Function & Neurochemistry Of ANS

Question 1

What does the somatic nervous system act on?

Answer 1

Skeletal muscles

Question 2

What does the autonomic nervous system act on?

Answer 2

Cardiovascular system and other organs

Involuntary muscles

Question 3

What is the main function of the autonomic nervous system?

Answer 3

Maintain homeostasis

Question 4

What does the enteric nervous system do?

Answer 4

Controls digestive system

Question 5

Which division of the ANS has more widespread innervation?

Answer 5

Sympathetic

Question 6

What is the typical structure of a parasympathetic neuron pathway?

Answer 6

Long pre-ganglionic neuron

Synapse in ganglion

Short post-ganglionic neuron

Question 7

What is the typical structure of a sympathetic neuron pathway?

Answer 7

Short pre-ganglionic neuron

Synapse in ganglion (sympathetic chain)

Long post-ganglionic neuron

Question 8

What part of the nervous system innervates the adrenal medulla?

Answer 8

Sympathetic

Question 9

What type of receptor is present in autonomic ganglions?

Answer 9

Cholinergic nicotinic receptors

Question 10

What kind of receptor is found at the neuromuscular junction?

Answer 10

Cholinergic nicotinic

Question 11

What type of receptors are at parasympathetic neuroeffector junctions?

Answer 11

Cholinergic muscarinic

Question 12

What type of receptor is present at the adrenal medulla?

Answer 12

Cholinergic nicotinic

Question 13

What does the adrenal medulla secrete and to where?

Answer 13

Adrenaline

Noradrenaline

Into bloodstream

Question 14

What kind of receptors do noradrenaline bind to?

Answer 14

Adrenergic

Question 15

What are the two types of cholinergic receptors?

Answer 15

Muscarinic

Nicotinic

Question 16

What gives nicotinic receptors their name?

Answer 16

Able to bind nicotine

Question 17

What gives muscarinic receptors their name?

Answer 17

Able to bind muscarine

Question 18

What type of receptor are muscarinic receptors?

Answer 18

7TM GPCR

Question 19

How many subtypes of muscarinic receptors are there?

Answer 19

5

Question 20

What are M2 receptors often described as?

Answer 20

Cardiac

Question 21

What muscarinic subtype is “cardiac”?

Answer 21

M2

Question 22

What are M3 receptors often described as?

Answer 22

Smooth muscle/glandular

Question 23

Which muscarinic subtype is found on smooth muscle/glands?

Answer 23

M3

Question 24

What G-protein are M2 receptors coupled to?

Answer 24

Gi

Question 25

What molecular effect do M2 receptors have when activated?

Answer 25

Decrease cAMP

Question 26

What second messengers are produced when M3 receptors are activated?

Answer 26

IP3 and DAG

Question 27

What G-protein is coupled to M3 receptors?

Answer 27

Gq

Question 28

How many subunits make up a nicotinic receptor?

Answer 28

5

Question 29

What are the subunits of a nicotinic muscle receptor?

Answer 29

a1 x2 b1 g e

Question 30

What are the subunits of a nicotinic ANS ganglionic receptor?

Answer 30

2x a3 3x b4

Question 31

What nicotinic receptor subtype is found at muscles?

Answer 31

N1

Question 32

What nicotinic receptor subtype is found at ANS ganglions?

Answer 32

N2

Question 33

How many acetylcholine molecules are required to activate an N1 receptor? What do they bind to?

Answer 33

2 a1 subunits

Question 34

What are the molecular events following a1 adrenergic receptor activation?

Answer 34

Activate Gq which stimulates PLC Stimulate IP3 and DAG pathways Increase cellular calcium ion concentration and stimulation of PKC

Question 35

What do a2 receptors do when activated?

Answer 35

Activate Gi Inhibit adenylyl cyclase/decrease cAMP Decrease release of NA

Question 36

Where are a2 adrenoreceptors found?

Answer 36

Presynaptically | Sympathetic

Question 37

What molecular effect does activation of b adrenoreceptors have?

Answer 37

Activate Gs Increase cAMP

Question 38

What is the main cardiac subtype of b adrenoceptors?

Answer 38

b1

Question 39

What are b1 adrenoceptors often described as?

Answer 39

Cardiac subtype

Question 40

What is the main vascular and airways subtype of b adrenoceptors?

Answer 40

b2

Question 41

What are b2 adrenoceptors often described as?

Answer 41

Vascular and airways subtype

Question 42

Where are b3 adrenoceptors mainly found?

Answer 42

Adipose tissue Also in bladder

Question 43

What does NANC stand for?

Answer 43

Non-adrenergic, non-cholinergic

Question 44

What is co-transmission?

Answer 44

Two different neurotransmitters packaged/released together

Question 45

Where is NANC transmission particularly important?

Answer 45

CNS ENS

Question 46

What co-transmission occurs at some sympathetic post-ganglionic fibres/synapses? What does this promote?

Answer 46

Neuropeptide Y, ATP, NA to promote vasoconstriction

Question 47

What co-transmission occurs at some parasympathetic post-ganglionic fibres/synapses? What does this promote?

Answer 47

Nitric oxide, vasoactive intestinal polypeptide, ACh to promote vasodilation

Question 48

What are some sympathetic NS effects?

Answer 48

Increase HR and contractile force Splanchnic vasoconstriction Heart and skeletal muscle vasodilation Increased renin release Bronchodilation Increase blood glucose and free fatty acids Mydriasis Detrusor relaxation Sweating Decreased peristalsis

Question 49

What are some parasympathetic effects?

Answer 49

Decrease HR Increase GI and other secretions Increase peristalsis Bronchoconstriction Visual accommodation Miosis Micturition

Question 50

What are the sympathetic and parasympathetic effects on arteries?

Answer 50

S = vasoconstriction P = no effect in most

Question 51

What are the sympathetic and parasympathetic effects on heart rate?

Answer 51

S = increase P = decrease

Question 52

What are the sympathetic and parasympathetic effects on pupils?

Answer 52

S = dilate (mydriasis) P = constriction (miosis)

Question 53

What are the sympathetic and parasympathetic effects on the GI tract mobility?

Answer 53

S = decrease P = increase

Question 54

What are the sympathetic and parasympathetic effects on the detrusor?

Answer 54

S = maintains relaxation P = constriction

Question 55

What are the sympathetic and parasympathetic effects on exocrine glands?

Answer 55

S = increase salivary and sweat gland secretion P = general increase in secretion

Question 56

What are the sympathetic and parasympathetic effects on metabolism?

Answer 56

S = increase blood glucose P = no effect

Question 57

What are the sympathetic and parasympathetic effects on renin?

Answer 57

S = increase secretion (from kidney) P = no effect

Question 58

Under resting conditions, which ANS division dominates heart rate?

Answer 58

Parasympathetic

Question 59

Where are baroreceptors found?

Answer 59

Carotid sinus Aortic arch

Question 60

Describe the baroreceptor reflex when blood pressure increases

Answer 60

1. Increase BP distends artery walls 2. Stretch stimulates afferent nerve endings of baroreceptors 3. Signal to nucleus tractus solitarius in brain stem (comparator) 4. NTS acts to: - increase parasympathetic drive to heart - decrease sympathetic drive to heart, arteries and veins 5. Since BP = CO x TPR, BP falls to set point

Question 61

How many neurons are in the ENS?

Answer 61

100 million

Question 62

What processes is the ENS responsible for?

Answer 62

Peristalsis Fluid transport Glandular secretion Flow of blood in GI tract

Question 63

What type of drug can be used to block myocardial infarction, hypertension, angina... (sympathetic NS)?

Answer 63

B1 adrenoceptor antagonist

Question 64

What type of drug can be used to treat asthma?

Answer 64

b2 adrenoceptor agonists

Question 65

How do M antagonists affect heart rate?

Answer 65

Speed up heart rate

Question 66

How do M agonists affect peristalsis?

Answer 66

Stimulate peristalsis