Transcript Laboratory 9

Lab 9
Histology and Gross
Anatomy of the
Nervous System
Lab 9 Activities
1. Identify neuron, pyramidal cell, Purkinje
cell, and peripheral nerve slides
2. Identify boldfaced structures on brain
models
3. Identify specified parts in lab manual on
sheep brain dissection
4. Identify cranial nerves (by name + number
I - XII)
Parts of a Neuron
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Soma
Dendrites
Axon
Cell Body (Soma)
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Contains the usual cellular organelles
Primary site of synthesis & metabolism
Cell membrane contains receptors to respond to stimuli
Cell membrane transmits graded potentials
Most cell bodies are located within the CNS
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clusters of neuron cell bodies in the CNS are called nuclei
clusters of neuron cell bodies in the PNS are called ganglia
Dendrites
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Short, tapering, highly branched
processes
Not myelinated
Contain some cell organelles
Cell membrane contains
receptors to respond to stimuli
Transmit graded potentials
towards the soma
Axons (nerve fiber)
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Originate at a cone-shaped region – the
axon hillock
A single process that transmits action
potentials away from the soma
May be long (1 meter) or short (1 mm)
May branch (=collaterals)
Collaterals end at
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axonal terminals
synapse with neurons or effector cells (muscles
or glands)
The Myelin Sheath
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Lipid-rich, covering of axons
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Oligodendrocytes in CNS
Neurilemmocytes in PNS
Dendrites are never myelinated
Protects & electrically insulates
Increases speed of nerve impulses
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10-150x faster than unmyelinated fibers
Neurons
STRUCTURAL
CLASSIFICATIONS
Multipolar Neuron (slide #24)
Many processes originate from soma
Bipolar Neuron
Two processes originate from soma
Unipolar Neuron
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A single process originates from soma
Neurons
SPECIFIC TYPES
Pyramidal Cells (slide #29)
Pyramidal Cells
Pyramidal Cells
Purkinje Cells (slide #30)
Purkinje Cells of Cerebellum
Purkinje Cells
Purkinje Cells
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cytoskeleton stain
Peripheral Nerve
• Connective tissue
elements:
• Epineurium
(wraps nerve)
• Perineurium
(wraps fascicle)
• Endoneurium
(wraps axon &
myelin sheath)
Nerve, cross-section (slide #28)
Epineurium
Perineurium
Endoneurium
Nerve, cross section, Fascicles
Epineurium
Perineurium
Endoneurium
Nerve, cross section, Myelinated Fibers
Myelinated Axons, cross-section
Myelinated Axons, cross-section
Nerve, Long Section, 40X (slide # 28)
Nerve, long section, 100X
Neurofibrilar Node Nerve, 400X
Neurofibrilar Node, 1000X
Sheep Brain Dissection
Dura mater
partially removed
Sheep Brain Dissection
and
pia mater
Sheep Brain Dissection
Sheep Brain Dissection
Note: pituitary removed
Sheep Brain Dissection
Sheep
Brain in
Cross
Section
Key to Sheep Brain in Cross Section
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Gray Matter
White Matter
Corpus Callosum
Lateral Ventricle
Caudate Nucleus
Septum Pellucidum
Fornix
Optic Chiasm
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9. Third Ventricle
10. Thalamus
11. Corona Radiata
12. Hippocampus
13. Cerebral Aqueduct
14. Pituitary Gland
15. Pineal Gland
Human Cranial Nerves
Human Cranial Nerves
End of Lab 9 Presentation