ANS: a pharmacological perspective

Question 1

Describe the two different responses to changes in environment

Answer 1

SLOW

FAST ( voluntary and involuntary)

Question 2

Describe the slow response to the changes in environment

Answer 2

Hormones, NTs, growth factors, cytokenisis and other factors that cause changes in gene expression leading to long terms

Question 3

Describe the rapid responses

Answer 3

Voluntary -somatic nervous system acts on the skeletal muscle

Involuntary - ANS acts on the cardiovascular system and other organs. The neuronal groups and fibre groups that control the activity of the heart, visceral organs, blood vessels, glands.
Maintains homeostasis by directly/ indirectly facilitating response of virtually every organ system depending open internal/external glands

Question 4

How is nervous system divided

Answer 4

CNS

PNS

Question 5

How is PNS divided

Answer 5

—> visceral afferents/ other afferents

Question 6

Describe the parasympathetic NS

Answer 6

Mainly for digestion, excretion, visual accommodation

Promotes the couch potato state

less widespread innervation and effects

Question 7

Describe the sympathetic NS

Answer 7

important for ongoing control for cardiovascular system and reflex responses to stressful situations

Fright, fight, fight

More widespread innervation and effects

Question 8

Describe the autonomic ganglion

Answer 8

PREGANGLIONIC —> GANGLION —-> POSTGANGLIONIC —-> MOTOR EFFECTOR JUNCTION on EFFECTOR

Question 9

Salivary gland

Answer 9

parasympathetic preganglionic neurone—> ACh on nicotinic receptors (ganglion) ——-> post ganglionic neurone —–> Ach on muscurinic receptor

Question 10

Blood vessels

Answer 10

sympathetic preganglionic neurone—-> ACh on nicotinic receptors (ganglion) ——-> post ganglionic neurone —–> NA on alpha and beta receptors (adrenergic receptors)

Question 11

sweat glands

Answer 11

sympathetic preganglionic neurone—> ACh on nicotinic receptors (ganglion) ——-> post ganglionic neurone —–> Ach on muscurinic receptor

Question 12

adrenal medulla

Answer 12

sympathetic preganglionic neurone—> ACh on nicotinic receptors (adrenal medulla) ——-> NA, adrenaline —> alpha and beta receptors (adrenergic receptors )

Question 13

Name the two types of cholinergic receptors

Answer 13

Muscarinic receptors

Nicotinic receptors

Question 14

Describe the muscarinic receptors

Answer 14

G protein coupled

5 subtypes: M1 -M5

M2 - ‘cardiac’ —-> G alpha i/o —-> decrease cAMP —-> slow down heart
M3 - ‘smooth muscle/glandular’ G aq —> increase IP3 and DAG —-> cause contraction in visceral muscle

Question 15

Describe the nicotinic receptors

Answer 15

5 subunits

Muscle receptors : N1 - Alpha 1 x2 , Beta 1 , gamma , epsilon

Ganglionic Receptors: Alpha 3 x2, Beta 4 x 3

Non Selective cation channel
Mainly admits Na+/K+
Causes rapid cell depolarisation

Question 16

Name the two adrenergic receptors

Answer 16

Alpha and beta receptors

Question 17

Describe alpha receptors

Answer 17

2 types - alpha 1 and 2 —-> 2 subtypes

Alpha 1 activates Gq - stimulate IP3/Ca2+ and DAG 2nd messenger pathways, raising [Ca2+]

Alpha 2 activates Gi which inhibits adenylate cyclase

Question 18

Describe beta receptors

Answer 18

All activate Gs to increase cAMP

Beta-1 main cardiac subtype
Beta-2 main vascular subtype
Beta-3 Found in adipose

Question 19

NANC

Answer 19

Neither adrenergic or cholinergic

Can occur in ganglionic and post synaptic synapses, particularly important in CNS neuron and ENS

eg Some post ganglionic sympathetic fibres release nucleotides gamma and ATP along with NA —-> VASOCONSTRICTION

Some postganglionic parasympathetic fibres release NO and vasoactive intestinal peptide along with ACh —–> VASODILATION

Question 20

What is co transmission ?

Answer 20

other Its may be released along with ACh/ NA

Question 21

List sympathetic effects

Answer 21

Increase heart rate and force of contraction 
Bronchodilation 
Pupil dilation 
Sweating 
Ejaculation 
Pilorection

Question 22

List parasympathetic effects

Answer 22

Decrease in heart rate

Increase in peristalsis and GI and other secretions