Cardiovascular Receptors

Question 1

What are the 4 types of receptors, what do they sense and are they excitatory or inhibitory of the SNS when active

Answer 1

cardiopulmoary baroreceptors (sense changes in LV pressure) - inhibitory

arterial baroreceptors (sense canges in BP) - inhibitory

aterial chemoreceptors (snese changes in arterial O2 and CO2) - excitatory

muscle metaboreceptors (sense changes in chemical milieu of muscles) - excitatory

Question 2

Arterial Baroreceptors

Answer 2

nerve endings on aortic arch and carotid sinus

cranial nerves 9 and 10

if BP decreases, ABR decreases to stop inhibiting SNS, thus increase HR, contractility and SV

increases efferent SNS to kidney (vasoconstriction and RAAS activation), efferent SNS to skeletal muscle (vasoconstriction), efferent SNS to splanchinic circulation (vasoconstrtion to gut)

restores BP

buffer ACUTE changes in BP

Question 3

what would happen to BP if you cut the ABR?

Answer 3

mean BP not changes, but fluctuations around the mean increase

Question 4

Cardiopulmonary Baroreceptors

Answer 4

3 classes - know unmyelinated mechanoreceptors in atria and LV, travel on nerve X

sense changes from LVEDP and contractility

stand and LVEDV drops, decrease nerve firings and stimulate SNS

Question 5

What would happen to BP if you cut BOTH ABR and cardiopulmonary baroreceptors?

Answer 5

mean BP and fluctations increase because cardiopulmonary baroreceptors are most important regulators of renal blood flow and volume regulation

Question 6

Arterial Chemoreceptors

Answer 6

in carotid and aortic bodies, nerves 9 and 10

sense chemical changes lke hypoxemia, hypercapnia and acidosis

asphyxia - increase firing

increases vagal in Heart so HR slows

increase SNS is kidneys, skeletal muscle and splanchnic nerve and increase respiratory system (increase tidal volume activates pulmonary stretch receptors and get lung inflation reflex with causes increase HR)

the lung inflation reflex will win over the vagal by baroreceptors

Question 7

Dive Reflex

Answer 7

cold water touches face

vagal activity increases

arterial chemoreceptors activated

able to tolerate asphyxia longer and to terminate SVT

Question 8

Muscle Metaboreceptors

Answer 8

info relayed is spinal column

sense ischemic metabolites, sensitive to under perfusion of working muscle

increases SNS in heart, kidney, muscle, gut

Question 9

How do muscle metaboreceptors work in exerice?

Answer 9

ischemic metabolites made and muscle metaboreceptors activated

increase HR and contractility, renal vasoconstriction and activate RAAS, vasoconstriction in smucles and in gut

maintain BP and direct blood flwo to working muscle

Question 10

Why doesn’t working muscle become more ischemic if SNS increases to working muscle?