Sympathetic And Parasympathetic Nervous Systems

Question 1

Effects of the sympathetic nervous system

Answer 1

Fight or flight Increased heart output Increased blood flow Increased respiration Reduced digestion More glucose in blood More saliva Inhibition of urination pupil dilation Sweating Orgasm

Question 2

Noradregenic neurotransmission mechanism

Answer 2

1. Tyrosine synthesized to noradrenaline (via dopamine)
2. All products of noradrenaline synthesis such as dopamine are called monoamines and they geat broken down by the enzyme monamine oxidase. Noradrenalie escapes this by being stored in in vesicles called VMAT (can be inhibited by reserpine)
3. Released into synapse, causing negative feedback by binding to presynaptic alpha2 receptors and preventing further release. Reuptake via uptake 1 channels.
4. Interaction with adrenergic receptors (in smooth muscle alpha In cardiac muscle beta)
5. Inactivation of signal by breakdown of NA by enzymes monoamine oxidase and COMT. Also reuptake by uptake 1 channel (neuron) and uptake 2 channel (non neuron cell)

Question 3

What alpha 1, Alpha 2, beta 1 and beta 2 receptors innervate

Answer 3

A1: smooth muscle p, bladder, intestines p, pupil, liver, ejaculation

A2: widespread. INHIBITS transmitter release

B1: cardiac muscles

B2: smooth muscle Vasodilation Broncodilation, glycogen mobilizations

Question 4

Parasympathetic pathway of transmission

Answer 4

Acetylcholine to nicotinic then acetylcholine to muscarinic

Question 5

Sympathetic pathways of transmission

Answer 5

Acetylcholine to nicotinic then noradrenaline to alpha and beta adrenergic receptors (blood vessel) Acetylcholine to nicotinic then noradrenaline to muscarinic (sweat glands) Acetylcholine to nicotinic then through blood as adrenaline then acts on alpha and beta adrenergic receptors (

Question 6

Muscarinic receptors structure and second messengers.

Answer 6

G protein. 5 subtypes 2 of which are important:

M2 (cardiac) lowers cAMP

M3 (smooth muscle/ glands) increased IP3 and DAG causing contraction

Question 7

Adrenergic receptors (2 alpha and 2 beta subtypes) what second messengers are invloved and effect

Answer 7

Alpha and beta subtypes

Alpha 1: stimulates IP3/ Ca and DAG - increases calcium levels

Alpha 2: inhibits adenylate cyclase lowers cAMP - decreases release of noradrenaline

Beta: increase cAMP

B1 cardiac

B2 vascular airways

B3 adipose p, bladder

Question 8

Nicotinic receptors

Answer 8

Non selective action channels, causes depolarization of membrane

Question 9

Non cholinergic , non adrenergic neurotransmission examples of things they release causing vasodilation/ vasoconstriction.

Answer 9

Some fibers release other neurotransmitters or cofactors. Called NANC

Vasodilation: Nitric oxide, intestinal polypeptides along with Ach

Vasoconstriction: Neuropeptide Y and ATP released along with noradrenaline.

Question 10

Parasympathetic effects on heart

Answer 10

Decrease heart rate, cardiac output, blood pressure

Reduced conduction velocity in AV node

Question 11

Parasympathetic effects in blood vessels

Answer 11

Causes vasodilation (e.g. causing penis erection)

Mediated by vagus and sacral nerves BUT small role of PNS on this. Because very few vascular beds are parasympathetically innervated.

Question 12

Parasympathetic effects on other smooth muscle

Answer 12

Non vascular smooth muscle is contracted (bronchioles, GI tract contracts except sphincters that relax)

Question 13

Parasympathetic effects on secretion and nerves affected

Answer 13

Bronchosecretion (vagus)

Gastrointestinal secretions (vagus)

Salivary secretions (glossopharyngeal)

Lacrimal glands (fascial nerve)

Question 14

Parasympathetic effects on the eye and associated nerve

Answer 14

Accommodation for near vision by contraction of ciliary muscle Pupil constriction by contraction of sphincter papillae muscle.

Mediated by oculomotor nerve

Question 15

Botulinum toxin. What it does and what it can be used to treat.

Answer 15

Binds to and degrades receptor responsible for exocytosis of ACh amongst other neurotransmitters

Is used as a drug to treat overactive bladder

Question 16

Enteric nervous system

Answer 16

Made up of myenteric and submucosal plexuses which control most functions of the gut. Parasympathetic and sympathetic effects on gi tract occur via modulation of enteric NS

Question 17

2 types of cholinergic receptors

Answer 17

muscarinic (Glands) and nicotinic (ganglionic transmission)

Question 18

Cholinergic neurotransmission: how it works from neuron to synapse and what enzymes are involved

Answer 18

Question 19

Sympathetic effect on: the heart, arteries and veins and respiratory system

Answer 19

Question 20

Sympathetic effects on: the gut, metabolism, salivary glands and bladder

Answer 20

Question 21

Sympathetic effect on: sexual function, the eye and the skin

Answer 21

Question 22

Reuptake of noradrenaline in synapse. 3 different ways it is recycled.

Answer 22

1. Uptake 1 receptors
2. Uptake 2 receptor (uptake in tissue and metabolism by COMT)
3. MAO breaksdown adrenaline by converting it to noradrenaline aldehyde then aldehyde dehydrogenase to DOMA.

Question 23

What adrenergic receptors (alpha 1 and 2, beta 1 and 2) the following sympathomimetic drugs influence.

Answer 23

Question 24

Effect of phentolamine (alpha adrenergic blocker)

Answer 24

Non selective alpha blocker. Both reuptake receptor and effector receptor are inhibited.

Question 25

Effect of prazosin (alpha drenergic blocker)

Answer 25

Alpha 1 selective blocker. So alpha 2 reuptake is not affected only effector alpha 1 receptor.

Question 26

Main effect of beta 1 and 2 adrenergic blockers and specific effect of:

Labetalol

Atenolol

Salbutamol

Answer 26

Beta 1 blockers: sympathetic cardiac function reduced

Beta 2 blockers: respiratory and birth sympathetics reduced

Labetalol: non selective beta 1 and alpha 1 blocker.

Atenolol: selective b1 blocker

Salbutamol: slective b2 agonist (used for bronchodilation in asthma)