).nervous tissue (system-4 · 2015. 12. 20. · ).nervous tissue (system-4 is divided into 1- the...
TRANSCRIPT
![Page 1: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/1.jpg)
4-Nervous Tissue (system).
Is divided into
1- The central nervous system (CNS), consisting of the brain and the spinal cord
2-The peripheral nervous system (PNS) , composed of nerve fibers and nerve cells which called nerve ganglia or neurons .
![Page 2: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/2.jpg)
![Page 3: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/3.jpg)
Neurons .
Are anatomic and functional units consist of three parts :-
![Page 4: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/4.jpg)
1- Dendrites , multiple elongated processes specialized in receiving stimuli from the environment .
2- Cell body, perikaryon the trophic center.
3- The axon , single process specialized in generating or conducting nerve impulses to other cells .
![Page 5: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/5.jpg)
![Page 6: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/6.jpg)
![Page 7: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/7.jpg)
Neurons are classified on the basis of the number of processes extending from the cell body to :-
1-Multipolar, neurons have an axon and two or more dendrites
2-bipolar , neurons have one axon and one dendrites
3-Unipolar, (actually pseudounipolar) have one process the axon , that divides close to cell body to two long processes.
![Page 8: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/8.jpg)
![Page 9: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/9.jpg)
Synapses Are specialized junctions between neurons that
facilitate transmission of impulses from one neuron to another.
Synapses between neurons may be classified morphologically as :
1-Axodendritic, occuring between axons and dendrites.
2-Axosomatic, occuring between axons and cell body
3-Axoaxonic , occuring between axons and axons.
4-Dendrodendritic, occuring between dendrites and dendrites.
![Page 10: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/10.jpg)
![Page 11: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/11.jpg)
Myelinated and Unmyelinated NervesNerves are composed of bundles of nerve fibers held
together by perineurium and connective tissue . Each nerve fiber consist of an
axon that is surrounded by a cellular investment called the neurilemma or the sheath of Schwann .
In addition , the fiber may be myelinated or unmyelinated which do not have myelin , if present, ediately around the axon then called myelinated nerves.The myelin sheath is segmented and this site is called the node of Ranvier .
![Page 12: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/12.jpg)
Myelinated and Unmyelinated Nerves
• A myelin sheath is a protective layer that develops over nerves in the central nervous and peripheral nervous systems. Myelin sheaths are composed of fatty tissues and proteins.
• In the central nervous system, these sheaths are produced by oligodendrocytes, which can lay a myelin sheath over a number of axons.
• In the peripheral nervous system, myelin sheaths are produced by Schwann cells, which place a myelin sheath over a single axon.
![Page 13: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/13.jpg)
![Page 14: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/14.jpg)
![Page 15: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/15.jpg)
Spinal cordIn cross section, the spinal cord is organized into
two discrete parts exhibits a butterfly - shaped grayish-tan inner substance, the gray matter surrounding the central canal ,
and a whitish peripheral substance , the white matter which contains only myelinated and unmyelinated axons traveling to and from other parts of the spinal cord and to and from the brain .
The gray matter contains neuronal cell bodies and their dendrites, along with axons and neuralgia
![Page 16: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/16.jpg)
![Page 17: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/17.jpg)
Nerve ending
1-Pacinian corpuscles,are large ovoid structures found in the deeper dermis and hypodermis also it found in the pancreas .
2-Meissner ,s corpuscles , are touch receptors that found in the papillary layer of hairless skin
3-Ruffini endings , are the simplest mechanoreceptors ,they have an elongated fusiform shape .
4-Motor end plates , are the physiologic contact between nerve and muscle.
![Page 18: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/18.jpg)
![Page 19: ).Nervous Tissue (system-4 · 2015. 12. 20. · ).Nervous Tissue (system-4 Is divided into 1- The central nervous system (CNS), consisting of the brain and the spinal cord 2-The peripheral](https://reader036.vdocument.in/reader036/viewer/2022071610/6149cce312c9616cbc68ff5a/html5/thumbnails/19.jpg)