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Final Exam

Terms in this set (31)

Somatic NS (voluntary)
Effector: skeletal m.

Efferent pathway: one neuron system

NT : Acetylcholine

Response: Excitatory
Autonomic NS (involuntary)
Effector: cardiac & smooth m., glands

Efferent pathway: two neuron systems - pre & post synaptic

NT: Pre = Acetylcholine.
Post = Varies between norepinephrine and epinephrine & parasympathetic acetylcholine

Response: Pre = Excitatory
Post = Either excitatory OR inhibitory
Sympathetic NS
Origin of presynaptic neuron body cell: thoracolumbar region of spinal cord (thoracolumbar division)

Fiber length: presynaptic = short
postsynaptic = long

Location of ganglia: close to spinal cord. Sympathetic chain. Prevertebral/collateral ganglia
Parasympathetic NS
Origin of presynaptic neuron cell body: Brain & sacral spinal (craniosacral division)

Fiber length: presynaptic = long
postsynaptic = short

Location of ganglia: in/near visceral effector organs
Parasympathetic NS
Only innervates internal organs. Inhibits or slows down body functions. Only major body function not inhibited is digestion
Where are the presynaptic neuron cell bodies located?
Nuclei for cranial nerves III, VII, IX, X.
S2 - S4 spinal cord levels
Where is the synapse between the pre- and post-synpaptic neurons?
Terminal ganglia :

Named ganglia (e.g. ciliary, pterygopalatine, submandibular & otic)

Intramural (near/in wall of effector organ)
Cranial outflow of the PNS
Presynaptic fibers run via:

Oculomotor n. (CN III) : smooth m. in eye

Facial n. (CN VII) : lacrimal, submandibular & sublingual glands

Glossopharyngeal n (CN IX) : parotid gland

Vagus n. (CN X) : almost every organ in thoracic & abdominal cavity, heart, lungs, liver, small intestine, pancreas, & proximal 1/2 of large intestine
Sacral outflow of CNS
Presynaptic neurons originate from S2-S4 level of spinal cord

Fibers or presynaptic neurons travel through ventral root --> spinal n. --> ventral rami

Exit ventral rami as pelvic splanchnic nn. Synapses in intramural ganglia (at/near effector organ)

Postsynaptic fibers innervate distal 1/2 large intestine & pelvic viscera (urinary bladder, ureters, & reproductive organs
Sympathetic NS
more widespread than parasympathetic. Speeds up or stimulates body functions. Only major body function not stimulated is digestion
Where are presynaptic neuron cell bodies located?
Thoracolumbar region of spinal cord (T1-L2). Intermediate horn
Where is the synapse between the pre and post synaptic neurons?
paravertebral ganglia (on sympathetic chain)

prevertebral/collateral ganglia (on abdominal aorta)
Sympathetic Chain (Trunk)
Located on both sides of vertebral column. Extends from cranial base to coccyx.

Paravertebral ganglia joined to spinal nn. by white and grey rami communicantes
White rami communicante
presynaptic fibers
only found at T1-L2 spinal cord levels
myelinated fibers
Grey rami communicante
postsynaptic fibers
found along all levels of spinal cord
unmyelinated fibers
Thoracolumbar outflow of the SNS
presynaptic fibers exit spinal cord through spinal cord through ventral root --> spinal nn. --> white ramus communicans --> paraverterbral ganglia on sympathetic chain
How many sympathetic pathways are there?
Three
Three Sympathetic pathways
1) synapse at paravertebral ganglia at same level

2) synapse at paravertebral ganglia at different level

3) does not synapse on chain (will synapse at a prevertebral/collateral ganglia on abdominal aorta
Snapse at paravertebral ganglia at same level
presynaptic fibers enter chain through white rami communicantes.

presynaptic fibers synapse with postsynaptic neuron at same level

postsynaptic fibers leave the chain through grey and rami communicantes & travel to the periphery & some viscera above the diaphragm
Snapse at paravertebral ganglia at different level
presynaptic fibers enter chain through white rami communicantes

presynaptic fibers ascend or descend on the chain and synapse with a postsynaptic neuron at a different level

postsynaptic fibers leave the chain through grey rami communicantes & travel to periphery & viscera above the diaphragm
Does not synapse on chain
preganglionic fibers enter chain through white rami communicantes (do not synapse on the sympathetic chain)

presynaptic fibers exit chain as splanchnic nerves. these nerves travel to and synapse on prevertebral/collateral ganglia on the aorta

postsynaptic fibers travel along blood vessels to viscera of the abdomen & pelvis
Adrenal Medulla
postsynaptic sympathetic neurons, located in the medulla of the adrenal gland, do not develop axons but still produce epinephrine and norepinephrine which will have sympathetic effects on target structures
Both visceral and somatic sensory fibers enter the spinal cord ____________
together
Referred pain
when visceral (sensory) pain radiates along somatic (motor) pathways

(heart attack and feeling pain in left arm)
Parietal layer
lines walls of cavity
Visceral layer
adheres to surface of organ
What does the small layer of serous fluid between the parietal & visceral layer do
reduces friction
Thorax
spans from the base of the neck to the diaphragm.
The thorax consists of
a wall, two pleural cavities, lungs, and the mediastinum
Thorax functions
houses and protects heart, lungs, and great vessels. conduit for structures passing from neck to abdomen. principal role in breathing. support for upper limbs
3 flat muscles found in each intercostal space that pass between the ribs
external intercostal, internal intercostal, and innermost intercostal.
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