Autonomic Reflexes

Question 1

Cushing Triad

Answer 1

Increased ICP leads to SNS mediated increased in blood pressure, increase in vascular tone triggers bradycardia (baro receptor)

Question 2

Autonomic Dysreflexia

Answer 2

Chronic disruptions of spinal cord signaling
Area of disruption is above T5
Stimuli-bladder/bowel distension, or surgical stimulation trigger exaggerated SNS response

Question 3

Baroreceptor

Answer 3

Stretch receptors in carotid artery and aorta sense changes in BP, causes vagal response (bradycardia, hypotension) common with phenylepherine administration

Question 4

Chemoreceptor reflex

Answer 4

Central chemoreceptors are sensitive to changes in pH and arterial carbon dioxide, hypercarbia results in aggressive increase in minute ventilation

Question 5

Bainbridge reflex

Answer 5

Increase in CVP triggers stretch receptors- causes tachycardia

Question 6

Behold-Jarvisch reflex

Answer 6

Hypotension, bradycardia and peripheral vasodilation

Noxious stimuli in the ventricle-response to myocardial ischemia to increase blood flow to the myocardium and decrease the work of the heart

Question 7

Valsalva maneuver

Answer 7

Forced expiration against a closed glottis, Mx ANS mediated responses:
-increased intrathoracic pressure= decreased cardiac filling and blood pressure
-triggers baro receptor and tachycardia/increase in CO

Question 8

Oculo-cardiac reflex

Answer 8

Trigeminal nerve-stimulation causes parasympathetic response, notably severe bradycardia. Cessation of stimuli returns normal HR
Can be blocked via atropine, glyco, or a nerve block