Nerve Tissue- Lecture 9/23/21 Flashcards
Neurons
Nerve cells
Afferent
Taking something in towards the cell body
Efferent
Out towards the destination
Single neuron pathways
Sensory and motor nerves
Axon hillock
Region between cell body and axon where action potential is initiated
Dendrites
Many per motor neuron, sensory neurons do not have any
Motor neuron location
Ventral horn
Sensory nerve cell body location
Dorsal root ganglion
Two neuron systems
Autonomic motor nerves, one cell body in CNS and one in peripheral ganglia
Endoneurium
Connective tissues surrounding each individual nerve
Perineurium
Surrounds fascicles of nerves, form blood nerve barrier
Epineurium
Surrounds the nerve
Peripheral nerve appearance in longitudinal section
Appears to be wavy
Schwann cells
Surround every axon, myelinates motor and sensory, does not myelinate autonomic
Myelin sheath
Surrounds motor and sensory axons, with the Schwann cell membrane
Pseudounipolar neurons
Have one axon that splits to different directions
Example of pseudounipolar neurons
Sensory nerves
Bipolar neurons
Have one long dendrites and one long axon
Examples of bipolar neurons
Sensory nerves and sensory organs, specifically olfactory and retina
Multipolar nerves
One long axon and many dendrites coming off of it
Examples of multipolar nerves
Somatic motor and visceral motoe
Location of sensory nerve cell body
Dorsal root ganglia
Blood-nerve barrier
Created by the perineurium, have tight junctions and gap junctions to restrict entry of leukocytes
Neurolemma
Schwann cell cytoplasm
Neurokeratin
Residual protein components in the myelin sheath following lipid extraction
Nodes of Ranvier
Area in between Schwann cells, lots of Na+ channels,
Saltatory conduction
Signal transduction in neurons that “hop” from one node of ranvier to the next
Schmidt-Lanterman incisures
Vertical spaces in the myelin that allow for communication
Ganglia
Clusters of neuron cell bodies in the PNS
How to tell between sensory and autonomic ganglia
Sensory: Central nucleus with ring of satellite cells completely surrounding it
Autonomic: Eccentric nucleus with dispersed satellite cells
Enteric ganglia
Enteric plexus that can either be submucosa or surmucosa