ANS Flashcards

1
Q

what does the ANS do?

A

controls involuntary functions

e.g heart rate, blood pressure, GI motility , iris diameter

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

what are the two divisions of the ANS and what do they do

A

sympathetic- responds to stressful situation. fight or flight response. increases heart rate, force of contraction and blood pressure.
parasympathetic-regulates basal activities. rest and digest.

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

which regions of the spinal column do the two divisions arise from

A

parasympathetic-cranial and sacral region

sympathetic- thoracic and lumbar

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

describe the general structure of the ANS

A

pre-ganglionic and post ganglionic parts
ganglion is part at which synapses occur
pre-ganglionic part is myelinated

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

what neurotransmitters r used in the ANS

A

ACh and noradrenaline
all pre ganglionic neurone are cholinergic (use ACh) and activate nicotinic ACh receptors (ligand-gated ion channels)
parasympathetic post-ganglionic neurons are also cholinergic (release ACh that acts on muscarinic ACh receptors, these are GPCRs )
most sympathetic post-ganglionic neurons are noradrenergic

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

what does NA interact with

A

adrenoceptors
two classes- alpha and beta
can be further divided into a1,a2,b1,b2

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

what type of receptors are m1-m5 muscarinic acetylcholine receptors and all adrenoceptors

A

GPCR

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

not all sympathetic post-ganglionic neurons are noradrenergic. what re the exceptions?

A

they are instead cholinergic
-those innervating sweat glands, hair follicles
release ACh that acts at muscarinic ACh receptors

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

sympathetic postganglionic neurons in the adrenal glands

A

differentiated to from neurosecretory chromaffin cells
chromatin cells can be considered as postgamglionic sympathetic neurons that do not project to a target tissue, instead release adrenaline into blood stream

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

what does parasympathetic release of ACh cause in the heart and what receptor type

A

SA node- bradycardia
AV` node- reduced cardiac conduction velocity
M2

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

what does parasympathetic release of ACh cause in smooth muscle and what receptor type

A
M3
bronchial contraction 
increased intestinal mobility/secretion 
bladder contraction and relaxation 
penile erection 
ciliary muscle and iris sphincter contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does parasympathetic release of ACh cause in glands and what receptor type

A

M1/M3

increased sweat/ salivary /lacrimal secretion

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

what does sympathetic release of NA cause in the heart and what receptor type

A

SA node- tachycardia
ventricles- positive inotropy
B1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does sympathetic release of NA cause in smooth muscle and what receptor type

A
arterial contraction(a1) in non flight essential arterioles and relaxation in essential ones (b2)
bronchiolar relaxation -b2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how is the output from the ANS regulated

A

afferent/sensory inputs
e.g blood o2 detected by carotid body , chemoreceptors etc
sensory neurones monitor co2, o2 and nutrients in blood

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

most common sites of drug action in neurotransmission

A

degradation of neurotransmitter
interaction with post synaptic receptors
inactivation of transmitter
re-uptake
interaction with pre ganglionic receptors

17
Q

acetylcholine synthesis equation

A

acetyl CoA +choline (from diet)——–> acetylcholine +coenzyme A
enzyme is choline acetyltransferase
ACh is packed into vesicles here

18
Q

ACh degradation equation

A

ACh———->acetate +choline
this is when ACh is released from vesicle
enzyme is cholinesterase

19
Q

why can drugs have actions selectively at autonomic system

give example

A

nicotinic acetylcholine receptors at autonomic ganglia and the neuromuscular junction differ in structure therefore can have actions selectively
e.g ganglion blocking drug trimethaphan (antihypertensative)

20
Q

what is the problem with cholinergic cells and what would a non-selective muscarinic EACh receptor agonist do

A
lack of sensitivity 
unwanted side effects 
decrease heart rate and cardiac output 
increase bronchoconstriction
increase sweating and salivation
21
Q

what is SLUDGE syndrome

A

pathological effects of massive discharge of parasympathetic NS
Salivation: stimulation of the salivary glands
Lacrimation: stimulation of the lacrimal glands
Urination: relaxation of the internal sphincter muscle of urethra, and contraction of the detrusor muscles
Defecation
Gastrointestinal distress: Smooth muscle tone changes causing gastrointestinal problems, including cramping
Emesis: Vomiting[

22
Q

when is sludge syndrome encountered

A

drug overdose
ingestion of magic mushrooms
exposure to organophosphorus insecticides
exposure to nerve agents
the last two agents covalently modify acetcholinesterase to irreversibly deactivate enzyme and rats ACh levels

23
Q

what are the symptoms of SLUDGE due to

A

prolonged stimulation of muscarinic ACh receptors in rogans and muscles innervated by PNS.

24
Q

how is sludge treated

A

atropine

pralidoxime

25
name two muscarinic ACh receptor agonists
pilocarpine-treat glaucoma | bethanechol-stimulate bladder emptying
26
name some muscarinic ACh receptor antagonists
ipratropium + tiotropium- for asthma and COPD tolterodine, darifenacin,oxybutynin-treat overreactive bladder hyoscine(scopolamine)-IBS
27
post ganglionic sympathetic neurons structure
posses a highly branching axonal network with numerous varicosities, each of which is specialised site for Ca2+-dependent vesicular noradrenaline release.
28
noradrenaline synthesis
Tyrosine to DOPA to Dopamine to NA
29
what does NA interact with and for what
NA interacts with adrenoceptors in post-synaptic membrane to initiate signalling in the effector tissue NA interacts with pre-synaptic adrenoceptors to regulate processes within nerve terminal. however NA only has a very limited time to influence pre and post synaptic adrenoceptors as its rapidly removed from synaptic cleft by NET(NA transporter protein)
30
what type of drug is salbutamol and what is it used for
in inhalers for asthma to oppose bronchoconstriction | B2-adrenoceptor-selective agonist
31
what can a1 and b1 adrenoceptor- selective antagonists treat
cvs disorders like hypertension