ANS Ch 16 Flashcards
ANS
System of motor neurons that innervates smooth and cardiac muscles and glands. Also called involuntary or visceral motor system.
Two neuron chain
ANS uses two neurons to reach the effector unlike the CNS that uses only one
Preganglionic neuron
First neuron whose body lies lies within the brain or spinal cord, it synapses with the second motor neuron.
Post ganglioninc neuron
Second motor neuron whose cell body is within the autonomic ganglion outside the CNS.
2 autonomic neurotransmitters
Acetylcholine
Epi and Nor Epi
Autonomic postganglionic fibers release?
Epi and Nor Epi
Secreted by most sympathetic fibers
Parasympathetic fibers release
ACh
Dual Innervation
Two divisions of the ANS–sympathetic and parasympathetic–balance each other out
Some organs only receive sympathetic stimulation but vital organs have both.
Parasympathetic
Rest and digest:
Craniosacral: originate in brain and sacrum
Long preganglion short post ganglion fibers
Ganglion are close to organ served
Sympathetic
Fight or flight:
Thoracolumbar: originate in thoracic and lumbar
Short preganglion and long post ganglion fibers
Ganglion are close to spinal cord
Cranial Part
Oculomotor (III)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)
Oculomotor nerve
Innervated the smooth muscles of the eye that causes the pupil to constrict and lens to bulge. Synapse in the ciliary ganglia
Facial nerves
Activate nasal glands and lacrimal glands: pterygopalatine ganglia
Stimulate sublingual salivary glands: submandibular ganglia
Glossopharyngeal nerves
Synapse in the otic ganglia. Activate parotid salivary glands anterior to the ears
Vagus Nerve
Account for 75% or preganglionic parasympathetic fibers and innervate virtually every thoracic and abdominal oregan
Sacral Part
Serves pelvic organs and distal half of the intestines. S1-S4 forn the pelvic splanchnic nerves.
Sympathetic Division
Arise from T1 - L2,
Thoracolumbar division
3 locations of sympathetic ganglionic neurons
Sympathetic chain ganglia (paravertebral) Collateral ganglia (prevertebral) Adrenal medulla (release neurotransmitters into the blood stream)