Autonomic Nervous System Flashcards
To what degree of myelination are the pre- and post-ganglionic fibres?
Pre-ganglionic = small myelinated Post-ganalionic= unmyelinated
Name some structures that ANS neurones effect?
Smooth muscle
Cardiac muscle
Glands
GI neurones
What are the 2 divisions of the ANS?
Sympathetic (fight or flight)
Parasympathetic (rest and digest)
What regions of the spinal cord to sympathetic nerves originate?
Thoracic T1-12
Lumbar L1-2
What is convergence?
Many preganglionic fibres synapsing onto one postganglionic fibre
What is divergence?
One preganglionic fibre synapsing onto several postganglionic fibres
What type of receptors does Acetylcholine work on?
Cholinergic - nicotinic or muscarinic
What type of receptor does Noradrenaline work on?
Adrenergic - alpha and beta receptors
What do preganglionic fibres release during sympathetic nervous system and what receptor does it act on?
Acetylcholine on Nicotinic receptors
What do postganglionic fibres release and what receptor do they act on during sympathetic system?
Noradrenaline on alpha or beta receptors
What cells have no axons but release adrenaline and noradrenaline into the blood?
Postganglionic cells of the adrenal medulla
What do preganglionic fibres release and what receptors do they act on during the parasympathetic system?
Acetylcholine on nicotinic receptors.
What do postganglionic fibres release and what receptors do they act on during parasympathetic system?
Acetylcholine on muscarinic receptors
Give some effects that the sympathetic system produces?
Airways dilate Heart beats faster Heart beats stronger Blood goes to muscle Gut motility decreases Gut enzyme secretion inhibited Stored energy is released Pupils dilate Eyes focus far away Hair stands on end Mouth gets dry
Give some effects the parasympathetic system produces?
Airways constrict Heart beats slower Heart beats weaker Blood goes to gut Gut motility increases Gut enzyme secretion is stimulated Energy is stored Pupils construct Eyes focus close up Hair lies flat Mouth starts drooling
What receptors relax smooth muscle?
Beta -2