1. The central nervous system Prepared by Nouf Alyami

2. Contents CNS PNS the nerves tissue the brain parts The brain meninges The brain barriers cerebrum The Basal ganglia Cerebral cortex The spinal cord diseases

4. peripheral nervous system consists of 12 pairs of cranial nerves, which emerge from your brain and mainly serve your head and neck. It also contains 31 pairs of spinal nerves, which branch off from your spinal cord and supply the rest of your body. Subdivision of the nervous system CNS PNS Brain Spinal cord Outside these organs

7. CNS White matterGray matter

8. The brain Cerebral cortex White matter

9. Cerebral cortex The following six layers are present: 1. the molecular layer: it is the most superficial layer. It is formed mainly of the nerve fibres (axons & dendrites) of the nuclear and the pyramidal cell layers. 2.The External nuclear: it is formed of stellate- shape cells. 3.The small pyramidal cell layer:it is formed of small pyramidal-shape nerve cells. 4.The internal nuclear: it is formed of small stellate-shape nerve cells. 5.The large Pyramidal cell layer:it is formed of large pyramidal-shape nerve cells. 6.The Polymorphic cell layer: it is formed of different nerve cells and fibers.

10. pyramidal

11. The spinal cored White matter Gray matter

13. Nerves tissue Supporting cells of nervous tissues: 1-Astrocytes. 2-Microglia. 3-Ependymal. 4-Oligodendrocytes. 5-Schwann cells. Neurons. classification of neurons on the basis of structure: 1-Multipolar. 2-Bipolar. 3-unipolar.

14. 1-Astrocytes:

16. 3-Ependymal:

17. 4-Oligodendrocytes:

18. 5-Schwann cells:

19. The neroglia These are the supporting cells and fibres which are present between the neurones of the brain and spinal cored. Type and function: 1. protoplasmic macroglia nutritive 2. Fibrous macroglia White mater Support isolate 3. Microglia Grey & white Phagocytic cells 4. oligodendroglia Grey & white Myelin sheaths Grey mater

21. classification of neurons on the basis of structure:

22. Video time

24. The Brian

25. The brain meninges The central nervous system is covered by 3 protective membranes called meninges These meninges are: 1.Pia mater 2.Arachnoid mater 3.Dura mater

27. The pia mater: It is the vascular membrane of the meninges. It fits directly on the outer surface of the brain and spinal cord. The pia mater is formed of : autre layer which is formed of collagenous bundles. inner layer which is formed of reticular and elastic fibres. The pia is covered with simple squamous epithelium

28. The arachnoid mater: it is formed of C.T fibres devoid of blood vessels. The subarechnoid space is area between arachniod mater and the pia mater. It contains: the cerebro –spinal fluid (C.S.F). the blood vessels of the brain. N.B. the subarachnoid space is narrow but in certain areas, it may become wide to form the subarachnoid cisternae.

29. The (C.S.F): It is about 135 c.c circulating in the brain ventricles, in the central canals of the brain and the spinal cord as well as in the subarachnoid space.it is formed by the choroid plexus of the brain ventricles. Any obstruction to the normal passage of the C.S.F causes the fluid to accumulate in the brain ventricles leading to increase in the intracranial pressure (Hydrocephalus) The choroid plexuses: They are formed by single layer of cuboidal cells with a plexus of blood capillaries. They are present in the wall of the brain ventricles.

30. Video time

31. The dura mater: It is the moust external covering of the brain. It is formed of dense C,T rich in collagenous fibres. it contains venous sinuses which drain the blood and the C.S.F from the brain.

32. The brain barriers The brain cells and the cerebro spinal fluid in the brain cavities and canals are protected from micro organisms and other harmful substances which may be present in the circulating blood by 3 barriers. And they are: 1. the blood brain barrier. 2. the blood C.S.F barrier. 3. the brain C.S.F barrier.

33. 1. the blood brain barrier. 2. the blood C.S.F barrier. 3. the brain C.S.F barrier.

34. The brain consists of the following parts The brain stemThe cerebrum The cerebellum

35. The brain stem connects the brain with the spinal cord and is composed of 3 structures: the midbrain, pons, and medulla oblongata. The brain stem provides us with automatic functions that are necessary for survival. The cerebellum is located near the base of the head. It creates automatic programs so we can make complex movements without thinking.

36. cerebrum The is two hemispheres connected by corpus callosum, each hemispheres contains of grey and white matter which contain the basal ganglia.

37. Cerebral map

38. Homunculus

39. The Basal ganglia The Basal ganglia are formed of 4 nuclei which are present in the white matter. The Nuclei of the Basal ganglia: 1. the Caudate nucleus 2. the Lentiform nucleus 3. the Claustreum nucleus 4. the Amygdaliod nucleus

40. The Basal ganglia

41. The spinal cored

42. 8 12 5 5 1

43. Each part of the C.N.S is composed of: Grey and white matter. Nucleus in C.N.S.: group of nerve cells laying very close to each other and having the same function. Tract: group of nerve fibres (axons) which arise from the same origin and terminate at the same termination and they have the same function. Bundle: group of nerve fibres some them are ascending and the other descending. the fibres arise from the different origin and terminate at the same termination.the fibres of the bound carry different inpules. Relay (synapse) commissure(is a band of with matter connecting a part of the C.N.S on one side with the same part on the other side.

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46. diseases Epilepsy :  has deen recognized for 2400 years,drived from the Greek means attack.  It is syndrome of disturbed electrical activity in the brain. Alzheimer's:  dementia (among older people)  Which involves the parts of the brain that control thought, memory, and language. Parkinson :  The most common diseases.  Occurs between 50 and 65 age.  It may be inherited, man are likely to have it than women.