Histo On Histo On Your NervesYour Nerves

SSN HistologySSN Histology

October 26th, 2004October 26th, 2004

Missy Walker, maw2106@columbia.eduMissy Walker, maw2106@columbia.edu

So Young Kim, sk2298@columbia.eduSo Young Kim, sk2298@columbia.edu

Node of Ranvier

Perikaryon

Myelin-Producing Cell

So what’s in a nerve? So what’s in a nerve?

Axon Hillock

Dendrite

Axon Terminal

Axon

Nucleus of myelin-producing cells

Axon vs. DendriteAxon vs. Dendrite

Axon DendriteNONO Synthetic Synthetic Machinery! Machinery!

Nervous System ClassificationsNervous System Classifications

Nervous System

CNS PNS

Spinal Cord Cerebellum Cerebral Cx ANS Somatic Enteric (Ganglia) (Peripheral Nerve)

Spinal CordSpinal Cord

Spinal Cord: White MatterSpinal Cord: White Matter

Myelin Production in CNSMyelin Production in CNS

Oligodendrocytes

Spinal Cord Gray MatterSpinal Cord Gray Matter

Spinal CordSpinal Cord

Cajal’s Silver

MeningesMeninges

AstrocytesAstrocytes

No collagen in the CNS!!! No collagen in the CNS!!!

BrainBrain

CerebellumCerebellum

CerebellumCerebellum

Purkinje CellPurkinje Cell

Cerebral CortexCerebral Cortex

Cerebral CortexCerebral Cortex

Cerebellum vs. Cerebral CxCerebellum vs. Cerebral Cx

Cerebellum vs. Cerebral CortexCerebellum vs. Cerebral Cortex

Pyramidal Cells vs. Spinal Cord Gray Pyramidal Cells vs. Spinal Cord Gray MatterMatter

Peripheral Nervous System (PNS)Peripheral Nervous System (PNS) Nervous tissue outside of the brain and spinal cordNervous tissue outside of the brain and spinal cord

Somatic Nervous System

• Innervates skeletal muscle

• For conscious movement

• Cell bodies in CNS

Autonomic Nervous System

• Innervates smooth muscle and glands

• For organ function and regulation

• Cell bodies in CNS and PNS

Sympathetic & Parasympathetic

ANS - GangliaANS - Ganglia

Sympathetic GANGLIA in thorax contain:

• neuronal cell bodies

• satellite cells (support cells of the neuron)

Synapses occur

• Presynaptic fibers myelinated

• Postsynaptic fibers unmyelinated

Enteric NS - GangliaEnteric NS - Ganglia

Myenteric plexus in ENS

• Within Smooth Muscle of Gut

• NO Collagen (as in CNS)

• Glial cells (no Schwann cells)

• Nuclei are euchromatic

• Gut has “mind of its own”

ENS Ganglion vs ANS Ganglion ENS Ganglion vs ANS Ganglion

Cross section of nerveCross section of nerve

Organization by

Connective Tissues

• Endoneurium collagen fibers associated with individual neurons -Schwann cells within

• Perineurium layer(s) of connective tissue cells, create fascicles

• Epineurium dense cnxtive tissue binding fascicles into a bundle

Peripheral nervePeripheral nerve

• Epineurium

• Perineurium

• Endoneurium

Periph nerve Periph nerve - longitudinal section- longitudinal section

• Endoneurium• Perineurium• Epineurium

Longitudinal Section – Cajal stainLongitudinal Section – Cajal stain

Peripheral Nerve – High Power (Cajal)Peripheral Nerve – High Power (Cajal)

• Nodes of Ranvier• Neurilemma

(cytoplasm of Schwann cells)

• What’s the black?

Peripheral Nerve – High Power (H&E)Peripheral Nerve – High Power (H&E)

What’s the purple? What’s the white?

Cross Section – Peripheral NerveCross Section – Peripheral Nerve

• What’s the purple?

Peripheral NervePeripheral Nerve

• Why is this a Nerve, not a Ganglion?

Key Points for PNSKey Points for PNS• Ganglia

– Contain cell bodies for motor ANS

– Satellite cells are the supporting cell bodies (not glial, Schwann, or others of CNS)

• Peripheral Nerves

– Schwann cells make mylin sheath

– Node of Ranvier / saltatory conduction / Na channels

– Endoneurium around neurons, which form fascicles

– Perineurium around fascicles, which form bundles

– Epineurium around bundles

Same or different?Same or different?

Same or different?Same or different?

What are these?What are these?

Questions 1 & 2. . .

A

B

Question 3. . . Question 3. . .

Figure A Figure B

Question 4. . . Question 4. . .

Question 5. . . Question 5. . .

Question 6. . . Question 6. . .