autonomic NS innervates…
all effector organs EXCEPT skeletal muscle
dual innervation
organs innervated by both division, used by para and sympa
sympathetic
thoraco-lumbar
CNS to effectors
active during activity and stress
sympathetic results
decreases GI activities
pupillary dilation
increases hr/bp
mobilizes energy stores, takes glycogen from muscles, fats, etc
parasympathetic
cranial/sacral to effectors
active during quiet/relaxed states
parasympathetic results
increases GI activity
decreases hr/bp
pupillary constriction
how long are autonomic pathways
generally two neurons long
sympathetic pathways (steps)
- pregang neuron (cholinergic)
- sympathetic chain OR collateral ganglion
- postgang neuron (adrenergic)
- effector organ (adrenergic receptors)
parasympathetic pathways
- pregang neuron (cholinergic)
- parasympathetic ganglion
- postgang neuron (cholinergic)
- effector organ (muscarinic receptors)
pregang neurons are always
cholinergic
sympathetic postgang neurons
adrenergic
parasympathetic postgang neurons
cholinergic
adrenergic receptors
respond to norepinephrine
found at all sympathetic effector organs
two classes: alpha, beta
alpha adrenergic receptors
most common
usually excitatory
greater affinity to norepi
beta adrenergic receptors
G-protein system, increases cAMP
activated by both norepi and epi
cholinergic receptors
respond to acetylcholine
two classes: nicotinic, muscarinic
nicotinic cholinergic receptors
@ dendrites of postgang
@ adrenal medulla
@ skeletal muscles
function: open Na+ and K+ channels
when nicotinic receptors open Na+ channels…
they are EPSP’s
when nicotinic receptors open K+ channels…
they are IPSP’s
muscarinic receptors location
all parasympathetic effector organs
muscarinic receptor function
g-protein system
opens/closes ion channels
what does the somatic nervous system control
skeletal muscle
somatic ns pathway
one MOTOR neuron between cns and effector organ
somatic motor neuron releases
Ach
