Classifications of the PNS (Quiz 5) Flashcards
Are there nerves in the CNS?
no
more myelin = ___________ transduction
faster
define nerve
bundle of axons
What does somatic refer to?
-cells of the body
-somatic branch of the NS innervates the body wall
-includes skin, bone, blood, and skeletal muscle
Somatic branches develop from what?
ectoderm and mesoderm
What does visceral refer to?
-organs, guts, internal membranes/tubes
-tunica media, all organs and related smooth m.
What is viscera formed from?
endoderm
Is viscera voluntary or involuntary?
involuntary (unconsciously aware)
T/F: all spinal nerves are mixed nerves
true
A connective tissue sheath- the _____________ surrounds each nerve. Each bundle of nerve fibers is called a fasciculus and is surrounded by a layer of connective tissue called the _______________. Blood vessels are associated with each fascicle
epineurium, perineurium
Individual axons are surrounded by loose connective tissue called the….
endoneurium
What does it mean if a nerve is general?
-has pathways and receptors
-distributed throughout body
-no specific modality, threshold, or info transmitted
What does it mean if a nerve is special?
-receptors and related axons, and pathways are from specific structures
there are 3 types:
1) unique anatomical structures
2) different modalities and detection mechanisms than general nerves
3) developmentally special
What are the 3 classifications of the PNS?
1) general or special
2) somatic or visceral
3) afferent or efferent (direction)
What does afferent mean?
-going in
-info goes from PNS into CNS
-input goes to brainstem or spinal cord
-sensory info
What does efferent mean?
-going out
-info goes from CNS to PNS
-goes from CNS to target tissue
-motor info
Both efferent and afferent are used to describe direction of….
nerves (bundles of axons in PNS)
What is the function of GSA?
-all spinal nerves contain GSA
-general sensation on pain, temp, light touch, pressure, vibration, proprioception
-receptors are thermal, nociceptors and mechanoreceptors
-innervates skin
What is the function of GVA?
-input from visceral/internal organs, glands, or blood vessels
-often pain or reflex info
What is the function of GSE?
-info comes from large ventral horn neurons
-info goes to skeletal m. in body wall and extremities
-found all throughout spinal cord
What is another name for GSE?
LMNs
What is the function of GVE?
-preganglionic neurons that form the ANS
-sympathetic from T1-L4
-parasympathetic from S1-S4 and all CNs
-info goes out to smooth m. tubes or glands
What is the function of SVE?
-motor innervation to muscles of the pharyngeal arches/ brachial arches (this is developmentally special, info goes to voluntary striated muscles of the larynx and pharynx), muscles of mastication, and facial expression
-anything motor with swallowing, breathing, talking, etc
note: this is visceral bc its the start of GI tube, thats why its not somatic
What is the function of SVA?
-sensory fibers that develop in association with the GI tract
-carry olfaction and gustation info
-taste via CN VII and IX
What is the function of SSA?
-special receptors for vision, hearing, and balance
-CN II and VIII
-no spinal nerves are involved here, just CN II and VIII
Which nerve classification will feel that the fire is hot?
GSA
Which nerve classification will have a sensation to urinate?
GVA
Which nerve classification will move your apple pencil across ipad?
GSE
Which nerve classification will taste your cup has tea in it?
SVA
Which nerve classification will swallow your tea?
SVE
Which nerve classification will detect heartburn or gastric fullness?
GVA
Which nerve classification will smell a classmates perfume?
SVA
Which nerve classification will feel a tickle from an ant running up your leg?
GSA
Which nerve classification allows for chewing a piece of gum?
SVE
Which nerve classification sees Dr. Attaway walk across the room?
SSA
Which nerve classification sends a message to increase digestive motility?
GVE
Which nerve classification has the smooth muscle of arterial walls contract?
GVE
Which nerve classification allows you to stand to change seat?
GSE
