Lecture 16 - Autonomic Control

Question 1

Atropine use?

Answer 1

muscarinic antagonist; injected after heart attack to reverse transient increase in parasympathetic tone - increases firing of SA and conduction of AV nodes

Question 2

Adrenoceptors and agonists?

Answer 2

alpha (NA) and beta (isoproteronol) - adrenaline middle effectiveness for both

Question 3

Adrenoceptor subtypes?

Answer 3

beta 1 (heart), beta 2 (S.M relax), alpha 1 (vascular S.M contract) and alpha 2 (inhibit transmitter)

Question 4

Adrenoceptor drugs?

Answer 4

a1 (phenylephrine), b2 (clonidine), b1 (dobutamine) and b2 agonists (salbutamol)

Question 5

Overall nervous control on CV system?

Answer 5

Parasymp: vagal control of heart; symp: heart rate, stroke volume, cardiac output and vascular tone

Question 6

Events causing change in HR?

Answer 6

Ach hyperpolarise/NA increase depol of membrane potential through ion channel alteration

Question 7

Neural control of stroke volume?

Answer 7

NA release increases cytosolic Ca due to - HR shortening extrusion time, increased Ca influx, increased release by SR

Question 8

Beta blocker function?

Answer 8

prevent arrhythmias, reduced work in heart failure, reduce blood pressure

Question 9

Difference between a1 recptor and beta recepors?

Answer 9

GPCR rather than PKA pathway

Question 10

Reflexes maintaining arterial pressure?

Answer 10

baroreceptor reflex, chemoreceptor reflex, CNS ischemic response