Control of Arterial Pressure - short term

Question 1

What are baroreceptors?

Answer 1

Sensory nerve fibre endings that detect changes in pressure

Question 2

Where are arterial baroreceptors located?

Answer 2

Adventitia layer of:
Aortic arch
Carotid sinuses

Question 3

Where are cardiopulmonary mechanoreceptors located?

Answer 3

Cardiac chambers
Veno-atrial regions
pulmonary arteries

Question 4

What structure do baroreceptors provide information for?

Answer 4

Nucleus tractus solitarius (NTS) in medulla oblongata

Question 5

What are two nerve pathways baroreceptors use?

Answer 5

1. carotid sinus baroreceptors via carotid sinus and glossopharyngeal nerves
2. Aortic arch baroreceptors via aortic and vagus nerves

Question 6

What is the baroreflex?

Answer 6

Pressure buffer system
Negative feedback system

Question 7

Baroreceptors differ to:

Answer 7

Threshold
Range
Action potential frequency
Sensitivity

Question 8

What happens if MAP decreses?

Answer 8

Baroreceptor action potential frequency decreases

Question 9

What controls the baroreflex?

Answer 9

Sympathetic nervous system
Parasympathetic nervous system

Question 10

What is orthostatic hypotension?

Answer 10

Movement to upright posture

Question 11

What three baroreflex triggers reduce MAP?

Answer 11

Supine to upright
Haemorrhage
Decrease in carotid sinus pressure

Question 12

What increases sympathetic nerve activity in the medulla?

Answer 12

Inhibition of Rostral ventrolateral medulla (RVLM)

Question 13

What inhibits vagal parasympathetic nerve activity?

Answer 13

Positive feedback of nucleus ambiguus and dorsal vagal motor nucleus

Question 14

What is the Carotid Sinus Pressure?

Answer 14

Difference between diastolic and systolic pressure

Question 15

What does the carotid sinus pressure depend on?

Answer 15

Depends on stroke volume and elasticity

Question 16

What does the acute firing of the sinus nerve cause?

Answer 16

Reflex fall
Decrease in MAP

Question 17

What 3 receptors affect the medulla?

Answer 17

Mechanoreceptors
Chemoreceptors
Muscle work receptors

Question 18

What two neurotransmitters influence arterial pressure?

Answer 18

Noradrenaline
Adrenaline

Question 19

What influence are noradrenaline and adrenaline under?

Answer 19

Sympathetic nervous system

Question 20

What effect does noradrenaline have on TPR?

Answer 20

Increases TPR via alpha adrenoceptors

Question 21

How does noradrenaline increase cardiac output?

Answer 21

By increasing stroke volume and heart rate via cardiac beta 1 adrenoreceptors

Question 22

What is noradrenaline’s effect on blood pressure?

Answer 22

Raises blood pressure which triggers a baroreflex to reduce heart rate

Question 23

What receptor does noradrenaline have a greater affinity for?

Answer 23

alpha receptors

Question 24

What is adrenaline’s effect on TPR?

Answer 24

Decreases TPR via beta 2 adrenoreceptors

Question 25

How does adrenaline increase cardiac output?

Answer 25

By increasing stroke volume and heart rate via cardiac beta 1 adrenoreceptors

Question 26

What effect does adrenaline infusion have on blood pressure?

Answer 26

Little effect on blood pressure -> no baroreflex-mediated reduction

Question 27

What does the flight or fight response allow?

Answer 27

Allows for blood to be recruited to muscle

Question 28

How is TPR reduced?

Answer 28

Diminished stimulation of vascular smooth muscle cell alpha-adrenoreceptors as SNS activity is reduced