What is the ANS

autonomic nervous system

what is somatic motor division?

it is voluntary control of skeletal muscle

how does somatic motor division function?

single motor neuron runs all the way from CNS to muscle releases acetylcholine onto nicotinic receptors

what is autonomic division?

involuntary control of smooth muscle, cardiac miuscle, and glands

in autonomic division, what kind of chain exists?

ALWAYS a two neuron chain

explain the process of the 2-neuron chain

preganglionic neuron leaves CNS synapses in a ganglion postganglionic neuron carries signal to target

how many neurons are there from CNS to target?

somatic = 1 autonomic = 2

Sympathetic system AKA

fight or flight

parasympathetic system AKA

rest and digest

sympathetic system origin

thoracolumnar region basically from T1 - L2

sympathetic system ganglia

located close to spinal cord

sympathetic system fiber lengths

short Preganglionic, long Postganglionic

sympathetic system main transmitter

Norepinephrine

Parasympathetic system origin

cranial nerves, mostly vagus nerve

Parasympathetic system ganglia

close to or inside target

Parasympathetic system fiber lengths

Long preganglionic, short postganglionic

Parasympathetic system main transmitter

Acetylcholine

Sympathetic vs parasympathetic: heart

symp = rate UP, contractility UP para = rate DOWN

Sympathetic vs parasympathetic: bronchioles

symp = dilate para = constrict

Sympathetic vs parasympathetic: GI tract

symp = motility DOWN, secretion DOWN para = motility UP, secretion UP

Sympathetic vs parasympathetic: pupil

symp = dilate (sees threat) para = constricts

Sympathetic vs parasympathetic: bladder

symp = relaxed detrusor, tightened sphincter (no peeing) para = contracts detrussor

Sympathetic vs parasympathetic: blood vessels

symp = constricts para = little direct effect

what kind of innervation do most organs recieve?... how does it work?

dual, antagonistic... two branches go against eachother and organ listens to the balance of the 2, not just 1

how is the adrenal medulla an exception to signalling?

has NO postganglionic neuron. preganglionic fibres go strait in medulla directly dumps epinephrine and norepinephrine into bloodstream

why 2 neurons for autonomic but only 1 for somatic?

for sympathetic (fight/flight) you want one command spread to an entire system for speed... this is why its a quick response because its only 1 neuron