Autonomic Nervous System Flashcards
What is another name for the ANS?
General Visceral Efferent nerves
True or False: ANS is essential for the function of the effector organ and is not regulatory in function?
False; it is NOT essential for function and IS regulatory
Where does the ANS extend to and from?
It extends from the CNS to the smooth m., cardiac m., and glands
How many neuron chains does the ANS have?
2 and they link the CNS to the autonomic effector
What structures influence the ANS?
Spinal cord, Brain stem, hypothalamus
What are ganglia?
Nerve cell bodies outside of the CNS
What are nuclei?
Neuron cell bodies inside the CNS
What are 3 characteristics that describe the general somatic efferent neurons?
1) voluntary
2) have one neuron between CNS & effector
3) target effector is skeletal m.
What are the general somatic afferent neurons?
General sensory neurons in the skin, bones, muscle, and joints that convey impulses from dorsal root fibers to CNS
What are the general somatic efferent motor neurons?
Neurons that use impulses from the CNS that travel through ventral root fibers and cause skeletal m. Contraction
What is the origin location of the sympathetic nervous system?
Thoracolumbar
What is the origin location of the parasympathetic nervous system?
Cranial-Sacral
What does the sympathetic nervous system supply?
Glands, smooth muscles of skin, thoracic/pelvic/abdominal viscera, salivary glands, nasal cavities, iris, blood vessels, adrenal medulla
Synapse location for sympathetic ns?
Paravertebral or prevertebral ganglion
Synapse location for parasympathetic ns?
Wall of effector organ
What are preganglionic fibers in the ANS?
First neuron from CNS; Myelinated
Are postganglionic fibers in the ANS myelinated?
No
What length are the preganglionic fibers in the sympathetic ANS?
Short
What neurotransmitter is secreted at the preganglionic synapse in the ANS?
Acetylcholine
What is the length of the postganglionic sympathetic ANS nerve fibers?
Long
What neurotransmitter is secreted at the postganglionic fiber synapse in ANS?
Norepinephrine
Name all 3 paravertebral ganglia in the ANS?
Cranial Cervical, Middle Cervical, Cervicothoracic
Name all 6 prevertebral ganglia in the ANS?
Cranial mesenteric, caudal mesenteric, gonadal, renal, celiac, and pelvic ganglia in plexus
What structures does the cervicothoracic ganglion serve?
The thoracic viscera
What structures does the cranial cervical ganglion serve?
Head and neck
What structures does the middle cervical ganglion serve?
Heart and lungs
What structures does the cranial mesenteric, caudal mesenteric, renal, gonadal, and celiac ganglia serve?
The abdominal and pelvic viscera
General presynaptic pathway for ANS?
Ventral root, spinal nerve, ramus communicans, sympathetic trunk, ganglion, effector organ
Head region sympathetic pathway
1-Ventral root
2-spinal nerve,
3-ramus communicans,
4-sympathetic trunk,
5-ansa subclavia,
6-cervical sympathetic trunk
7-cranial cervical ganglion
8- plexuses run with internal and external carotid arteries
9- target organ
Head region of ANS synapse?
Cranial Cervical ganglion
Head region of ANS post-synapse pathway
Nerve plexuses on external and internal carotid arteries that run to target effectors
Pre-synaptic path. for neck region of ANS
1- ventral root
2- spinal nerve
3- ramus communicans
4- sympathetic trunk
Synapse for neck region of ANS?
Cervicothoracic ganglion
Post-synaptic pathway for neck region
1- vertebral nerve
2-rami communicans
3- cervical spinal nerve
4- dorsal/ventral branches to smooth muscles and skin
Pre-synaptic pathway for body wall and limbs (ANS)
Ventral root, spinal nerve, ramus communicans, sympathetic trunk
Synapse for body wall and limbs (ANS)
Sympathetic trunk ganglia (paravertebral ganglia- cranial cervical, middle cervical, cervicothoracic ganglia)
Post-synaptic pathway for body wall and limbs (ANS)
1-rami communicans
2-spinal nerve
3- dorsal/ventral branches to smooth muscle and skin
Pre-synaptic pathway for thoracic viscera (ANS)
1- Ventral root
2– spinal nerve
3- ramus communicans
4- sympathetic trunk
Synapses for thoracic viscera (ANS)
Cervicothoracic and middle cervical ganglia
Post-synaptic pathway for thoracic viscera (ANS)
Cardiosympathetic nerves from ansa subclavia
Pre-synaptic pathway for abdominal viscera (ANS)
1-Ventral root
2- spinal nerve
3-ramus communicans
4- sympathetic trunk
Synapses for abdominal viscera (ANS)
Left/right celiac ganglia, cranial/caudal mesenteric ganglia, renal ganglion, gonadal ganglion
Post-synaptic pathway for abdominal viscera (ANS)
Nerve plexuses on abdominal artery
Pre-synaptic pathway for pelvic viscera (ANS)
1-Ventral root
2-spinal nerve
3-ramus communicans
4- sympathetic trunk
5- lumbar splanchnic nerve
6- caudal mesenteric ganglion
Synapse for pelvic viscera (ANS)
Caudal mesenteric ganglion
Post-ganglionic pathway for pelvic viscera (ANS)
1-Hypogastric nerve
2- pelvic plexus; branches to pelvic viscera
Which cranial nerves are associated with the brain stem nuclei in the PNS?
III, X, IX, VII
Which segments of the sacral spinal cord are associated with the PNS?
Segments 1-3
Name of CN III
Oculomotor
Name of CN VII
Facial n.
Name of CN IX
Glossopharyngeal n.
Name of CN X?
Vagus n.
Length of preganglionic fibers in PNS?
Long
Length of postganglionic fibers of PNS?
Short
What neurotransmitter is at both synapses in PNS?
ACETYLCHOLINE
What are the only blood vessels that the PNS supply?
Penile arteries
The PNS does NOT supply…
Skin, sweat glands, piloerector muscles, or cutaneous blood vessels, nor the adrenal medulla
Vagus nerve supplies…
Thoracic & abdomina viscera
What happens to the vagosympathetic trunk at the middle cervical ganglia?
It splits from vagosympathetic trunk to run by itself as the vagus nerve
Left recurrent laryngeal nerve leaves…
Around aortic arch
Right recurrent laryngeal nerve leaves around…
Right subclavian artery
Pre-synaptic pathway for PNS?
Ventral branch of S1-S3
PNS Synapse
Pelvic ganglia at pelvic plexus
Cholinergic fibers include…
1-Preganglionic fibers from ANS and PNS
2- Postganglionic fibers from PNS only
Sympathomimetic drugs are…
Drugs that mimic the sympathetic system at the neuroeffector junction
Parasympathomimetic drugs are…
Drugs that mimic the PNS at the neuroeffector junction
What do drugs that have a nicotinic effect do?
Stimulate the 2nd neurons of the sympathetic and parasympathetic ns
What type of drugs act on alpha and beta receptors?
Sympathetic
How do effectors with alpha receptor respond?
Contract smooth muscles (increase BP)
How do effectors with beta receptors respond?
Relaxation of smooth, blood vessel muscles that supply the heart
Preganglionic pathway to dilator muscle of the iris
1-neuronal cell bodies at T1-T3
2-rami communicans
3- thoracic sympathetic trunk
4- cervical sympathetic trunk
Synapse of dilator muscle of the iris?
Cranial cervical ganglion
Postganglionic pathway for dilator muscle of the iris
Fibers of the internal carotid artery that end at dilator muscle of iris
Horner’s Syndrome is…
When the nervous pathway to the dilator muscle of the iris is interrupted
Signs of horner’s syndrome are…
C6-T2 (brachial plexus) avulsion, loss of sympathetic innervation of eye, enopthalmus, protrusion of 3rd eyelid, miosis, ptosis
