Membranes and receptors - 10 Flashcards
Where do parasympathetic nerves originate from?
Lateral horn of the medulla and sacral regions of the spinal cord.
Where can you find the ganglia of parasympathetic nerves?
They are often located in the tissues that they innervate.
Where do sympathetic nerves originate from?
Lateral horn of the lumbar and thoracic spinal cord.
Which of the post ganglionic and pre-ganglionic nerves are myelinated and which unmyelinated?
Pre-ganglionic are myelinated
Post-ganglionic are unmyelinated
Where are the ganglia of sympathetic nerves found?
In the paravertebral chain close to the spinal cord or in the case of the GI and GU tract nerves they are located in the prevertebral chain (midline).
What type of receptor are nicotinic acetyl choline receptors?
Ligand-gated ion channels.
What type of receptors are muscarinic acetyl choline receptors?
G-protein coupled receptors.
What type of receptors are adrenoreceptors?
G protein-coupled receptors.
What is the general structure of G-protein coupled receptors?
Single polypeptide chain, 7 -transmembrane spanning regions, extracellular N-terminal and intracellular C-terminal. Two regions that ligand can bind to:
- For some receptors it is formed by 2-3 of the transmembrane spanning domains
- In others the N-terminal region and other extracellular domains form the ligand binding site.
Which sympathetic post-ganglionic neurons are cholinergic, not adrenergic?
Those innervating the sweat glands and hair follicles (piloerection).
Apart from ACh and NA, what other transmitters are found in the ANS?
Non-Adrenergic, Non-Cholinergic (NANC) transmitters e.g. ATP, NO, 5HT (serotonin), neuropeptides ( (VIP) vasoactive intestinal peptide, substance P).
What are chromaffin cells?
They are postganglionic sympathetic neurons that do not project to a target tissue. They are found in the adrenal gland and on sympathetic stimulation release adrenaline into the bloodstream.
What type of receptor is present at the neuromuscular junction of the somatic efferent system?
nicotinic acetyl choline receptors.
What are dysautonomias?
Dysautonomia is an umbrella term used to describe several different medical conditions that cause a malfunction of the Autonomic Nervous System.
Give an example of a cause of primary dysautonomia:
Phaeochromocytomas. A phaeochromocytoma is a rare tumour that secretes catecholamines. It is derived from chromaffin cells, usually in the adrenal medulla but occasionally extra-adrenal phaeochromocytomas or paragangliomas occur.
