Histology of the Nervous System
Lab 8
Lab 8 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)
Histology of Nervous Tissue Parts of a Neuron
Neuron Structure – Cell Body (= Soma)
contains the usual cellular organelles synthesis & metabolism occurs primarily in the soma the outer cell membrane contains the receptors for
incoming information (stimuli) most cell bodies are located within the CNS
clusters of neuron cell bodies in the CNS are called nucleinuclei clusters of neuron cell bodies in the PNS are called gangliaganglia
Neuron Structure - Processes
dendrites short, tapering, highly branched
processes or extensions from soma
not myelinated the location for some cell
organelles sites of receptive or input regions transfer information to the cell
body transmit graded potentials - not
action potentials
Neuron Structure - Processes
axons a long thin cylindrical cytoplasmic
projection starts at a cone-shaped region – the axon
hillock may be long (1 meter) or short (1 mm) a long axon is called a nerve fiber transmit information away from the soma ends in many branches
known as axonal terminals may be 10,000 on one nerve form synapses (junctions) with neighboring
neurons or with effector cells (muscles or glands)
Neuron Structure - Axons (continued)
filled with axoplasm and surrounded by an axolemma
action potentials start at the axon hillock (trigger zone); travel along the axon to the axon terminal
axon terminal has the secretory component
Action Potential (nerve impulse) arrival causes the release of stored neurotransmitters
neurotransmitters transfer the message across a synapse to the next neuron or to an effector
neurotransmitters can excite or inhibit the action of the next cell in the pathway
Histology of Neurons – Myelin Sheath
the myelin sheath lipid-rich, segmented covering on an
axon primarily along the larger, longer axons dendrites are never myelinated myelin protects & electrically insulates
axon increases the speed of nerve impulses
myelinated fibers conduct impulses 10-150x faster than unmyelinated fibers
150 m/sec vs. 1 m/sec
Nervous Tissue (slide # 24)
Unipolar Neuron
Bipolar Neuron
Multipolar Neuron
Pyramidal Cells (slide #29)
Pyramidal Cells, 2
Pyramidal Cells 3
Purkinje Cells of Cerebellum, slide # 30)
Purkinje Cells, 2
Purkinje Cells, 3
Purkinje Cells, 4 cytoskeleton stain
Spinal Cord with Dorsal Root
Sensory Neurons of Dorsal Root
Dorsal Root, Sensory Neurons
Dorsal Root, Sensory Neurons
Dorsal Root, Sensory Neurons with Satellite Cells
Peripheral Nerve
Nerve, cross-section (slide #28)
Nerve, cross section, Fascicles
Nerve, cross section, Myelinated Fibers
Myelinated Axons, cross-section
Myelinated Axons, cross-section
Nerve, Long Section, 40X (slide # 28)
Nerve, long section
Neurofibrilar Node Nerve, 400X
Neurofibrilar Node
Sheep Brain Dissection
Sheep Brain Dissection
andandpia materpia mater
Sheep Brain Dissection
Sheep Brain Dissection
Sheep Brain Dissection
Sheep Brain in Cross Section
Key to Sheep Brain in Cross Section
1. Gray Matter 2. White Matter 3. Corpus Callosum 4. Lateral Ventricle 5. Caudate Nucleus 6. Septum
Pellucidum 7. Fornix 8. Optic Chiasm
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 8 Presentation
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