histology 110 primary basic tissues of the body the
TRANSCRIPT
Tishk International University
Faculty of Pharmacy
Department of Pharmacy
HISTOLOGY – 110
Primary Basic Tissues of the Body
The Nervous Tissue Part -B
First Grade – Spring Semester 2019-2020
Instructor : Dr. Hiwa Bakir Banna
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Myelinated axon
Non myelinated axon
Peripheral nerve fiber showing
Node of Ranvier X 400Peripheral nerve fiber in sections X 100
Classification of neurons according to Function:1-Sensory neuron or afferent towards CNS. Carry messages in from the body's
tissues and sensory receptors to the CNS for processing.
2- Motor or efferent neurons carry instructions out from CNS to the body's tissues.
The simplest example is the knee jerk?
3-Interneurons(integration) In the CNS- process information between the sensory input and
motor output.
Classification of neurons according to shape:Neurons are classified according to a variety of criteria:
The most abundant and important type is Multipolar neurons present in both CNS and PNS
such as :
Pyramidal neurons in cerebral cortex gray matter
Purkinje neurons in cerebellar cortex
Stellate star shaped neurons in gray matter of spinal cord
And ganglionic neurons of the autonomic nervous system such as bipolar, multipolar and
pseudounipolar neurons.
2-Neuroglia :
Neuroglia cells provide metabolic and structural support for neurons, the number of
glia cells in the brain are ten time more than the number of neurons. Neurons would not be
able to function without support and protection from these glia cells. Glia cells also provide
insulation for nerve fibers(myelin sheath),nutrition, homeostasis and phagocytic activities.
They do not conduct impulses but have retained the ability to divide .
(Most brain tumors are caused by mutations in glia cells).
There are six types of neuroglia cells:
Neuroglial types in Central Nervous System are: 1-Astrocytes, (nutrition-binding neurons with blood vessels)
2-Microglia, protection( phagocytosis of bacteria …)
3-Oligodendrocyte ,(produce myelin )
4-Ependymal cells-lining ventricles of the brain and central canal of spinal cord
Neuroglial cells in Peripheral Nervous system: 1-Satellite cells (supporting ganglion cells)
2-Schwan cells (produce myelin in peripheral nerves).
multipolar neuron in
autonomic ganglia
Peripheral nervous System: Comprise of nervous tissues outside
brain and spinal cord ; small aggregates of nerve cells called peripheral ganglia and
nerves . A peripheral nerve is a bundle of nerve fibers, each has
a connective tissue coverings from deep to superficial is:
Endoneurium wraps each single nerve fiber(axon).
Perineurium: Wraps groups of fibers forming fascicles.
Epineurium: Wraps groups of fascicles to form larger
nerves or nerve trunk.
Peripheral Nerve Trunk
Peripheral Nerve
Discussion
with students
Red =Epineurium
Black arrow=Perineurium
Blue star = nerve fascicle Containing numerous myelinated
fibers-axons covered by EndoneuriumNode of Ranvier high power
low power
Node of Ranvier X 400
Pseudounipolar Neurons
in peripheral ganglia
multipolar neuron in
autonomic ganglia
stellate star shaped neurons from
Gray matter of spinal cord
Summary Features of The Nervous Tissues with student participation:
1-Excitable tissues and fast acting control system.
2-Composed of neurons with their processes(axon &dendrites) and supporting glia cells.
3-It triggers contraction of muscle and gland secretion
4-It shares muscle in one feature and that is (irritability) excitability
5-It has another unique feature which is conductivity.
6-It senses stimuli and transmits signals from one part of the body to another
(internal stimuli).
7-It allows the body to respond to the environment (external stimuli).
8-No connective tissue within C N S, only in PNS(..?) and superficial aspects
of brain and spinal cord( the three layers of Meninges).
9-Neurons have no Centrioles (cannot divide). ??
10-Bundles of myelinated axons are called tracts in the CNS and nerves in the PNS.
11- Neurons, for survival , need a continuous supply of oxygen and glucose.
End of Nervous Tissue
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References:
Wheater's Functional Histology by Barbara Young Elsevier 6TH ed. Churchill
Livingstone.edinburgh
Junqueira's Basic Histology: Text and Atlas, 13th ed / McGraw- Hill.
HISTOLOGY A TEXT AND ATLAS by Ross & Pawlina / Lippincott Williams and
Wilkins ,Fifth edition.
Textbook of Histology by Leslie Gartner pub: Elsevier 4th EDITION
Histology Books, Ebooks & Journals | US Elsevier Health
www.us.elsevierhealth.com/medicine/histology
Normal histology, with special reference to the ... - Internet Archive
https://archive.org/details/normalhistologyw00pier. Internet Archive.
Di Fiores Atlas of Histology with functional correlations. 12th ed. Wolters Kluwer/
Lippincott,& Wilkins Int.
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