Nervous Tissue. 【 Objectives 】 1. To identify and describe: A.The microscopic structure of the...

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