L9 - Autonomoc Control Of CVS

Question 1

Which system has thoracolumbar origins and which system has craniosacral origins

Answer 1

Thoracolumbar - sympathetic

Craniosacral - parasympathetic

Question 2

Which NT is the predominant one in

a) pre-ganglionic fibres
b) post ganglion SYM
c) post-ganglionic PARA

Answer 2

a) Ach - nicotine’s receptors
b) NA - adrenoceptors
c) Ach - muscarinic receptors

Question 3

What effect does B1 adrenceptor activation have on the heart?

Answer 3

Increases force and rate of contraction (also vasoconstriction) this is important because CO is affected by peripheral resistance

Question 4

Describe some major effects of dominant sympathetic activity

Answer 4

Bronchodilaton 
Vasoconstriction 
Dilated pupils 
Decrease GI activity
Increase HR

Question 5

Will a denervated heart have a higher or lower HR than a denervated one any why

Answer 5

Higher
explanation - hearts have intrinsic activity from the pacemakers, at rest this is modulated down by parasympathetic vagal input

Question 6

What two effects come from M2 receptor activation?

Answer 6

Decreased HR and Av Nnode conduction velocity

Question 7

What effects does activation of B1 receptors have on the heart?

Answer 7

Increased heart rate and force of contraction (positive chronotropic and inotropic effects)

Question 8

What nerve do the efferents emerging from the
a) carotid sinus baroreceptors
b) aortic arch baroreceptors
travel in?

Answer 8

a) vagus

b) vagus

Question 9

At what level do the nerves from the baroceptors synapse in the brain stem with the cardiovascular control centre?

Answer 9

Medulla oblongata

Question 10

What are the effects of baroceptors activated by increased blood pressure on the heart?

Answer 10

Decreased sympathetic activity - decreased rate and force of contraction

Question 11

What effect does
a) sympathetic activation via B1 receptor
b) para activation via m2 receptor
Have on the gradient of the pacemaker potential?

Answer 11

a) increase
b) decrease

Thus affecting HR

Question 12

Some blood vessels have alpha 1 and b2 adrenoceptors on, does circulating adrenaline have a higher affinity for a1 or b2?

Answer 12

B2

Question 13

At high concentrations of adrenaline it will act on a1 and b2 receptors on blood vessels. But preferentially it will cause vasoconstriction by binding a1. What is adrenaline then used for treating?

Answer 13

Anaphylaxis

Question 14

Sympathomimetics mimic endogenous sympathetic agonists, give a use for adrenaline other than anaphylaxis and explain what dobutamine is and what it’s used for

Answer 14

Adrenaline can be used to restore function in cardiac arrest

Dobutamine is a B1 agonist and can be given in cardiogenic shock(pump failure)

Question 15

Prazosin is an adrenoceptors antagonist it causes vasodilation. Suggest a use

Answer 15

Anti-hypertensive agent

Question 16

Propanolol is. Non selective b antagonist, it can be used to reduce heart rate, what problem can arise from it though

Answer 16

Slows heart rate (B1) but also acts on bronchial muscle (b2) to cause bronchoconstriction

Question 17

Atenolol is a b_ selective antagonist

Answer 17

1

Question 18

Give a use for

a) pilocarpine, a muscarinic agonist
b) atropine, a muscarinic antagonist

Answer 18

a) glaucoma - activates constrictor muscles in eye

b) increase HR/dilate pupils in eye examination

Question 19

look at table in lecture telling you all the individual receptors actions

Answer 19

t

Question 20

What are the effects of the following:

a) alpha 1 activation
b) alpha 2 activation
c) beta 1 activation
d) beta 2 actvation
e) M2 activation
f) M3 activation

Answer 20

a1 = vasconstriction
A2 = vasodilation 
b1 = increase HR and force of contration
b2 = bronchodilation 

M2 = decrease HR 
M3 = bronchoconstriction