Autonomic Nervous System 1 Flashcards
What does the ANS control and where is it found?
- Controls all involuntary functions
- Found peripherally
What are the 2 component systems of the ANS and what is their main function?
Sympathetic - stress response
Parasympathetic - basal activities
What are the 2 principle neurotransmitters in the ANS?
Acetylcholine (ACh)
Noradrenaline (NA)
Where does the parasympathetic nervous system originate?
In the lateral horn of the medulla and sacral spinal cord
Describe the length and myelination of pre and postganglionic neurons in the parasympathetic nervous system
- Long myelinated preganglionic fibres
- Short unmyelinated postganglionic fibres
Where are the ganglia located in the parasympathetic nervous system?
Within the innervated tissues
Where does the sympathetic nervous system originate?
The lateral horn of the lumbar and thoracic spinal cord
Describe the structure and myelination of pre and postganglionic neurons in the sympathetic nervous system
- Short myelinated preganglionic fibres
- Long unmyelinated postganglionic fibres
Where are the ganglia located in the sympathetic nervous system?
The paravertebral chain close to the spinal cord
Which neurotransmitter is found in preganglionic neurons and which receptor does it bind to?
- Acetylcholine (cholinergic)
- Bind to nicotinic ACh receptors
- Ligand-gated ion channels
Describe the neurotransmitter and receptor involved in parasympathetic postganglionic neurons
- ACh
- Bind to muscarinic ACh receptors
- G-Protein coupled receptors
How many receptor subtypes are found in the parasympathetic nervous system?
- 5
- M1 - M5
Which neurotransmitter and receptor are found in the postganglionic sympathetic nervous system?
- Noradrenaline (noradrenergic)
- Bind to alpha and beta adrenoceptors
What are the 5 subtypes of sympathetic postganglionic receptors?
- Alpha 1 and 2
- Beta 1, 2 and 3
Which nervous system can be considered the third part of the ANS?
Enteric Nervous System which controls the GI system
What do sympathetic postganglionic neurons differentiate to in the adrenal glands?
Chromaffin cells
What is the function of Chromaffin cells?
Release adrenaline into the bloodstream on sympathetic stimulation
Which part of the adrenal glands contain Chromaffin cells?
Adrenal medulla
Name a target and effect for each of the muscarinic receptors when ACh is released
M1 - glandular tissue - saliva secretion
M2 - heart - bradycardia/reduced contractility
M3 - smooth muscle - bronchial constriction
Name a target and effect for each of the noradrenergic receptors A1, B1 and B2 when noradrenaline is released
A1 - smooth muscle - blood vessel contraction
B1 - heart - tachycardia, increased contractility
B2 - smooth muscle - bronchial relaxation
