nervous tissue. 【 objectives 】 1. to identify and describe: a.the microscopic structure of the...
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Nervous Tissue
【 Objectives】
1. To identify and describe:
A. The microscopic structure of the neuron— including cell body, axon and dendrites
B. Differentiate a myelinated nerve fibers from an unmyelinated nerve fibers
2. To understand and describe
A. The structure of a synapse
B. The structure of sensory nerve termination (free nerve termination, tactile corpuscle, lamellar corpuscle and muscle spindle) or motor nerve termination (neuromusclar junction).
C. General histological features of central nervous system, i.e. spinal cord, cerebellum, and cerebrum.
What is the principal elements of the NS?
nervous tissue (NT)
What does the nervous tissue consist of ?
nerve cells (neurons)
neuroglial cells (glial cell)
What is feature of the nerve cells ?
(soma, perikaryon) cell body
processes dendrites
axon
plasma membrane
cytoplasm:
nucleus:
Nissl body neurofibrilsand neurofibrils
??
large, spherical, pale-staining;a prominent nucleolus
distinguish?
Axon hillock
Where do cell bodies of the neurons distribute?
Where do processes of the neurons
distribute?
gray matter, cortex, nuclei
white matterand the whole body
Gray matterWhite matter
Observation: No1
central canal white matter white matter
Gray matter
butterfly-like shape or H-like shape
neuronal cell bodies,dendrites and the initial unmyelinated portions of axons and glial cells
anterior horn
posterior horn
intermediate zone
myelinated axons, oligodendrocytes
Focus on neuron
Neuron
Glial cells
How many types of the nerve fibers?
What are nerve fibers?
Nerve fibers formed by the axon which be wraped by Schwann cellsor oligodendrocytes
CNS PNS
myelinated NF
unmyelinated NF
axon
myelin sheath
node of Ranvier
What is the myelin sheath? How does the myelin sheath be formed?
How does the impulse be propagated in the myelinated and unmyelinated fibers?
How to distinguish the myelinated and unmyelinated fibers in the slides
What is the function of the myelin sheath?
internode
Observation: No31
sciatic nerve transverse section longitudinal section
perineurium epineurium
nerve nerve fibers are grouped in bundle
Relationship between the nerve fibers and nerve
endoneurium
axon
myelin sheath
node of Ranvier
transverse section longitudinal section
neurilemma
Unmyelinated nerve H & EObservation: No.41
transverse section of the nerve
Demonstration slide
neurons( Nissl staining )
Neurofibril ( silver staining )
Myelinated fibers( osmic acid staining )
sensory nerve ending
A. free never ending
B. encapsulated nerve ending
a. tactile corpuscle; b. lamellar corpuscle c. muscle spindle
Meissner’s corpuscle
(tactile corpuscles) Be involved the reception of light touch)
Pacinian corpuscles
(lamellated corpuscles)Be involved the reception of coarse touch,deep or heavy pressure,vibration and tension
muscle spindle
Detect changes in the length (distension) of extrafusal muscle fibers and relay this information to the spinal cord
Motor nerve terminations
somatic motor nerve terminations
visceral motor nerve terminations
Synapse ( silver staining) in the LM
Definition of the synapse; the structure of the synapse
Cerebrum
A: molecular layerB: external granular layerC: external pyramidal layerD: internal granular layerE: internal pyramidal layerF: multiform layer
Cerebral cortex (gray matter)
White matter
Cerebellum
A: molecular layer, B: Purkinje cell layer
C: granular layer
gray matter
White matter
Myenteric nerve plexus
Oligodendrocytes
NT
nerve cells
(neurons)
neuroglial cells (glial cell)
(Supporting cells)
•Soma
cell body
dendrites:
axon:
processes
plasma membrane:
cytoplasm
nucleus:
excitable
Nissl body
neurofibrils
LM: basophilic granular
EM: rER, ribsom
LM: brownish black filamentsEM: neuofilaments and microtubule
large, spherical, pale-staining; a prominent nucleolus.
one or more /neuron; usually short and thick, and branched; dentritic spines on surfaces;
one axon each neuron; long and thin, does not branch profusely; derived from axon hillock; devoid of Nissl bodies;axon terminals (buttons) contain
vesicles with neurotransmitters in them
CNS:
PNS:
astrocytes, oligodendrocytes,
microglia, ependymal cells
Schwann cells, capsular cells (satellite cells)
NT
nerve cells
(neurons)
neuroglial cells (glial cell)
(Supporting cells)
•Soma
cell body
dendrites:
axons:
processes
plasma membrane:
cytoplasm
nucleus:
excitable
Nissl body
neurofibrils
LM: basophilic granular
EM: rER, ribsom
LM: brownish black filamentsEM: Neuofilaments and microtubule
large, spherical, pale-staining; a prominent nucleolus.
One or more /neuron; Usually short and thick, and branched; Dentritic spines on surfaces;
CNS:
PNS:
astrocytes, oligodendrocytes,
microglia, ependymal cells
Schwann cells, capsular cells (satellite cells)
oligodendrocytes,
Schwann cells
surrounding nerve fibermyelinated NF
unmyelinated NF
nerve endings
sensory (receptors)
motor (effectors)
free nerve endingstactile corpuscles Lamellated corpuscles muscular spindles
somatic (motor end plate)visceral
Homework
Draw the picture of the neuron.
THANK YOU