lecture 5 - pharmacology of the peripheral nervous system 2

Question 1

describe the characteristics of a sympathetic nerve pathway

Answer 1

1. closer to spinal cord
2. arise form thoracic and lumbar regions
3. short myelinated preganglionic fibre
4. long unmyelinated post ganglionic fibre
5. ACH to noradrenaline

Question 2

Describe the characteristics of a parasympathetic nerve pathway

Answer 2

1. arise from the cranial and sacral areas
2. long myelinated preganglionic fibre
3. short unmyelinated postganglionic fibre
4. ACH to ACH

Question 3

what are cholinergic nerves associated with the activation of

Answer 3

1. all parasympathetic effectors
2. all autonomic ganglia
3. some sympathetic effects (adrenal gland)
4. skeletal muscle contraction

Question 4

what does acetylcholine bind to

Answer 4

nicotinic and muscarinic receptors

Question 5

what does noradrenaline bind to

Answer 5

alpha and beta adrenoreceptors

Question 6

describe cholinergic activity

Answer 6

stimulation of presynaptic terminal triggers the release of ACH which interact with postsynaptic cholinergic receptors

Question 7

what are the 2 main subtypes of cholinergic nerves and explain their effects

Answer 7

1. nicotinic - stimulate effects on autonomic ganglia, adrenal medulla and skeletal muscles
2. muscarinic - stimulate effects on postganglionic nerve endings in cardiac muscle, smooth muscle and glands

Question 8

parasympathomimetics

Answer 8

drugs that mimic the action of ACH

Question 9

describe the process of cholinergic nerve stimulation

Answer 9

1. synthesis - choline to acetylcholine
2. storage - storage of ACH in vesicles on cholinergic neurons
3. release - exocytosis release ACH into synaptic cleft
4. action- ACHesterase attach to receptors on post-synaptic cells and perform action
5. metabolism - ACHesterase break down excess ACH into choline
6. reuptake fo metabolites - excess ACH is taken back into vesicles and repackaged

Question 10

what are the types of Cholinergic drugs and provide examples

Answer 10

1. direct-acting cholinergic drugs - muscarinic and nicotinic inhibitors
2. indirect -acting drugs cholinergic drugs - cholinersterase inhibitors

Question 11

describe cholinergic drug effects

Answer 11

increased GI secretion and motility, increased urinary tract function, pupil constriction and bronchoconstriction

Question 12

symptoms of glaucoma

Answer 12

increased intrapcular pressure, loss of visual field and optic nerve damage, restricted drainage through trabecular meshwork

Question 13

what are the types of glaucoma

Answer 13

primary open angle and acute angle-closure glaucoma

Question 14

symptoms of pilocarpine

Answer 14

constriction of pupil, open inefficient drainage channels

Question 15

what does myadiasis do

Answer 15

dilate the pupil, cause blurred vision by inducing paralysis of the ciliary muscle, preventing accomodation

Question 16

what is xerostomia caused by

Answer 16

drugs with antimuscarinic side effects, other drugs, damage to irridation or disease of the salivary glands

Question 17

how is dry mouth relieved

Answer 17

artificial saliva, muscarinic agonist drugs

Question 18

describe what is palliative care

Answer 18

secretions pooling in the hypopharynx, which causes unpleasant gurgling or rattling

Question 19

how can pallitive care be relieved

Answer 19

positioning, suctioning of the upper airway

Question 20

what is motion sickness

Answer 20

overstimulation of the vestibular apparatus

Question 21

what is motion sickness caused by

Answer 21

cholinergic transmission involved in activating autonomic and emetic centres in the brainstem leading to nausea and vomiting

Question 22

what is bronchoconstriction

Answer 22

acute exacerbations of asthma

Question 23

what is Bradycardia and what is it caused by

Answer 23

abnormal slowing of the heart, caused by drugs

Question 24

function of antimuscarinic drugs

Answer 24

reduce the inhibitory parasympathetic influence

Question 25

how are antimuscarinic drugs administered

Answer 25

intravenously (IV)

Question 26

what is gastric acid secretion stimulated by

Answer 26

parasympathetic nervous system stimulation

Question 27

how does antimuscarinic drugs assist with intestinal spasm

Answer 27

inhibit the contraction of smooth muscle in the bowel walls to reduce motility and relieve spasm

Question 28

symptoms of bladder instability

Answer 28

nocturia, urgency, frequency and incontinence

Question 29

how does antimuscarinic drugs assist bladder instability

Answer 29

reduce symptoms of urgency and urge incontinence and increase bladder capacity

Question 30

describe side effects from taking antimuscarinic drugs

Answer 30

dry mouth, blurred vision, tachycardia, urinary retention, constipation, confusion

Question 31

describe the sites of action of skeletal muscle relaxants

Answer 31

1. CNS - inhibit the firing of somatic neurons 2. neuromuscular junction in the periphery 3. direct on the skeletal muscle

Question 32

describe the function of botox

Answer 32

inhbit the release of ACH from nerve endings which prevent muscle contraction

Question 33

what is the function of local anaesthetics

Answer 33

prevent electrical signal transduction in the afferent division

Question 34

what are the 2 classes of local anaesthetics

Answer 34

ester anaesthetics and amide anaesthetics

Question 35

describe the mechanism of local anaesthetic action

Answer 35

1. block nerve conduction when applied topically to nerve tissue 2. bind to Na+ channels on nerve cell membrane to prevent Na+ from entering the cell 3. the cell cannot depolarise so no actin potential 4. by blocking action potential, prevention of transmissions of sensory signals to the brain 5. block both sensory and motor neurons 6. block smaller fibres first and more rapidly firing neurons

Question 36

state the influences of local anaesthetic action

Answer 36

1. duration of action 2. Inflammation of tissue

Question 37

describe how duration of action influences LA action

Answer 37

dependant on the rate of removal from site of administration

Question 38

describe the ways to administer local anaesthetic

Answer 38

1. topical - on skin or mucous membrane 2. infiltration - injected intradermally or subcutaneously by area to be anaesthetised 3. peripheral nerve block - injection around a nerve trunk 4. central nerve block - injected near the spinal cord 5. intravenous regional - injected into a limb after application of torniquet

Question 39

describe the actions of local anaesthetic on the CNS

Answer 39

1. depress cortical inhibition 2. restlessness, tremors, convolutions 3. CNS depression 4. numbness of tongue, mouth, lips 5. metallic taste, light-headedness, tinnitus 6. slurred speech, muscle twitching

Question 40

describe the actions of local anaesthetic on the cardiovascular system

Answer 40

1. myocardial depressant, arteriolar dilation 2. decreased conduction and force of contraction 3. cardiac arrhythmias 4. cardiac arrest