Autonomic nervous system

Question 1

pre-ganglionic nerve cell bodies are located in the ____

Answer 1

CNS - Brainstem or spinal cord

Question 2

Post-ganglionic nerve cell bodies are located in _____

Answer 2

Ganglia

Question 3

Are Autonomic, post-ganglionic nerves myelinated or not?

Answer 3

Usually not

Question 4

Compared to the sympathetic NS, the parasympathetic preganglion fibres are ____ and the postganglionic fibres are ___

Answer 4

Parasympathetic has Long preganglionic fibres and Short postganglionic fibres becuase the ganglia are located near the target organs.

Question 5

How do the SNS and the PNS differ in the way they act at their various target organs?

Answer 5

The SNS usually acts as a functional unit - discharging at multiple effector organs and releasing epinephrine from the adrenal gland simultaneously. The PNS, in contrast, acts discretely at different sites at different times - it is not activated as a complete system

Question 6

Are the SNS and the PNS required for life?

Answer 6

SNS - no. PNS - yes

Question 7

What are the three integrating centres of the ANS?

Answer 7

The hypothalamus, the medulla and the spinal cord.

Question 8

Which systems are innervated only by the SNS

Answer 8

Adrenal Medulla
Kidneys
Pilomotor muscles
sweat glands
Blood pressure control

Question 9

The 3 types of chemical signalling between cells…

Answer 9

Local Mediators e.g histamine, prostaglandins
Hormones
Neurotransmitters

Question 10

Preganglionic neurones use ___ as their neurotransmitter on postganglionic cells. The receptors on the postganglionic cells and in the adrenal medulla are ____

Answer 10

Acetylcholine, Nicotinic

Question 11

Postganglionic neurones use ____ and ____ as their neurotransmitters and these act on ____ and _____ receptors.

Answer 11

SNS - noradrenaline, adrenergic, ANS - acetylcholine, muscarinic

Question 12

3 mechanisms for receptor - effector coupling

Answer 12

1. Receptors/ion channels/change in membrane potential or intracellular ion concentrations
2. Receptor/Gs protein/adenylyl cyclase/protein phosphorylation
3. Receptor/Gq/Phospholipase C/Diacylglycerol, Inositol Triphosphate/Protein phosphorylation and increased intracellular Ca2+

Question 13

Acetylcholine is formed by the reaction of ______ with ______, and is catalysed by ______

Answer 13

Choline and Acetyl coA, catalysed by Choline acetyltransferase

Question 14

botulinum toxin causes ——

Answer 14

Prevents release of ACh at synapses

Question 15

Black widow spider venom causes —-

Answer 15

Complete empyting of all presynaptic ACh vesicles into the synapse.

Question 16

ACh is degraded in the synapse by….

Answer 16

Acetylcholinesterase

Question 17

The stimulus for release of neurotransmitter vesicles into the synapse is….

Answer 17

Rise in intracellular calcium from opening of voltage gated Ca2+ channels

Question 18

Carbachol

Answer 18

Muscarinic and nicotinic agonist. High potency and long duration of action. Used locally in the eye - causes accommodation and miosis - useful in glaucoma to reduce IOP

Question 19

Pilocarpine

Answer 19

Muscarinic activity. Used in opthalmology. Causes miosis and ciliary muscle contraction. Used for emergency lowering of IOP in glaucoma by allowing increased draining of the aqueous humor.

Question 20

Physostigmine and Neostigmine.

Answer 20

anticholinesterase - binds to and inactivates the acetylcholinesterase that breaks down ACh in the synaptic cleft. Can be used in myaesthenia Gravis

Question 21

Pyridostigmine, ambenomium, edrophonium

Answer 21

anticholinesterases - can be used in the treatment and diagnosis of myasthenia gravis.

Question 22

Tarcine, donezepil, ricastigmine and gelantamine

Answer 22

aticholinesterases used to slow the progression of alzheimers. These patients have a deficiency of cholinergic neurons in the CNS.