The Nervous System

1. The Nervous System

3. Organization of the Nervous System • Structural Classification • Functional classification

4. Structural Classification • Central nervous system (CNS) consists of brain and spinal cord. • Peripheral nervous system (PNS) consists of spinal and cranial nerves.

5. Functional classification • The sensory, or afferent. • The motor, or efferent.

6. The somatic nervous system voluntary nervous system The autonomic nervous system involuntary nervous system Sympathetic and parasympathetic

7. Functional anatomy of the brain • Cerebral hemispheres. • Diencephalon. • Brain stem. • Cerebellum.

9. Cerebral Hemispheres • The most superior and largest part of the brain. • The entire surface of the cerebral hemispheres have elevated ridges of tissue called gyri,separated by shallow grooves called sulci • Fissures are the deeper grooves which separate large regions of the brain

11. The cerebral hemispheres are separated by a single deep fissure the longitudinal fissure • Other fissures divide each cerebral hemispheres into number of lobes • Somatic sensory area is located in the parietal lobe posterior to the central sulcus • The body represented upside-down manner • The visual area is located in the in the posterior part of the occipital lobe

13. The auditory is located in the temporal lobe • The olfactory area is found deep inside the temporal lobe • The primary motor area is anterior to the central sulcus in the frontal lobe. • Broca’s area is found at the base of the precentralgyrus • Speech area is located at the junction of the temporal, parietal, and occipital lobes.

15. The cell bodies of neurons are found only in the outermost gray matter of cerebrum ,the cerebral cortex • The deeper cerebral white matter is composed of fiber tracts carrying impulses to or from the cortex.

17. Diencephalon • The major structures of diencephalon are the thalamus, hypothalamus and epithlamus

19. The thalamus • It encloses the shallow third ventricle of the brain • It is a relay station for sensory impulses.

21. The hypothalamus • It makes the floor of the diencephalon • It is an important autonomic nervous system centre (body temperature, water balance, and metabolism) • The hypothalamus regulates the pituitary gland

23. epithalamus • It forms the roof of the third ventricle • The choroid plexus, form the cerebrospinal fluid.

25. Brain stem • Midbrain ,pons,and medulla oblongata

27. cerebellum • . • It has two hemispheres and a convoluted surface. • Precise timing for skeletal muscle activity. • .

28. Protection of the central nervous system • Bone (skull and vertebral column) • Membranes (meninges) • Watery cushion (CSF) • Blood brain barrier

30. meninges • Dura mater…double-layered membrane • periosteal layer • meningeal layer • Dural sinuses….collect venous blood • Falx cerebri • Tentorium cerebelli

32. Arachnoid mater • Pia mater..delicate pia mater • The subarachnoid space …C.S.F • Arachnoid villi

34. C.S.F • Watery similar in it’s makeup to blood plasma, from which it forms.

36. Is formed from blood by the choroid plexuses that found in the lateral and third ventricles then to the subarachnoid space through the three opening in the wall of the fourth ventricles

38. Spinal cord • It extends from the foramen magnum of the skull to the 1st and 2nd lumbar vertebra • The spinal is protected by meninges which is extend well beyond the end of spinal cord. • 31pairs of spinal nerves • Caudaequina • Cervical and lumbar enlargement

40. Gray mater of the spinal cord • Butterfly –H • Posterior or dorsal horn anterior or ventral horn and lateral horn • Gray mater surrounds the central canal • Dorsal root, dorsal root ganglion, ventral root

42. White mater of the spinal cord • Posterior column (ascending). lateral, and anterior columns (ascending and descending).