Autonomic nervous system

Question 1

what are the anatomical divisions of the brain stem and spinal cord

Answer 1

medullary 
cranial
thoracic
lumbar
sacral

Question 2

what anatomical divisions are part of the sympathetic

Answer 2

thoracic

lumber

Question 3

which anatomical divisions are parasympathetic

Answer 3

medullary

sacral

Question 4

parasympathetic nerves

Answer 4

• originate in the lateral horn of the medulla and sacral spinal cord
• have long myelinated preganglionic fibres
• short postganglionic unmyelinated fibres
• ganglia are located within the innervated tissues
• have action sthat oppose the sympathic nervous system

Question 5

sympathetic nerves

Answer 5

• originate in the lateral horn of lumbar and thoracic
• have short myelinated preganglionic fibres
• have long unmyelinated postganglionic fibres
• ganglia are located in the paraventerbral chain close to the spinal cord

Question 6

What neurotransmitter do all pre-ganglionic neurons use?

Answer 6

they are cholinergic- Acetylcholine

Question 7

what neurotransmitter do parasympathetic post-ganglionic neurons use?

Answer 7

cholinergic
ACh
muscarinic ACh receptors in the target effector tissue

Question 8

what type of neurons are most of the post-ganglionic sympathetic nerves?

Answer 8

most are noradrenergic

-they use noradrenaline

Question 9

what major class of adrenoceptors does Noradrenaline use

Answer 9

alpha-adrenoceptors and beta-adrenoceptors

Question 10

which sympatheic post-ganglionic neurons are cholinergic not adrenergic

Answer 10

• those innervating sweat glands, hair follicles- piloerection
• they release ACh that acts at muscarinic ACh receptors

Question 11

sympathetic postganglionic neurons in adrenal glands

Answer 11

• are differentiated to form neurosecretory chromaffin cells
• chromaffin cells can be considered as postganglionic sympathetic neurons that do not project to a larger tissue
• instead, on sympathetic stimulation these cells release adrenaline into the bloodstream

Question 12

What does parasympathetic release of ACh at M2 cause?

where are M2 adrenoceptors?

Answer 12

M2

• bradycardia
• reduced cardiac conduction velocity

heart

Question 13

what are the most common sites for drug intervention in neurotransmission?

Answer 13

• degradation of neurotransmitter
• interaction with post-synaptic receptors
• inactivation of transmitter
• re-uptake of transmitter
• interaction with pre-synaptic receptors

Question 14

what enzyme breaks down acetylcholine

Answer 14

acetylcholinestase

AChE

Question 15

what enzyme makes acetylcholine

Answer 15

choline acetyltransferase

Question 16

what are the consequences of lack of selectivity of cholinergic drugs - muscarinic ACh receptor agonist

Answer 16

heart:
decreased heart rate and cardiac output

smooth muscle:
increased bronchoconstriction
increased GI peristalsis

exocrine:
increased sweating and salivation

Question 17

what is SLUDGE syndrome

Answer 17

the pathological effects indicative of massive discharge of the parasympathetic nervous system

Salivation
Lacrimation
Urination
Defecation
Gastrointestinal upset
Emesis

Question 18

what causes SLUDGE syndrome

Answer 18

drug overdose
ingestion of magic mushrooms
exposure to organophosphorus insecticides
exposure to nerve agents

prolonged over stimulation of muscarinic acetylcholine receptors

Question 19

termination of noradrenergic transmission

Answer 19

reuptake into the pre-synaptic terminal by a Na+-dependant, high affinity transporter

if not taken up by reuptake it is taken up by a lower affinity, non-neuronal mechanism

Question 20

what is the fate of NA not taken up into vesicles

Answer 20

it is susceptible to metabolism by 2 enxymes

• monoamine oxidase
• catechol-O-methyltransferase

Question 21

what opposes bronchoconstriction in asthma

Answer 21

beta-2 adrenoreceptor-selective-agonists- salbutamol

Question 22

basic steps in neurotransmission that can be common sites of drug action

Answer 22

4. degradation of transmitter
5. interaction with post-synaptic receptors
6. inactivation of transmitter
7. re-uptake of transmitter
8. interaction with pre-synaptic receptors

Question 23

basic steps of neurotransmission

Answer 23

1. uptake of precursors
2. synthesis of transmitter (T)
3. vesicular storage of transmitter
4. degradation of transmitter
5. depolarisation by propagated action potential
6. influx of Ca2+ in response to depolarisation
7. exocytotic release of transmitter
8. diffusion to post-synaptic membrane
9. interaction with post-synaptic receptors
10. inactivation of transmitter
11. re-uptake of transmitter or degradation product(s)
12. interaction with pre-synaptic membrane

Question 24

What does parasympathetic release of ACh at M3 cause?

where are M3 adrenoceptors?

Answer 24

M3

• bronchial contraction
• increased intestinal mobility/secretion
• bladder contraction and relaxation
• penile erection
• cillary muscle and iris sphincter contraction

smooth muscle

Question 25

What does parasympathetic release of ACh at M1/ M3 cause?

where are M1/M3 adrenoceptors?

Answer 25

M1/M3
-increased sweat/salivary/lacrimal secretion

glandular

Question 26

What does sympathetic release of noradrenaline cause at the b1? and where are b1 receptors

Answer 26

beta 1

• tachycardia
• positive inotropy and chronotropy

heart

Question 27

what does sympathetic release of noradrenaline do on smooth muscle?

Answer 27

arteriolar contraction/ venous contraction- a1 b2

bronchiolar/intestinal/uterine relaxation b2

Question 28

how do you treat sludge

Answer 28

treated with atropine, pralidoxine