The Autonomic Nervous System And The CVS

Question 1

What is the general organisation of the two different autonomic nervous systems?

Answer 1

There are two neurones arranged in series,
the on that originates in the central is the pre ganglionic neurone
The one that originates in the peripheral nervous system in the post ganglionic neurone where they both target n effector cell.

Question 2

How is the sympathetic division of the nervous system organised?

Answer 2

Pregangloic neurones arise from segments T1 to L2 (thoracolumbar origin).
Most syncope with the postgangolic neurones in the paravertebral chains of the ganglia.

Question 3

How is the parasympathetic division of the autonomic nervous system organised?

Answer 3

Craniosacral origin
Synapse in neurones with ganglia close to the target tissue.
Short post ganglionic fibres.
Pregangloic fibres travel in cranial nerves or the cranial outflow tract.

Question 4

What is the neurotransmitter released in preganglonic neurones of the parasympathetic nervous system.

Answer 4

Actelycholine (acts on nictonic receptors)

Question 5

What is the neurotransmitter released in the postganloic neurones of the paracympatheic nervous system?

Answer 5

Acteylcholine (acting on Muscarinic, g protein coupled, receptors)

Question 6

What is the neurotransmitter released by the postgangolic neurones of the sympathetic nervous system?

Answer 6

Noradrenaline

Question 7

What are the different subtypes of Adrenoreceptors?

Answer 7

B- Adrenoreceptors (B1 and B2), and a-adrenoreceptors, a1 and a2

Question 8

Why is sympathetic control to different tissues independently regulated?

Answer 8

Allows, for example, sympathetic activity of heart to be increased without increasing sympathetic activity of the GI tract, and there is potential for coordinated response such as fight of flight.

Question 9

Describe how the sympatheic nervous system effects the pupil of the eye?

Answer 9

Dilatation, by contracting the radial muscles and acting on A1 receptors.

Question 10

How does the parasymptheic nervous system effect the pupil of the eye?

Answer 10

Contracts the pupil by causing contraction of the spinchter muscle, acting on the M2 Muscarinic receptors.

Question 11

What does the ANS effect in the heart?

Answer 11

The heart rate, force of contraction of heart and the peripheral resistance of the blood vessels.

Question 12

What does the ANS not control in the heart?

Answer 12

Does not initiate electrical activity, without nervous control the heart continues to beat but at a faster rate.

Question 13

What nerve controls the Parasympathetic input to the heart?

Answer 13

Preganloic fibres include the 10th cranial nerve, also known as the vagus.

Question 14

Where do Parasympatheic fibres act on the heart?

Answer 14

They synapse on the epicardial surface on within the heart at the AV and the SA node

Question 15

What receptros are involved in the parasympathetic response of the heart and what response do they create?

Answer 15

The M2 receptors for ACh, decreasing the heart rate and having a negative chronotrophic response.

Question 16

What nerves are involved in the sympathetic response of the heart?

Answer 16

The postgangloinic fibres from the sympathetic trunk.

Question 17

What receptors does noradrenaline act on in the sympathetic response of the heart?

Answer 17

mainly on the b1 Adrenoreceptors, which increases the heart rate by a positive chronotrophic effect.

Question 18

What effect would having autonomic nervous system activity have on the SA node action potential graph?

Answer 18

Sympathetic activity would increase the slope of the pacemaker potential, parasympathetic activity would decrease the slope of the pacemaker potential.

Question 19

How is the parasympathetic effect on the pacemaker potential mediated?

Answer 19

M2 recpetors, that are g protein coupled, increase the K+ conductance, and decrease cAMP.

Question 20

How is the sympathetic effect on the pacemaker potential mediated?

Answer 20

Mediated by B1 receptors, G protein coupled receptors, increase cAMP which speeds up the pacemaker potential.

Question 21

What is the mechanism by which noradrenaline increases the force of contraction of the heart?

Answer 21

NA acts on B1 receptors in the myocardium, cause an increase in cAMP, activates PKA, and causes phosphorylation of the Ca2+ channels which increases the Ca2+ entry during the action potential. It also increases the Ca2+ concentration in the sacroplasmic reticulum.

Question 22

What sort of innervation do the blood vessels have?

Answer 22

Sympatheic innervation only.

Question 23

What sort of receptors do aterties and veins have?

Answer 23

A1 Adrenoreceptors

Question 24

What are three types of drugs that act on the autonomic nervous system?

Answer 24

Sypathomelcis, adrenoreceptor Agnoists, cholingerics.

Question 25

What are some of the cardiovascular uses of sympathemlics?

Answer 25

Administration of ardelinaine during a cardiac arrest, adrenaline in a anapthlic shock, B1 agnoists are given in cariogenic shock, B2 Agnoists include subutamla for treting asthma.

Question 26

What are sympthamelics?

Answer 26

Adrenoreceptor Agnoists

Question 27

What can you use a adrenreeptor anatgnoists for?

Answer 27

Anti hypertensive agent, and to inhibit Na action on vascular smooth muscle.

Question 28

What would you use B receptor antagonists for?

Answer 28

Slows heart rate and the force of contraction

Question 29

What are the issues of using non selctive b1/B2 atnagnoists?

Answer 29

Can cause brochocontrictision.

Question 30

What would you use muscarnic Agnoists for?

Answer 30

Pilapine, used in the treatment of glaucoma.

Question 31

what would you use cholgineric muscarinic anatgnoists for?

Answer 31

Increasing the heart rate, used to dilate the pupils in certain treatments.

Question 32

What are the two divisions of the ANS?

Answer 32

Parasympatheic and Sympathetic