W5 - Autonomic NS Flashcards
How does information get from the PNS to the CNS?
Afferent sensory/visceral neurons (autonomic/somatic)
How does information get from the CNS to the PNS?
Efferent motor neurons (autonomic/somatic)
What are the two divisions of the autonomic NS?
Parasympathetic and sympathetic
What two things can the autonomic NS act upon?
Muscles and glands
Where are the parasympathetic nerves coming from?
Craniosacral region
Where are the sympathetic nerves coming from?
Thoracolumbar region
If the spinal cord is damaged, why does the heart still beat?
It’s myogenic
If someone is paraplegic (having damaged their SC at the neck) what does their heart rate usually do?
It tends to slow as symp cant work and para can
Is the pre/post ganglionic neuron in para/symp NS short or long?
Para - pre is long, post is short. Sympathetic - pre in short, post is long
What is special about the preganglionic neurons in either the parasympathetic/sympathetic NSs?
They’re always myelinated
What is it called where the pre/post ganglionic fibres meet?
A ganglion
Do the ganglia in symp/para NS sit closer to the CNS or the target organ?
Symp - closer to CNS, para - closer to target organ
What NTM do preganglionic fibres use irrespective of if its symp/para?
Acetylcholine
The ratio of neurons aren’t 1:1, which out of symp/para have pre fibres that innervate >20 cell bodies or <4 cell bodies in the ganglia?
Symp - >20, para - <4
What are most of the sympathetic ganglia arranged into?
Paravertebral ganglia
What are other sympathetic ganglia that are located further away called?
Prevertebral ganglia
What NTMs do the post ganglionic cells use in the symp/para NSs?
Symp - norepinephrine, para - acetylcholine
What receptors are present on post ganglionic cells and the target organs in the sympathetic NS?
Post gang - nicotinic receptors, target organ - adrenoreceptors
What receptors are present on post ganglionic cells and the target organs in the parasympathetic NS?
Post gang - nicotinic receptors, target organ - muscarinic receptors
List stages of release of ACh across synapse (3)
- ACh made from choline and acetyl coA and packaged into vesicles 2. Exocytosis and diffusion across cleft 3. Binding to receptors
Are nicotinic or muscarinic cholinergic receptors ionotropic or metabotropic?
Nic - ionotropic, Musc - metabotropic
The agonists for the nicotinic, ligand binding ionotropic receptors are ACh, nicotine and carbachol, what is the antagonist?
Curare
The agonists for the muscarinic G-protein receptors are ACh, muscarine and carbachol, what are the antagonists?
Atropine and scopolamine
Where are the nicotinic receptors found? (3)
Neuromuscular junctions, ganglionic neurons and adrenal medulla
Where are the muscarinic receptors found? (3 examples but there is more)
Gut, heart, bronchioles
What type of receptors are adrenoreceptors?
Metabotropic GPCRs
There are 4 subtypes of adrenoreceptors, what is different between them all?
The sensitivity to NE compared to E
Depending on if it’s an ionotropic/metabotropic receptor, does ligand binding directly/indirectly alter the membrane permeability?
iono - directly, metabo - indirectly
