Lecture 5 : Autonomic nervous system Flashcards
what are the two neuron chain of the ANS
- the preganglionic neuron extends from the CNS to the ganglion
- the postganglionic neuron extends from a ganglion to an effector organ.
what does Preganglionic fibers release
ACh
what does posrganglionic fibers release
Norepinephrine if its sympathetic
ACh is parasympathetic
Roles of the parasympathetic Division
involves the D activities- digestion, defecation and diuresis.
Activity is illustrated in person who relaxes after a meal
- blood pressure, heart rate and respiratory rates are low-
-gastreointestinal activity is high
Roles of the sympathetic Division
involves the E activities- exercise, excitement, emergency and embarrassment
illustrated by a person who is threatened
- heart rate increases, and breathing is rapid and deep
- skin is cold and sweaty and the pupils dilate.
Cholinergic fibers
ACh releasing fibers. ACh is released by all preganglionic axons and all parasympathetic post ganglionic axons
Adrenergic fibers
Norepinephrine releasing fibers. Norepinephrine is released by sympathetic postganglionic axons
Cholinergic Receptors
2 types of receptors than bind ACh are nicotinic and muscarinic.
Nictonic receptors are found on all postganlionic neurons of both sympathetic and parasympathetic divisions.
Muscarinic receptors occur on all parasympathetic targets.
Adrenergic Receptors
Bind norepinephrine from sympathetic postganglionic neurons.
the 2 types of adrenergic receptors are alpha and beta
Adrenergic Receptors
bind to Norepinephrine
Alpha 1
constricts blood vessels in skin and abdominal viscera, dilates pupils
Alpha 2
inhibits insulin, stimulates clotting
Beta 1
increases HR
Beta 2
dilates blood vessels and bronchioles in lungs, relaxes digestive and urinary organs.
Beta 3
stimulates lipolysis of adipose
