Nerve Tissue Al-Maarefa College

Nerve Tissue Cells have very high ability to – Respond to stimuli – Transmit impulses

Nerve Tissue

NEURON is the main nerve cell)

Nerve Tissue NEURON is the main nerve cell – Cell Body(3) – Dendrites (5) – Axon(1)

Motor Neurone

Cell body Dendrites Axon – Covered by Myelin sheath

Neuron Multipolar Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy

Neuron's – cerebral cortex Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy

Neuron's – spinal cord Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy

Nerve and Reflex Arc

Nerve Fiber (Axon) Nerve fibers are long nerve cell processes (axon cylinder, axon) with a surrounding membrane Schwann cells (neurolemmocytes, peripheral glial cells) enfold the axon and form an insulating cover known as Schwann’s sheath (neurolemma). Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy Stain: osmium tetroxide; magnification: × 1000

Nerve Fiber (Axon) Myelinated nerve fiber, i.e., the axon is covered by a myelin sheath, which is rich in lipids. Every 0.8 to 1.0 mm, a node of Ranvier subdivides the myelin sheath into segments or internodes. Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy Stain: osmium tetroxide; magnification: × 1000

Sciatic nerve – cross section 1 Fascicle (nerve fiber bundle) 2 Perineurium 3 Epineurium 4 Artery 5 Vein 6 Adipose tissue Stain: alum hematoxylin; magnification: × 10 Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy

Glial Cells Glial cells (Neuroglia) or (Glia) (Greek "glue” Non-neuronal cells that: 1- maintain homeostasis, 2- form myelin, 3- provide support and protection for the brain's neurons They occupy the entire space between neurons and separate nerve cells from blood vessels

Glial Cells - Functions 1.Surround neurons and hold them in place 2.Supply nutrients and oxygen to neurons 3.Insulate one neuron from another 4.Destroy pathogens and remove dead neurons

Glial Cells - Types Astrocytes (macroglia) Oligodendrocytes Microgliocytes

Astrocytes Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy Most abundant Deal with homeostasis – relate to vessels

are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including :glialcells brainspinal cord 1- biochemical support of endothelial cells that form the blood–brain barrier,endothelial cellsblood–brain barrier 2- provision of nutrients to the nervous tissue, 3-maintenance of extracellular ion balance, 4- and a role in the repair and scarring process of the brain and spinal cord following traumatic injuries

Astrocytes and nerve cells Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy

Microglia

Microglia : Microglia are the main resident immunological cells the CNS Oligodendrocytes: – Closely related to neurons – Provide myelin protection for CNS neurons

Neurons and glial cells Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy

Neuron and glial cells Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy

Summary Nerve Tissue Cells: – Neurons: Myelinated Non-myelinated

Summary Nerve Tissue Cells: – Neurons: Myelinated Non-myelintaed – Neuroglial cells: Astrocytes Microglia Oligodendrocytes