ANS Flashcards
functions of the ANS
maintain homeostasis, activate emergency mechanism, housekeeping
sympathetic
fight or flight
parasympathetic
rest and digest
enteric
gut
divisions of the ANS
sympathetic, parasympathetic, enteric
afferent neurons
relay sensory info to the CNS
efferent neurons
relay motor commands from the CNS to target tissues
efferent neurons of the ANS
2 neuron chain connected by a ganglion , multiple targets, excitatory and inhibitory effects (ganglion = cluster of neuron cell bodies outside the CNS)
preganglionic fiber
myelinated
postganglionic fiber
unmyelinated
effector organs of the ANS
smooth muscle, cardiac muscle, glands
PSN neuron
long preganlionic fiber, short postganglionic fiber
SNS neuron
short preganglionic fiber, long postganglionic fiber
PSN cell body locations
Cranial and sacral
SNS cell body locations
thoracic and lumber
sympathetic truck
chain of synaptic Ganglia
neural pathways in the Sympathetic NS (3)
- synapse immediately with postgaglionic neuron in sympathetic ganglion
- travel up or down the chain and synapse in Ganglia at other levels
- pass through chain without synapsing, continue to collateral ganglion as splanchnic nerves
communicating “rami”
two branches which connect a paravertebral ganglion to a spinal nerve (white and grey)
ascend or descend
travel up or down the chain and synapse in gnaglia at other levels
splanchnic (pre or post)
pass through without synapsing and continue to collateral ganglion
synapse immediately
synapse immediatly with post ganglionic neuron in sympathetic ganglion
fight or flight responses
think of table and dog example
adrenal medulla
secrets epinephrine (80) and norepinephrine (20)
terminal ganglion
a parasympathetic ganglion situated on or close to a inverted organ, the site where preganglionic nerve fibers terminate
parasympathetic neural pathway
travel preganglionic fiber, to post synaptic ganglion, synapse, and travel post ganglionic fiber, to effector organ
rest and digest response
think of table - restful state watching movie having popcorn
autonomic tone
background levels of activity maintained by both sympathetic and parasympathetic divisions
activated reciprocally
activation of one decreases activation of other
dual innervation
most organs receive input form both SNS and PNS (exceptions: adrenal medulla, blood vessels (most), swear glands, = only sympathetic
antagonitstic effects
sympathetic and parasympathetic do the opposite (SNS increases heart rate, PNS decreases heart rate)
cooperative effect
SNS and PNS do the same thing, change the type and volume of salivia produced
varicosity
chain of swelling along the branches of postganglionic fiber, contains synaptic vessels
cholinergic receptors
bind ACh
adrenergic receptors
bind NE/E
Structure of nicotinic receptors (cholinerrgic)
ionotropic. binding of ACh causes confimational change
Muscarinic (cholinergic) and adrenergic receptors structure
metabotropic. binging produces repsponse through G-coupled mechnism
convergence
large number of presynaptic neurons form synapses with a single postsynaptic neuron (coming together)
divergance
small number of presynaptic neurons form synapses with a large number of postsynaptic neruons (spread out)
sympathetic and parasympathetic (convergance and divergance)
SNS - greater degree of divergance (diffuse)
PNS - specific
spinal cord
integrates autonomic reflexes
medulla
major ANS reflex centers
hypothalamus
integration and command center for autonomic functions
