Peripheral Nervous System Flashcards
what are the two main branches of the nervous system?
- central nervous system
2. peripheral nervous system
ganglion
collection of nerve cell bodies in the PNS
what structures are included in the PNS?
- spinal nerves and their associate ganglia
- cranial nerves and their associated ganglia
- enteric nervous system (w/i gut)
what are the two types of neuronal cell morphologies present in the human body?
- multipolar
2. pseudounipolar
what are the main structural components of a multipolar neuron?
- axon
- body
- dendrites
what are the main structural components of a pseudounipolar neuron?
- cell body
2. axon
multipolar neruon
efferent neuron, signal travels away from cell body
pseudounipolar neuron
afferent (AKA sensory) neuron, signal travels toward cell body
where are multipolar neurons found?
- cell bodies are ventral gray horn of the spinal cord
2. ganglia in periphery
where are pseudounipolar neurons found?
dorsal root ganglia
what are the two functional divisions of the peripheral nervous system?
- somatic nervous system
2. visceral nervous system
what is a similarity between the somatic and visceral nervous divisions of the PNS?
have both afferent and efferent neurons (multipolar and pseudounipolar)
what 4 types of tissues are innervated by the somatic division of the PNS?
body wall and limbs:
- skin (everything except blood vessels and sweat glands)
- muscle (skeletal)
- bone (periosteum)
- joints (fibrous portions of capsules)
what 7 types of tissues/structures are innervated by the visceral division of the PNS?
contents of body cavities, blood vessels, everywhere:
- smooth muscle
- cardiac muscle
- lungs
- exocrine and endocrine glands
- contents of body cavities
- blood vessels
- glands
what are the 3 different types of muscles, what division of the PNS innervates them?
skeletal: somatic
cardiac: visceral
smooth: visceral
what are the similarities between the afferent somatic and afferent visceral divisions of the PNS?
- cell body (pseudounipolar) located in spinal ganglion (dorsal root ganglion)
- central axon innervates neurons in CNS
what distinguishes the afferent somatic and afferent visceral divisions of the PNS?
- somatic: conveys touch, vibration, temp, proprioception, somatic pain (highly localized pain)
- visceral: peripheral axon innervates viscera, conveys visceral pain (poorly localized) and other visceral sensations
what distinguishes the efferent somatic and efferent visceral divisions of the PNS?
- somatic: cell body (LARGE, multipolar), located in CNS, axon directly innervates skeletal muscle
- visceral: cell body (SMALL, multipolar), located in CNS communicates with second neuron (SMALL, multipolar), that innervates visceral tissue
where do the somatic afferent neurons enter the gray matter of the spinal cord?
dorsal root
where to the somatic efferent neurons enter the gray matter of the spinal cord?
ventral root
where do the somatic afferent and efferent neurons come together lateral to the spinal cord?
ventral ramus
where do the the visceral afferent neurons enter the gray matter of the spinal cord?
dorsal root
where to the visceral efferent neurons enter the gray matter of the spinal cord?
ventral root
where are the cell bodies of the somatic efferent nervous system found in the spinal cord?
ventral horn of the gray matter
where are the cell bodies of the visceral efferent nervous system found in the spinal cord?
intermediolateral cell column and in peripheral ganglia (because there are 2)
which division of the PNS always has two neurons that work together to relay a signal?
visceral efferent
dermatome
patch of skin innervated by somatic sensory neurons found in a particular DRG (dorsal root ganglion)
myotome
group of muscles innervated by the somatic motor neurons whose axons exit the spinal cord in a particular spinal nerve
nerve plexus
portions of the ventral rami of the peripheral nerves where axons redistribute in order to carry signals to appropriate location
name the 4 plexuses in the body
- cervical nerve plexus (C1-C4)
- brachial nerve plexus (C5-T1)
- lumbar nerve plexus (L1-L4)
- sacral nerve plexus (L4-S4)
radiculopathy
damage to spinal nerve, would manifest as issue w/ sensory and neuron function
mononeuropathy
damage to peripheral nerve that would manifest as an issue w/ either sensory and neuron function of that nerves
conus medullaris
inferior portion of the spinal cord (may terminate between T12 and L3)
cervical enlargement
extends from C4 through T1, associated with the brachial plexus
lumbosacral elnargement
extends from L2 through S3, associated with the lumbar and sacral plexuses
lumbar cistern/subarachnoid space
area that contains the cauda equina
number of pairs of spinal nerves
31
cervical: 8
thoracic: 12
lumbar: 5
sacral: 5
coccygeal: 1
what structures make up the CNS?
brain, spinal cord
what structures make up the PNS?
nerve fibers and cell bodies
name the meninges that surround the spinal cord from deep to superficial
- dura mater
- arachnoid
- pia mater
where is CSF found in the meninges surrounding the spinal cord?
subarachnoid space (between arachnoid and pia mater)
discuss the two spinal enlargements and where they are found
- cervical enlargement (around C5)
2. lumbar enlargement (around L12)
where at what level does the conus medullaris usually fall w/i the vertebral column?
around L1
what are the specialized structures derived from the pia mater?
- filum terminale internum
2. denticulate ligament
filum terminale
structures that lies among the cauda equina, derived from pia mater at base of conus medullaris.
