Sf Unit 2 Somatic Ns, Autonomic Ns, Ns Histology

Front 1

What are some key differences between sensory and somatomotor neurons?

Back 1

Sensory neurons: pseudounipolar, myelinated dendrites
Somatomotor neurons: many dendrites, single axon, cell bodies located in ventral horn of spinal cord

Front 2

Where are the cell bodies and cell processes located in the peripheral nervous system? Central nervous system?

Back 2

PNS: cell bodies-->ganglia; cell processes-->nerves
CNS: cell bodies-->gray matter; cell processes-->white matter (tracts)

Front 3

Describe the process of secondary neurulation and what the caudal eminence is

Back 3

Secondary neurulation is process where caudal eminence (mesoderm) attaches itself to base of neural tube, forming spinal segments, meninges, filum terminale and somites

Front 4

What is tethered cord syndrome?

Back 4

Occurs when caudal eminence anchors spinal cord at a lower level than normal

Front 5

The neural tube gives rise to what neural tissues? How about the neural crest?

Back 5

Neural tube- brain, spinal cord, somatomotor neurons, and preganglionic autonomic neurons
Neural crest- all ganglia and peripheral sensory neurons (and melanocytes)

Front 6

Dorsal and ventral spinal rami contain what types of neurons?

Back 6

Somatomotor neurons, general sensory neurons, and sympathetic neurons

Front 7

Cutaneous branches from dorsal and ventral rami contain what types of neurons?

Back 7

general sensory neurons and sympathetic neurons

Front 8

What is a dermatone?

Back 8

area of skin supplied by a pair of spinal nerves

Front 9

Describe briefly the cadua equina, the conus medularis, and the filum terminale

Back 9

cadua equina- collection of dorsal/ventral roots that extend passed end of spinal cord and exit proper intervertebral foramen
conus medularis- tapering end of spinal cord
filum terminale- filament of pia anchoring spinal cord, extends passed termination of spinal cord

Front 10

In general terms, where are the neurons of the sympathetic and parasympathetic nervous systems found?

Back 10

Sympathetic: throughout the body
Parasympathetic: head, neck, and body cavities

Front 11

Trace the path of sympathetic neurons from spinal cord to body wall or thoracic viscera

Back 11

Lateral horn of spinal cord--> ventral roots between T1-L2--> spinal nerve--> white rami communicans-->sympathetic trunk (synapse)--> gray rami communicans--> dorsal/ventral rami for body wall or cardiopulmonary splanchnic nerves for thoracic viscera

Front 12

Trace the path of sympathetic neurons from spinal cord to abdominal and pelvic viscera

Back 12

lateral horn of spinal cord--> ventral roots of T1-L2--> spinal nerve--> white rami communicans--> sympathetic trunk--> thoracic and lumbar splanchnic nerves--> collateral ganglia (synapse)--> abdominal and pelvic viscera

Front 13

How do parasympathetics reach the thoracic and abdominal viscera?

Back 13

Leave CNS through vagus nerve, which synapses in ganglia that are very close to innervating organs (eyes, heart, lungs, stomach, small intestine)

Front 14

How do parasympathetics reach the pelvic and hind gut viscera?

Back 14

Ventral rami of S2-S4 carry pelvic splanchnic nerves, which synapse in ganglia very close to innervating organs (part of large intestine, urinary bladder, genital tissues)

Front 15

What neurons appear in an autonomic plexus?

Back 15

visceral sensory fibers, presynaptic parasympathetics, and post and presynaptic sympathetics

Front 16

General sensory neurons: intensity of sensation, general location, tissue origin, location of cell body

Back 16

strong intensity, innervates body wall, originates from somatopleure, cell body in dorsal root ganglia

Front 17

Visceral sensory neurons: intensity of sensation, general location, tissue origin, pathway of neurons

Back 17

dull sensation, innervates visceral organs, originates from splanchnopleure, travel via autonomic pathways in the gut (vagus and splanchnic nerves)

Front 18

What are the three connective tissue layers of a nerve, and where are they located?

Back 18

Epineurium- around entire nerve
perineurium- separate nerve fasicles
endoneurium- surround neurons

Front 19

Provide properties of perineurial cells

Back 19

secrete collagen, have tight junctions, have actin and contractile properties

Front 20

In a neuron, what are the perikaryon and neuropil

Back 20

perikaryon- cell body
neuropil- intercellular matrix

Front 21

Difference between Golgi type I neurons and Golgi type II neurons

Back 21

Golgi type I neurons pass out and through tissues
Golgi type II neurons remain in local tissue

Front 22

What are Nissl bodies and describe their location within the neuron

Back 22

Nissl bodies are ribosomes
They are located in the cell body (perikaryon) and dendrites, but not in the axon or axon hillock

Front 23

EM cross section of axon will likely show what features

Back 23

neurilemma- sheath of Schwann cell
Myelin (if axon is myelinated)
microtubules and neurofilaments in the interior of the axon

Front 24

What is the axolemma?

Back 24

innermost membrane around axon

Front 25

Explain the process of myelination and what Schmidt-Lanterman clefts are

Back 25

axon recruits Schwann cell, which wraps itself tightly around axon, forming concentric layers of electron dense cytoplasm and light extracellular space
S-L clefts are portions of cytoplasm that are squeezed between myelin during myelination

Front 26

What are the support cells of the PNS?

Back 26

Schwann cells, satellite cells (surround cell bodies)

Front 27

What are the support cells of the CNS?

Back 27

oligodendrocytes, astrocytes (provide nutrients, help form blood-brain barrier, microglia (phagocytotic)

Front 28

Describe the process of nerve repair

Back 28

distal end of cut axon dies; proximal end grows and branches; if one branch penetrates existing Schwann cell sheath, neuron will grow back and sensation/muscle function is restored