autonomic nervous system Flashcards
somatic nervous system
part of the nervous system that innervates skeletal (voluntary) muscle
- motor system
autonomic nervous system
part of nervous system that innervates smooth muscle, cardiac muscle, and secretory glands (sweat, digestive)
what kind of movement is the autonomic nervous system responsible for?
involuntary
what does the autonomic nervous system do?
stabilize the internal environment (homeostasis)
another name for ANS
visceral motor system
what transmitter is at neuromuscular junction?
Acetylcholine
synapse with skeletal muscle
- motor neuron attaches to muscle via motor end plate
- formation of neuromuscular junction
- regular neuron signaling
synapse with smooth muscle
- autonomic nerve over smooth muscle
- synaptic cleft is larger
- does not actually attach with anything
- neurotransmitter is released into synaptic cleft “en passant” (in passing)
- less pressure, more diffusion
preganglionic neurons are
- myelinated
- B fiber (not alpha motor neurons)
- cholinergic (use acetylcholine as transmitter)
postganglionic neurons
- unmyelinated
- C fiber (unmyelinated - Schwann cells don’t wrap around)
- cholinergic or noradrenergic (neurotransmitters = acetylcholine, noradrenaline, or norepinephrine)
divisions of the autonomic nervous system
- sympathetic
- parasympathetic
characteristics of the sympathetic nervous system
- thoraco-lumbar (T1-L2) nerves
- utilizes energy in an emotion, high energy situation (inc. heart rate)
- noradrenergic
- short pre-ganglions (near spinal cord)
- long post-ganglionic
- capable of diffuse discharge (mass discharge - fight or flight)
- full activation at once
characteristics of the parasympathetic nervous system
- cranio-sacral
- energy conservation (digestive, glands, relaxation)
- cholinergic
- long pre-ganglions
- short post-ganglions
- discrete discharge (not connected, individual)
why are sweat glands an exception to sympathetic and parasympathetic pathways?
they utilized cholinergic (instead of noradrenergic) sympathetics
in general how does the enteric nervous system work?
- sensory fibers
- motor neurons stimulate muscles, glands, network of ganglia
- influence by sympathetic and parasympathetic NS
enteric nervous system is located where?
in walls of GI tract
enteric nervous system innervates what?
smooth muscle and glands of GI tract
what is the enteric nervous system?
a division of the autonomic nervous system that has its own reflex circuits (NS for the guts)
- there are as many neurons in the gut as there are in the spinal cord
function of the enteric nervous system
- regulate motility and secretion in the GI tract
- receive inputs from the sympathetic and parasympathetic divisions
patterns of discharge
- tonic discharge
- mass discharge
what does the ANS maintain?
blood pressure and body temperature
adrenal medulla is part of
sympathetic NS
effects of adrenal medullary hormones
- increase blood glucose
- mobilization of fat
- increased alertness
types of interactions between sympathetic and parasympathetic NS
- antagonistic interactions
- cooperative interactions
- single innervation
