Chapter 14 - Autonomic NS Flashcards
Autonomic NS is also known as the
visceral motor system
general functions of the autonomic NS
- motor system
- functions in homeostasis
- involuntary
- effectors: viscera, smooth muscle, cardiac muscle, and glands
- effects can be excitatory or inhibitory
compare and contrast sympathetic and parasympathetic nervous system: origin
sympathetic NS: thoracolumbar
parasympathetic NS: craniosacral
compare and contrast sympathetic and parasympathetic nervous system: function
sympathetic: fight or flight
parasympathetic: rest and digest
compare and contrast sympathetic and parasympathetic nervous system: preganglionic and postganglionic neuron lengths
sympathetic: short preganglionic neurons and long postganglionic neurons
parasympathetic: long preganglionic neurons and short postganglionic neurons
compare and contrast sympathetic and parasympathetic nervous system: ht, bp, digestion
sympathetic: increases ht and bp and decreases digestion
parasympathetic: decreases ht and bp and increases digestion
compare and contrast sympathetic and parasympathetic nervous system: pupil size
sympathetic: dilates pupil
parasympathetic: constricts pupil
compare and contrast sympathetic and parasympathetic nervous system: preganglionic neuron releases
both systems’ preganglionic neuron release ACh
compare and contrast sympathetic and parasympathetic nervous system: postganglionic neuron releases
sympathetic: releases ACh OR NE
parasympathetic: only releases ACh
compare and contrast the autonomic NS and the somatic motor division: type of control
autonomic: involuntary
somatic motor: voluntary
compare and contrast the autonomic NS and the somatic motor division: effector organs
autonomic NS: smooth muscle, cardiac muscle, glands
somatic: skeletal muscle
compare and contrast the autonomic NS and the somatic motor division: number of neurons to innervate the muscles and glands
autonomic: 2
somatic motor: 1
compare and contrast the autonomic NS and the somatic motor division: sensory input
autonomic: internal sensory input
somatic: sensory input from external environment
compare and contrast the autonomic NS and the somatic motor division: response of the effector
autonomic: involuntary and automatic
somatic motor: voluntary and consciously controlled
compare and contrast the autonomic NS and the somatic motor division: NT released
autonomic: ACh / NE
somatic: ACh
preganglionic neuron
- has cell body in the CNS
- lightly myelinated axon extending outwards into the PNS
postganglionic neuron
- has cell body in the PNS
- stimulated by ACh released by preganglionic neuron
- extends to effector organ
- NONMYELINATED
- stimulates effector organ by releasing ACh or NE at axon terminal
ACh can be inhibitory or excitatory. How?
depends on the receptor
there are different receptors for ACh
what is dual innervation?
organs that are affected by both the parasympathetic and sympathetic fibers
ex: one division activates something while the other tends to depress it
dual innervation example: heart rate
parasympathetic vagus nerve decreases ht
sympathetic cardiac nerves increase ht and force of contraction
which organs lack dual innervation?
skin
adrenal gland
arterioles
only innervated by sympathetic NS
compare and contrast sympathetic and parasympathetic nervous system: ganglion location
sympathetic: close to the vertebral column (sympathetic trunk)
parasymp: close to or w/in effector organ
adrenal medulla
- has direct synapsing
- aka has no postganglionic neuron
- direct synapsing bc its quicker —> we need adrenaline quickly when in danger
- releases EPI or NE into the blood when stimulated
control of ANS
cerebral cortex —> limbic system —> hypothalamus —>brain stem —> spinal cord
NTs and receptors of the ANS
NTs: ACh and NE
receptors: cholinergic (binds to ACh) & adrenergic (binds to EPI or NE
cholinergic receptors
nicotinic receptors and muscarinic receptors
cholinergic receptor: nicotinic
- ligand-gated sodium channels
- triggers depolarization on target cells
- excitatory
- locations: All ANS ganglionic synapses and somatic motor end plates
cholinergic receptor: muscarinic
- 5 types
- some open ligand-gated K channels —> triggers hyperpolarization and is inhibitory
- others are excitatory
- locations: parasympathetic synapses w/ effectors and sympathetic synapses w/ effectors
5 types of adrenergic receptors
alpha 1
beta 1
alpha 2
beta 2
remember that 1s are excitatory and 2 are inhibitory
alpha 1
- smooth muscles (arterioles)
- open sodium channels
- excitatory
beta 1
- cardiac tissue only
- open sodium and calcium channels
- excitatory
alpha 2
- smooth muscle (digestive tract)
- open k channels
- inhibitory (mostly)
beta 2
- smooth muscles (bronchioles and some arterioles)
- open k channels
- inhibitory
autonomic agonist and antagonists
- ACh
- EPI and NE
- atropine
- beta-blockers
autonomic agonists and antagonists: ACh
- muscarinic receptors on heart
- effect: decrease ht
autonomic agonists and antagonists: Atropine
- antagonist for muscarinic receptors
- effect: inhibits ACh binding to receptors —-> inc ht
autonomic agonists and antagonists: EPI and NE
- beta 1 receptors on heart
- effect: inc ht and in force of contraction
autonomic agonists and antagonists: beta-blockers
- antagonist for beta 1 receptors
- effect: inhibits EPI and NE binding to receptors —> Ht decs. bp decs.
