

What is Cushing’s Triad?

Answer 23

Bradycardia
Increased BP
Increased ICP

Question 24

Under what circumstances can Peripheral Chemoreceptors cause hemodynamic changes? What hemodynamic changes occur?

Answer 24

Decreased arterial blood O2 tension, carbon dioxide excess, and or hydrogen ion excess results in the excitation of the vasomotor center, occurs from low blood pressure and inadequate blood flow to the chemoreceptors.

Increased MAP

Question 25

What is the Diving Reflex? What receptors are involved?

Answer 25

Cold water on face activates thermoreceptors, decreases HR and peripheral vasoconstriction causes reduced O2 consumption by the body and myocardium
Thermoreceptors

Question 26

An infusion of epinephrine will cause what changes in heart rate? Systolic blood pressure? Diastolic blood pressure?

Answer 26

Increases HR

Increases Systolic, Decreases Diastolic

Question 27

An infusion of norepinephrine will cause what changes in heart rate? Systolic blood pressure? Diastolic blood pressure?

Answer 27

Heart Rate will increase, then decreases

Increases Systolic and Diastolic BP

Question 28

Vasopressin is released from which part of the brain? What are the effects of vasopressin on blood pressure? What are the effects of vasopressin on the kidney?

Answer 28

Pituitary
Increases BP
Renal Fluid Reabsorption= increases blood volume

Question 29

What is the stimulus for release of Atrial Natriuretic Peptide? What are the effects of ANP on blood pressure?

Answer 29

Atrial Stretch/ Distention

Decreases BP

Question 30

What converts angiotensinogen to angiotensin I?

Answer 30

Renin

Question 31

What converts angiotensin I to angiotensin II?

Answer 31

ACE enzyme

Question 32

What are the INDIRECT effects of hypoxia on the circulatory system? What are the DIRECT effects?

Answer 32

Indirect- SNS activation, Increased HR, CO, Contractility

Direct= Depressed Myocardial Contractility

Question 33

What are the INDIRECT effects of hypercarbia on the circulatory system? What are the DIRECT effects?

Answer 33

Indirect- SNS activation, Increased HR, CO, Contractility

Direct= Depressed Myocardial Contractility