Lecture 15 Flashcards
(13 cards)
What is the function of the ANS?
To control all vegetative functions. It is separate to the voluntary or somatic nervous system
What are the two divisions of ANS?
Sympathetic and parasympathetic
What is the general structure of ANS?
Sympathetic….
Short pre ganglionic and long post ganglionic. Ganglion is located close to CNS.
Parasympathetic….
Long pre ganglionic and short post ganglionic. Ganglion is located in the target tissue.
For both the pre ganglionic is myelinated and post ganglionic is not myelinated
What are the main neurotransmitters in ANS?
Acetylcholine and noradrenaline or norepinephrine in US
What neurotransmitters are used by sympathetic and parasympathetic?
Both use acetylcholine pre ganglion.
Sympathetic uses adrenaline post ganglion (adrenoreceptors) and parasympathetic uses acetylcholine post ganglion however uses muscarinic receptors.
What way are muscarinic, nicotinic and adrenoreceptors set up.
Nicotinic= ion channel
Muscarinic and adrenoreceptors are G protein coupled
Are there post ganglionic sympathetic nerves that are not noradrenergic?
Yes, such as those innervating sweat glands and hair follicles (piloerection)
Are the other transmitters in ANS?
Yes non adrenergic non cholinergic transmitters eg nitric oxide and neuropeptide
What is the third division of the ANS?
Enteric nervous system which controls gastrointestinal system independently of CNS
What is the example of sympathetic post ganglionic neurons that are different?
Chromaffin cells of adrenal medulla. Innervated by pre ganglionic neurons and then release adrenaline on stimulation (neurosecretory cells)
What is somatic nervous system used for?
Skeletal muscle
Parasympathetic innervation examples
Bradycardia on M2 stimulation
Bronchial contraction on M3 stimulation
Sympathetic innervation examples
Tachycardia on B1 adrenoreceptors
Bronchioles relaxation on B2 adrenoreceptors
