Baroreceptor & Chemoreceptor Regulation

Question 1

What are vascular reflexes?

Answer 1

internal sensory-feedback systems that “sense” changes in important circulatory parameters and respond via pathways that alter the tonic autonomic control of the heart and vasculature

Question 2

Vascular reflexes work to maintain and optimize what?

Answer 2

cardiovascular performance in rpaidly changing physiological situations

Question 3

What are the types of vascular reflexes?

Answer 3

• peripheral baroreceptors
• peripheral chemoreceptors
• pulmonary stretch receptors
• hypothalamus

Question 4

What are arterial baroreceptors are present during?

Answer 4

• posture changes
• exercise
• hemorrhage

Question 5

Where are stretch receptors of arterial baroreceptors located?

Answer 5

in carotid sinuses and aortic arch

Question 6

What is the role of stretch receptors of arterial baroreceptors?

Answer 6

detect physical deformations in the vessel wall due to blood pressure changes

Question 7

What is the innervation of the carotid sinus baroreceptors?

Answer 7

the afferents travel the sinus nerve to the glossopharyngeal nerve to the NTS

Question 8

What is the innervation of the aortic arch baroreceptors?

Answer 8

afferents travel along the vagus nerve to the NTS

Question 9

How does the firing rate change between systole and diastole?

Answer 9

decreases during late systole and diastole

Question 10

How does baroreceptor stimulation affect sympathetic and parasympathetic activity?

Answer 10

• decreases sympathetic
• increases parasympathetic

Question 11

What does an increased baroreceptor firing rate lead to?

Answer 11

vasodilation and bradycardia

Question 12

What is the sympathetic pathway in baroreceptor stimulation?

Answer 12

increased BP -> increased baroreceptor firing -> decreased sympathetic discharge -> decrease vasoconstriction -> decrease BP

negative feedback occurs once at the bottom and goes back to the top

Question 13

What is the parasympathetic pathway in baroreceptor stimulation?

Answer 13

increased BP -> increased baroreceptor firing -> increased vagal discharge -> decrease heart rate -> decrease BP

Question 14

How do arterial baroreceptors adapt?

Answer 14

occurs during long-term changes in mean arterial BP, having a decreased sensitivity to pressure changes

Question 15

In low pressure baroreceptors, where are mechanoreceptors located?

Answer 15

atria and pulmonary vessels

Question 16

What do afferent neurons run to the medulla?

Answer 16

the vagus

Question 17

Increased stimulation has what affect on medullary centers?

Answer 17

increases stimulation of centers

Question 18

An increase in stimulation of the medullary centers causes what?

Answer 18

• decreased parasympathetic output to the heart (increase HR)
• increased sympathetic output to the heart (increase HR)

Question 19

What are the 2 types of chemoreceptors?

Answer 19

central and peripheral

Question 20

What are the peripheral chemoreceptors organized into?

Answer 20

aortic and carotid bodies

Question 21

What are aortic and carotid bodies?

Answer 21

highly vascularized cells in aortic arch and carotid sinus that are sensitive to blood, O2, CO2, and pH

Question 22

What are aortic and carotid bodies involved in?

Answer 22

respiratory regulation

Question 23

What do central chemoreceptors have a primary role in?

Answer 23

respiratory regulation

Question 24

What does increased blood CO2 cause?

Answer 24

• stimulate central chemoreceptors
• causes increase in sympathetic outflow and vasoconstriction

Question 25

What does increased ventillation cause?

Answer 25

* decreases blood CO2 levels * results in vasodilation * reduces stimulation of central chemoreceptors

Question 26

What are hte mechanisms involved in long term blood pressure regulation?

Answer 26

* pituitary antidiuretic hormone * secretion * renin-angiotensin-aldosterone system * atrial natriuretic peptides

Question 27

What does long term control of blood pressure involve?

Answer 27

regulating systemic blood volume by the kidneys

Question 28

What is the mm Hg of a hypertensive individual?

Answer 28

* mean arterial blood pressure: >100 mm Hg * diastolic pressure: >90 mm Hg * systolic pressure: >135 mm Hg

Question 29

What is the mm Hg of a severe individual?

Answer 29

* mean arterial blood pressure: 150-170mm Hg * diastolic pressure: up to 130 mm Hg * systolic pressure: up 250 mm Hg

Question 30

In essential hypertension, how much is the mean blood pressure increased?

Answer 30

40-60%

Question 31

In essential hypertension, how much is TPR increased?

Answer 31

40-60%

Question 32

In essential hypertension, how much is renal resistance increased?

Answer 32

2-4 times

Question 33

What is the response to standing?

Answer 33

* pooling of blood in veins> decrease arterial pressure> increase sympathetic outflow

Question 34

When standing, what does an increase in sympathetic outflow cause?

Answer 34

* increase in heart rate, contractility, cardiac output * increase in TPR * decrease in unstressed volume