Physiological reflexes

Question 1

Baroreceptor reflex

Answer 1

Rise in BP detected by aortic arch and carotid sinus(pressure receptors), reset through the sympathetic/parasympathetic nervous system. Carotid strech causes decreased bp by supressing sympathetic action and increasing parasympathetic stimulation.

Question 2

Traub-hering waves

Answer 2

Fluctuations in BP, drifts with respiration.
Inspire, bp drops, expire,bp rises.
Baroreceptor reflex should counter this but is not enough alone.

Question 3

Bainbridge reflex

Answer 3

Receptors in the large veins and atria
Sensitive to blood volume
Stimulation of these stimulates HR
Ie increased blood volume increases HR.
Aim is to reduce damming of blood in the atria and veins, to avoid overloading the lungs with blood.

Question 4

Bocking carotid arteries (chin to chest)

Answer 4

Lack of blood to brain causes large rise in Bp

Question 5

Adr

Answer 5

Increases bp initially, fall in bp later due to b stimulation
Small release small increase
Large release large increase

Question 6

NA

Answer 6

Increases bp and decreases hr

Size of response depends on size of release.

Question 7

Vagal stimulation

Answer 7

Decreases HR

Question 8

Splanchnic nerves of cat

Answer 8

Increases bp as cats release NA from adrenals (splanchnic nerves innervate adrenals)

Question 9

Tarparnardes

Answer 9

Fluid injection into the pericardium results in increased pressure on the heart causing a drop in BP and decreased heartrate. Cutting the pericardium to release fluid causes HR and BP to return to normal.