M&R Session 10 Flashcards
Is the ANS efferent, afferent or both?
Entirely efferent
What type of input regulates the ANS?
Afferent inputs
Where do parasympathetic nerves originate from?
Lateral horn of medulla and sacral spinal cord
Describe parasympathetic pre-ganglionic neurones.
Long
Myelinated
Describe parasympathetic post-ganglionic neurones.
Short
Unmyelinated
Where are the ganglia in the parasympathetic division of the ANS?
Target tissues
Where do sympathetic nerves originate in the sympathetic nervous system?
Lateral horn of lumbar and thoracic spinal cord
Describe sympathetic preganglionic nerves.
Short
Myelinated
Describe sympathetic postganglionic nerves.
Long
Unmyelinated
Where are sympathetic ganglia found?
Paravertebral chain
Which neurotransmitter is used in all preganglionic neurones?
ACh
What type of receptors are found on postganglionic neurones in both the sympathetic and parasympathetic nervous systems?
Nicotinic AChR
Which neurotransmitter and corresponding receptor do postganglionic parasympathetic neurones use?
ACh
mAChR
Which type of neurotransmitter and corresponding receptor do postganglionic sympathetic neurones utilise?
NA
Alpha and beta adrenoceptors
How may genes code for adrenoceptors in the human genome?
9
Are all sympathetic postganglionic neurones noradrenergic?
Nope
Which sympathetic postganglionic neurones are cholinergic?
Sweat glands
Piloerector muscles
When can NANC transmitters be released?
Coreleased w/NA or ACh
Give four examples of NANC transmitters.
ATP
Nitric oxide
5-hydroxytryptamine
Neuropeptide
How is ATP used as a NANC transmitter?
Copackaged into vesicles, especially w/NA
What does ATP use as a NANC transmitter regulate?
BP
Give two examples of neuropeptides used as NANC transmitters.
Vasoactive intestinal peptide
Substance P
What do sympathetic postganglionic neurones in the adrenal glands differentiate to form?
Neurosecretory chromaffin cells
What is the function of chromaffin cells?
Release adrenaline into blood
What type of receptors are found in chromaffin cells?
nAChR
Which area/s of the heart does parasympathetic ACh release act on?
Atria - sparse if any input to ventricles
What two effects does activation of M2 receptors by ACh have in the heart?
SAN –> bradycardia
AVN –> decrease cardiac conduction velocity
Which receptor subtype is found in the lungs and GI tract and is activated by ACh?
M3
What is the affect of ACh release on the lungs and GI tract?
Lungs - bronchial contraction
GI - increased mobility and secretion
What are the effects of ACh release on the GU tract?
Bladder contraction
Sphincter relaxation
Penile erection (increased bloodflow)
What is the affect of ACh release on the eye?
Ciliary muscle and iris sphincter contraction
What causes the increase in bloodflow which causes penile erection?
Nitric oxide
Which receptor type is found in glandular tissue which is activated by ACh release?
M1/3
What is the affect of M1/3 activation by ACh in glandular tissue?
Control level and composition of secretion
Which component of the lungs, GI tract, GU tract and eye is affected by ACh release?
Smooth muscle
What does the ANS exist in parallel but separate to?
Somatic nervous system
What effects does NA release have on the heart?
SAN –> +ve chronotropy
Ventricle –> +ve inotropy
Which receptors are activated in the heart by NA?
Beta-1 (mainly)
Beta-2
What does the balance of beta-1 and beta-2 receptors in the heart depend on?
The individual
What affect does NA release have on the smooth muscle of the vasculature?
BV contract
Arteriolar relaxation in some vascular beds
What type of receptors constrict visceral BV upon NA release?
Alpha-1