Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BDS2 BAMS Oral Biology > 14. Local Anaesthetics > Flashcards

14. Local Anaesthetics Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

How do LAs work

A

Stop nerve conduction by blocking voltage-gated Na channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

LA efficacy depends on (2)

A

Concentration of solution

Type of nerve being anaesthetised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Nerve susceptibility to block by LA (4)

A

A-delta
C-fibres
A-beta
A-alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mechanism of LA action (4)

A

LA binds to site in Na channel
LA blocks channel, preventing Na influx
This blocks AP generation and propagation
Block persists so long as sufficient number of Na channels are blocked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Composition of LAs (3)

A

Organic molecules
Presented as hydrochloride (B.HCl)
Partly dissolved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Organic molecule composition of LA (3)

A

Aromatic region (hydrophobic)
Ester/amide bond
Basic amine side chain (hydrophilic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

LA dissolution features (2)

A

Active in ionised form

Crosses membrane in un-ionised form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Are smaller/larger axons more susceptible to LA and why

A

Small - fewer Na channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where are Na and K channels concentrated in myelinated axons

A

Nodes of Ranvier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

LA blocks AP by

A

Acting on several nodes of Ranvier along the axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Types of LA (2)

A

Esters

Amides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Examples of ester LAs (3)

A

Benzocaine
Cocaine
Procaine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Examples of amide LAs (6)

A 
Lignocaine (lidocaine)
Prilocaine
Articaine 
Bupivacaine
Ropivacaine
Mepivacaine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Are LAs vasodilators or vasoconstrictors

A

Vasodilators so contain vasoconstrictors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Function of vasoconstrictors in LA (2)

A

Reduce blood flow

Increase duration of action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Local action of adrenaline

A

Vasoconstriction (on a-receptors)

17
Q

Systemic effect of adrenaline (3)

A

Lowers TPR (b > a)
Increases CO
Little/no effect on MABP

18
Q

Local effect on noradrenaline

A

Vasoconstriction (more effective on a-receptors than b-receptors)

19
Q

Systemic effect of noradrenaline (3)

A 
Increases TPR (a > b)
Increases CO
Raises MABP (can result in fall in BP - overcompensation)
20
Q

How are ester type LAs broken down

A

By tissue esterases (brief action)

21
Q

How are amide type LAs broken down

A

By liver amidases (longer duration of actioN0

22
Q

Modes of LA administration (6)

A 
Topical (surface application)
Injection
Local infiltration
Regional nerve block
Nerve root block (spinal, epidural)
Intravenous
23
Q

Max. safe dose of adrenaline

A

500ug

24
Q

Adrenaline in one lidocaine cartridge (2%, 1:80,000, 2.2ml)

A

27.5ug

25
Q

MAx. safe dose of lidocaine

A

Approx. 4mg/kg body weight

BDS2 BAMS Oral Biology (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions