Cardiac Autonomic Reflexes

Question 1

What are the 4 sensors?

Answer 1

Pressure
Muscle work
Chemoreceptors
Stretch receptors

Question 2

What do arterial baroreceptors provide info to?

Answer 2

NTS

Question 3

What does arterial baroreceptor activation cause?

Answer 3

Increases cardiac vagal activity
Decreases sympathetic activity to heart and vasculature
Contributes to baroreflex

Question 4

What is the Valsalva maneuver?

Answer 4

Forced expiration against a closed glottis which triggers changes in HR

Question 5

What are low pressure receptors?

Answer 5

Myelinated veno-atrial mechanoreceptors

Question 6

Where are low pressure receptors located?

Answer 6

Left and right atria

Question 7

What do low pressure receptors sense?

Answer 7

Changes in central venous pressure and cardiac distension

Question 8

What does low pressure receptor activation lead to?

Answer 8

Sympathetic-mediated increase in heart rate and diuresis
Bainbridge reflex

Question 9

What are the two types of muscle work receptors?

Answer 9

Mechanoreceptors
Metaboreceptors

Question 10

What do muscle work receptors contribute to?

Answer 10

Exercise-associated increases in heart rate and blood pressure

Question 11

What do muscle mechanoreceptors cause?

Answer 11

Rapid increase in HR by reflex inhibition of cardiac vagal tone

Question 12

What do muscle metaboreceptors cause?

Answer 12

Increase cardiac contractility and vascular tone by reflex activation of sympathetic activity

Question 13

What activates lung stretch receptors?

Answer 13

Inspiration triggers a reflex tachycardia

Question 14

What causes tachycardia?

Answer 14

cardiac vagal parasympathetic inhibition mediated by the lung stretch receptor afferent fibers and inspiratory neurons

Question 15

What reverses the influence of inspiratory neurons?

Answer 15

Expiration - respiratory sinus arrhythmia

Question 16

Where are arterial chemoreceptors located?

Answer 16

carotid bodies and aortic bodies that monitor blood gas levels

Question 17

What are arterial chemoreceptors stimulated by?

Answer 17

Low O2 levels
High CO2 levels
Acidosis

Question 18

What do arterial chemoreceptors account for?

Answer 18

Circulatory reflexes associated with asphyxia and obstructive sleep apnoea

Question 19

What do afferent fibers run alongside?

Answer 19

Baroreceptor afferents

Question 20

What does somatic pain cause?

Answer 20

Tachycardia
Hypertension

Question 21

What does visceral pain cause?

Answer 21

Bradycardia
Hypotension

Question 22

What do the special senses cause?

Answer 22

Tachycardia

Question 23

What does cold water cause?

Answer 23

Bradycardia

Question 24

What triggers vasovagal syncope (VVS)?

Answer 24

Sudden emotional stress

Question 25

What are 4 features of VVS?

Answer 25

Increased vagal output of the heart
Reduced peripheral sympathetic activity
Bradycardia
Reduction in peripheral resistance