The Autonomic Nervous System

Question 1

function of the ANS

Answer 1

Maintains the internal environment of the body, operating at a subconscious level.

acts as a drug target

involuntary NS

Question 2

why does the ANS act as a major drug target?

Answer 2

as it exerts control over the organs

Question 3

what type of muscle does the ANS contain?

Answer 3

smooth and cardiac

Question 4

what is the ANS made up of?

Answer 4

sympathetic
parasympathetic
enteric

(NS)

Question 5

role of sympathetic ns

Answer 5

fight or flight

Question 6

role of parasympathetic ns

Answer 6

rest and digest

Question 7

role of enteric ns

Answer 7

gut

Question 8

similarity of the sympathetic and parathetic NS - are they both active at the same time?

Answer 8

These are the extremes with opposing effects – both systems are constantly active with most organs innervated by both. (all motor neurons)

Question 9

what NT does the sympathetic NS use?

Answer 9

The sympathetic NS utilises noradrenaline and acetylcholine:

Question 10

which NS uses noradrenaline and acetylcholine?

Answer 10

sympathetic

Question 11

describe the preganglionic neuron in the sympathetic NS

Answer 11

preganglionic neuron is cholinergic which means it releases acetylcholine.

Question 12

what does cholinergic mean

Answer 12

releases acetylcholine

Question 13

what receptors are on the postganglionic neurons of both the sympathetic and parasympathetic NS?

Answer 13

nicotinic acetylcholine receptors

Question 14

where can one find nicotinic acetylcholine receptors?

Answer 14

what receptors are on the postganglionic neurons of both the sympathetic and parasympathetic NS

Question 15

how are nicotinic acetylcholine receptors activated?

Answer 15

by nicotine

Question 16

describe the postganglionic neuron in the sympathetic NS

Answer 16

postganglionic neuron is adrenergic and therefore releases noradrenaline

Question 17

what does adrenergic mean

Answer 17

releases noradrenaline

Question 18

which neuron is adrenergic and which is cholinergic in the sympathetic NS?

Answer 18

preganglionic is cholinergic and postganglionic is adrenergic

Question 19

where are the preganglionic neurons of the sympathetic system found?

Answer 19

between T1 down to L2

Question 20

what is found between T1 to L2?

Answer 20

the preganglionic neurons of the sympathetic system

Question 21

describe the basic concepts of the wiring in the ANS

Answer 21

preganglionic neuron (myelinated) runs from the spinal cord and synapses with the ganglion. information is transmitted to the effector by the postganglionic neuron (unmyelinated)

Question 22

in the sympathetic NS, which neuron is myelinated and which is unmyelinated?

Answer 22

preganglionic is myelinated and postganglionic is unmyelinated.

Question 23

what receptor is on the effector in the sympathetic NS?

Answer 23

adrenergic

Question 24

what NT does the parasympathetic NS use?

Answer 24

only uses acetylcholine but with 2 different receptor types

Question 25

describe the preganglionic and postganglionic neurons in the parasympathetic NS

Answer 25

both neurons are cholinergic and therefore, release acetylcholine

Question 26

what receptors are on the effectors in the parasympathetic NS?

Answer 26

muscarinic receptors

Question 27

which NS has muscarinic receptors?

Answer 27

parasympathetic

Question 28

which NS has adrenergic receptors?

Answer 28

sympathetic

Question 29

which NS has nicotinic receptors?

Answer 29

both

Question 30

what are muscarinic receptors stimulated by?

Answer 30

pilocarpine

Question 31

where are the preganglionic neurons of the parasympathetic NS?

Answer 31

cells top and tail T1-L2 (sympathetic region)

arise from cranial nerve III (oculomotor), cranial nerve X (Vagus), and sacral segments (S2-S4)

Question 32

role of vagus nerve in parasympathetic NS

Answer 32

contributes to the parasympathetic innervation of abdominal and thoracic viscera (sympathetic innervation of the viscera is carried out via the splanchnic nerves)

Question 33

what in the ANS act as drug targets?

Answer 33

pre and post-synaptic receptors

synthesising enzymes

transporters

degrading enzymes

Question 34

2 major subtypes of adrenergic receptors (and their subforms)

Answer 34

alpha (1 and 2) and beta (1, 2 and 3)

Question 35

what is an agonist of alpha 2?

Answer 35

clonidine

Question 36

clonidine is an agonist of what receptor?

Answer 36

alpha 2

Question 37

describe adrenergic receptors

Answer 37

2 major subtypes (alpha and beta)

metabotropic, G-protein linked receptors (not ion channels)

tissue-specific distribution

Question 38

explain the benefit of tissue-specific distribution of adrenergic receptors

Answer 38

o Excellent pharmacological targets (particular organ/tissue will have particular receptor type)

Question 39

what do beta receptors do?

Answer 39

 Bind noradrenaline in parasympathetic NS

Question 40

beta receptors - agonists example

Answer 40

(e.g. salbutamol - 𝛽2 agonist – asthma treatment)

Question 41

beta receptors - antagonists example

Answer 41

(e.g. propranolol – reduces HR, BP and contractile force – not beta specific)

Question 42

where do sympathetic postganglionic neurons innervating the structures of the face arise?

Answer 42

from the superior cervical ganglion

Question 43

where do parasympathetic postganglionic neurons innvervating the lacrimal gland arise?

Answer 43

from the pterygopalatine ganglion

Question 44

difference of the adrenal medulla in the context of ganglionic neurons

Answer 44

adrenal medulla is directly innervated by preganglionic neurons
o It is essentially the ganglion

Question 45

what is referred pain?

Answer 45

pain felt at a site that is not injured itself but due to the sensory innervation for that site entering the spinal cord at the same level as the sensory innervation for an injured site.

Question 46

orthostatic hypotension

Answer 46

o More prevelent in the elderly
o Side effect of drugs that block the 𝛼1 adrenergic receptor
o Is a drop in BP caused by the ANS not reacting quickly enough when standing up.