PHAR232 - ANS revision Flashcards
Note - almost all PNS arise from the brainstem and almost all SNS arise form the spinal cord (exception being bladder and genitals)
Important to note!
Majority of lung tissue is parasympathetic
- which is why ADRENALIN is important because it’s a hormone
NOT noradrenaline to which is a NT
Where does the small amount of SNS fibers go into the lungs?
Upper part of the airway
Why are there NO SNS neurons in the lungs?
To avoid complete constriction upon SNS activation
How does the SNS REGULATE lung tissue, if they don’t have SNS neuronal fibres linking to the lungs?
Via - Beta-2 adrenergic receptors
Are the lung bronchioles mediated by adrenaline or noradrenalin?
ADRENALINE
(It’s a hormone NOT a neurotransmitter)
At rest what is the control of the lungs regulated by the ANS? SNS or PNS?
PNS is control of the lungs at rest
BUT there are no receptors for PNS in the lungs - it’s all about adrenalin and beta-2 adrenergic receptors
due to being mediated by the beta-2 adrenergic receptors (via adrenaline the hormone)
What is a synapse between 2 neurons called?
autonomic ganglion
What is the CNS to ganglia called?
Pre-ganglionic neuron
(ALWAYS originates in the CNS and is myelinated)
Are pre-ganglionic neurons myelinated?
yes
What is it called to connect the ganglia to an organ?
post-ganglionic neuron
UNMYELINATED and terminates at the EFFECTOR ORGAN
Why does the SNS have a longer 2nd neuron?
Hypothesis:
Quicker reaction when required
What is the ganglion?
The synapse between a pre-ganlionic neuron and a post-ganglionic neuron
Is the 2nd neuron myelinated or unmyelinated?
unmyelinated
Is the pre-ganglionic neuron in the PNS long or short?
long (Hint: PNS is a longer word)
What is the short ganglion in the PNS? Pre or Post?
Post-ganglion in PNS is short
In the SNS is the preganglionic neuron short or long?
Short (hint - SNS is a shorter word)
What is the long ganglion in the SNS? Pre or Post ganglionic neuron?
Post
SYMPATHETIC PATHWAYS
PARASYMPATHETIC PATHWAYS
At heart the rest is PNS or SNS?
Primarily PARASYMPATHETIC
In the heart - heart has more SNS neurons than PNS
= Significant SNS influence upon activation
What do ALL PNS and SNS fibres release pre-ganglionic?
ACh
= Cholinergic fibers
What are ALL post-ganglionic cells expressing if all pre-ganglionic fibres are cholinergic and releasing ACh?
nAChRs (BOTH PNS AND SNS)
What do ALL PNS post-ganglionic fibres release?
ACh
What type of post-ganglionic fibres are in PNS?
cholinergic
Releases ACh
If all PNS post-ganglionic fibres release ACh and are cholinergic, what would be the target organ receptors?
mAChRs
What type of receptor is nAChRs?
Ion gated channels
SO THEY ARE FAST
What type of receptors are on PNS target organs?
mAChRs = GPCR
(LESS URGENT = SLOWER)
what do MOST SNS post-ganglionic fibres release?
Noradrenline
What type of fibres are SNS post-ganglionic neurons?
Adrenergic fibres
= NA
What are the target receptors for SNS post-ganglionic adrenergic fibres?
Alpha or Beta Adrenergic Receptors
What 3 post-ganglionic SNS fibres release ACh???
- Skin
- Sweat glands
- Skin blood vessels
REMEMBER: S, S, S
What type of RECEPTORS would skin, sweat glands and skin blood vessels have for SNS ACh transmission?
mAChRs = NOT AS IMPORTANT
= slower
= BUT still controlled by SNS
= Want to be controlled by SNS to support ‘fight flight’ running and heat = want to cool and increased sweat
What does the adrenal medulla release in response to post-ganglionic SNS stimulation on the nAChRs??
Adrenaline NOT noradrenaline
= Hormone
= Blood stream
Draw out just to reiterate lol
Does noradrenalin like Beta 2 receptors?
not primarily
Where do you find nicotinic ACh receptors?
- Neuromuscular junction
- Autonomic ganglia
- Brain
Where do you find mAChRs?
- Heart
- Glands
- Eyes
- Lungs
- GI
Remember mAChRs = PNS
where do you find alpha NA and Adrenaline receptors?
Blood vessels
GI
Brain
Where do you fine beta NA and adrenaline receptors?
heart,
lungs
kidney
brain
Summary - review and draw
