2. THE N.S The nervous and endocrine systems control the functions of the body. The nervous and endocrine systems control the functions of the body.

3. FUNCTIONS (1) It receives information (stimuli) that arise either outside or inside the body from different sensory receptors. (1) It receives information (stimuli) that arise either outside or inside the body from different sensory receptors. These are grouped together to form sensory input. These are grouped together to form sensory input.

4. FUNCTION (2) It integrates and correlates these sensory input. (2) It integrates and correlates these sensory input. (3) It effects a response to an effector (muscle or gland) through the motor output. (3) It effects a response to an effector (muscle or gland) through the motor output.

5. CLASSIFICATION OF N.S. (1) Central nervous system (CNS) (1) Central nervous system (CNS) (2) Peripheral nervous system (PNS) (2) Peripheral nervous system (PNS)

6. CENTRAL NERVOUS SYSTEM It is formed of : It is formed of : The brain and spinal cord. The brain and spinal cord. They occupy the dorsal body cavity. They occupy the dorsal body cavity. They are the main centers where correlation and integration of nervous information occur. They are the main centers where correlation and integration of nervous information occur.

7. PERIPHERAL N.S It is the link between the CNS and peripheral structures. It is the link between the CNS and peripheral structures. It is formed of : It is formed of : 1.Cranial and Spinal nerves. 1.Cranial and Spinal nerves. 2.Their ramifications within the body. 2.Their ramifications within the body. 3.Associated Ganglia. 3.Associated Ganglia.

8. CLASSIFICATION OF NERVES Nerves are classified according to the direction in which they carry impulses : Nerves are classified according to the direction in which they carry impulses : (1) sensory (afferent): (1) sensory (afferent): They carry impulses toward the CNS. They carry impulses toward the CNS. (2) Motor (efferent) : (2) Motor (efferent) : They carry impulses from the CNS. They carry impulses from the CNS. (3) Mixed. (3) Mixed.

9. FUNCTIONAL CLASSIFICATION OF PNS 1. Sensory (Afferent): 1. Sensory (Afferent): A. Somatic : A. Somatic : It delivers impulses to the CNS from: It delivers impulses to the CNS from: Skin. Skin. Skeletal muscles. Skeletal muscles. joints. joints. B. Visceral : B. Visceral : It transmits impulses from the visceral organs. It transmits impulses from the visceral organs.

10. FUNCTIONAL CLASSIFICATION OF PNS 2. Motor (efferent ) 2. Motor (efferent ) A. Somatic : A. Somatic : It allows conscious (voluntary) control of skeletal muscles. It allows conscious (voluntary) control of skeletal muscles. B. Autonomic B. Autonomic It controls involuntary activity of smooth, cardiac muscles and glands. It controls involuntary activity of smooth, cardiac muscles and glands.

11. AUTONOMIC N.S It is divided into Sympathetic and Parasympathetic. It is divided into Sympathetic and Parasympathetic. In both there are afferent, efferent nerve fibers and ganglia. In both there are afferent, efferent nerve fibers and ganglia.

12. AUTONOMIC N. SYSTEM It has a chain of two motor neurons (Ganglia). It has a chain of two motor neurons (Ganglia). The first motor neuron is in the brain or spinal cord. The first motor neuron is in the brain or spinal cord. Its axon (Preganglionic) synapse with the second motor neuron (outside ) the CNS. Its axon (Preganglionic) synapse with the second motor neuron (outside ) the CNS. The axon of this neuron is (Postganglionic) extends to the organ which it serves. The axon of this neuron is (Postganglionic) extends to the organ which it serves.

13. INTERNAL STRUCTURE OF N.S. The interior of the N.S. is organized into gray and white matter. The interior of the N.S. is organized into gray and white matter.

14. GREY MATTER It is composed of large numbers of excitable nerve cells (Neurons) and their processes which are supported by specialized tissue (Neuroglia). It is composed of large numbers of excitable nerve cells (Neurons) and their processes which are supported by specialized tissue (Neuroglia).

15. NEURONE It is the structural and functional unit of the nervous system. It is the structural and functional unit of the nervous system. It receives and integrates information from sensory receptors or other neurons and transmit information to the effector organs. It receives and integrates information from sensory receptors or other neurons and transmit information to the effector organs.

16. PROCESSES OF NEURONS Dendrites : Dendrites : They are receptive processes. They are receptive processes. They can detect changes in the external or internal environment. They can detect changes in the external or internal environment.

17. PROCESSES OF NEURONS Axons : Axons : Carry information away from the cell body. Carry information away from the cell body. They can be divided into several collaterals. They can be divided into several collaterals. Terminal Buttons : Terminal Buttons : Are at the end of the axon where information is transferred to the dendrites of other neurons. Transmission of information between neurons is always by chemical not electrical means. Are at the end of the axon where information is transferred to the dendrites of other neurons. Transmission of information between neurons is always by chemical not electrical means.

18. FUNCTIONAL CLASSIFICATION OF NEURONS 1. Sensory 1. Sensory Carry information from the periphery to the CNS to reach the conscious level. Carry information from the periphery to the CNS to reach the conscious level. Their cell bodies are always outside the CNS in a ganglion. Their cell bodies are always outside the CNS in a ganglion.

19. 2. MOTOR (EFFERENT) Their cell bodies are always located in the CNS. They are divided into upper and lower motor neurons. They are divided into upper and lower motor neurons.

20. 3. ASSOCIATION (INTERNEURONS) They are relay neurons They are relay neurons connecting sensory and motor neurons. connecting sensory and motor neurons. They reside entirely within the CNS. They reside entirely within the CNS. Their cell bodies are always located in the CNS. Their cell bodies are always located in the CNS.

21. WHITE MATTER It consists of nerve fibers embedded in neuroglia. It consists of nerve fibers embedded in neuroglia. Tracts : Tracts : Nerve processes sharing common connections, course and functions. Nerve processes sharing common connections, course and functions.

22. REFLEXES They are rapid, predictable and involuntary responses to stimuli. They are rapid, predictable and involuntary responses to stimuli. They are : They are : (1) Somatic reflexes : (1) Somatic reflexes : Stimulate skeletal muscles. Stimulate skeletal muscles. (2) Autonomic reflexes : (2) Autonomic reflexes : Regulate smooth muscles. Regulate smooth muscles.

23. PROTECTION OF CNS The brain and spinal cord are covered with meninges and are suspended in the cerebrospinal fluid. The brain and spinal cord are covered with meninges and are suspended in the cerebrospinal fluid. They are further protected by the bones of the skull and vertebral column. They are further protected by the bones of the skull and vertebral column.

24. BRAIN Is divided into : Is divided into : Fore brain. Fore brain. Mid brain. Mid brain. Hind brain. Hind brain.

25. HIND BRAIN It consists of : It consists of : Cerebellum Cerebellum Medulla. Medulla. Pons. Pons.

26. MEDULLA OBLONGATA It is continuous caudally with the spinal cord. It is continuous caudally with the spinal cord. It extends rostrally to the pons. It extends rostrally to the pons.

27. PONS It owes its name to its appearance as that of a bridge connecting the two cerebellar hemispheres. It owes its name to its appearance as that of a bridge connecting the two cerebellar hemispheres.

28. CEREBELLUM It is an important center which is essential for accurate, coordinated and purposeful movements. It is an important center which is essential for accurate, coordinated and purposeful movements. It operates at an unconscious level. It operates at an unconscious level.

29. STRUCTURE It has an outer layer of grey matter (cerebellar cortex) which is highly convoluted and forms regular folds (Folia). It has an outer layer of grey matter (cerebellar cortex) which is highly convoluted and forms regular folds (Folia). The white matter forms the central core. The white matter forms the central core.

30. MID BRAIN It is rostral to the pons. It is rostral to the pons. Its dorsal surface is formed by four rounded eminences (Superior and Inferior Colliculi). Its dorsal surface is formed by four rounded eminences (Superior and Inferior Colliculi).

31. BRAIN STEM It forms a small part of the entire brain. It forms a small part of the entire brain. It consists of : It consists of : Medulla. Medulla. Pons. Pons. Mid brain (It is the smallest part of the brain stem). Mid brain (It is the smallest part of the brain stem).

32. BRAIN STEM It is attached to the cerebellum by three parts of nerve fibers (peduncles) : It is attached to the cerebellum by three parts of nerve fibers (peduncles) : Inferior to the medulla. Inferior to the medulla. Middle ( largest peduncle) to the pons. Middle ( largest peduncle) to the pons. Superior to the mid brain. Superior to the mid brain.

33. FORE BRAIN It consists of : Diencephalon. Two cerebral hemispheres.

34. DIENCEPHALON It is formed of four subdivisions in a dorsoventral direction It is formed of four subdivisions in a dorsoventral direction (1) Epithalamus (1) Epithalamus The Pineal Gland is its most notable part. The Pineal Gland is its most notable part. It is immediately rostral to the superior colliculi of the mid brain. It is immediately rostral to the superior colliculi of the mid brain.

35. DIENCEPHALON (2) Thalamus (2) Thalamus It is the largest part. It is the largest part. It has an important role in the sensory, motor and cognitive functions. It has an important role in the sensory, motor and cognitive functions.

36. DIENCEPHALON (3) Subthalamus (3) Subthalamus. (4) Hypothalamus. (4) Hypothalamus It is involved with the autonomic, limbic and cardiovascular systems. It is involved with the autonomic, limbic and cardiovascular systems.

37. CEREBRAL HEMISPHERES They represent the massive part of the forebrain. They represent the massive part of the forebrain. The two hemispheres are separated by the Great Longtudinal Fissure. The two hemispheres are separated by the Great Longtudinal Fissure. The fissure is occupied by the Falx Cerebri. The fissure is occupied by the Falx Cerebri.

38. CEREBRAL HEMISPHERES The cerebral cortex is highly convoluted for maximising the cortical surface area. The cerebral cortex is highly convoluted for maximising the cortical surface area. The convolutions are the Gyri and the furrows between them are the Sulci. The convolutions are the Gyri and the furrows between them are the Sulci. Some of these gyri and sulci mark the location of important functional areas. Some of these gyri and sulci mark the location of important functional areas.

39. CEREBRAL LOBES Each hemisphere is divided into four lobes which are named according to the names of the bones of the skull beneath which they lie. Each hemisphere is divided into four lobes which are named according to the names of the bones of the skull beneath which they lie.

40. CEREBRAL LOBES The lobes are : The lobes are : Frontal lobe. Frontal lobe. Its most anterior convexity is the frontal pole. Its most anterior convexity is the frontal pole. Parietal lobe. Parietal lobe. Temporal lobe. Temporal lobe. Its tip is the temporal pole. Its tip is the temporal pole. Occipital lobe. Occipital lobe. It terminates in the occipital pole. It terminates in the occipital pole.

41. STRUCTURE It consists of an outer layer of grey matter (cortex) and an inner mass of white matter. It consists of an outer layer of grey matter (cortex) and an inner mass of white matter.

42. BASAL GANGLIA They are large masses of cell bodies (grey matter) which are buried within the white matter. They are large masses of cell bodies (grey matter) which are buried within the white matter.

43. BASAL GANGLIA They are concerned with the control of muscle tone posture.They are important in the facilitation of appropriate motor behavior and the inhibition of unwanted movements. They are concerned with the control of muscle tone posture.They are important in the facilitation of appropriate motor behavior and the inhibition of unwanted movements.

44. BASAL GANGLIA The largest component is the Corpus Striatum. The largest component is the Corpus Striatum. It consists of : It consists of : Caudate nucleus. Caudate nucleus. Putamen and Globus pallidus. Putamen and Globus pallidus.

45. FUNCTIONAL CORTICAL AREAS (Frontal lobe) Precentral gyrus which contains the primary motor cortex. Precentral gyrus which contains the primary motor cortex. It is the highest level in the brain for the control of voluntary, skilled movements(muscles of speech, fascial expression and hand movements). It is the highest level in the brain for the control of voluntary, skilled movements(muscles of speech, fascial expression and hand movements). The opposite half of the body is represented in a highly precise fashion. The opposite half of the body is represented in a highly precise fashion.

46. UPPER MOTOR NEURONES They are in the motor cerebral cortex. They are in the motor cerebral cortex. Their axons form the descending tracts (corticospinal and corticobulbar) which control the activity of the lower motor neurons. Their axons form the descending tracts (corticospinal and corticobulbar) which control the activity of the lower motor neurons.

47. LOWER MOTOR NEUROENS Their cell bodies are in the spinal cord and brain stem. Their cell bodies are in the spinal cord and brain stem. They constitute the final pathway by which the nervous system controls the skeletal muscles. They constitute the final pathway by which the nervous system controls the skeletal muscles.

48. FUNCTIONAL CORTICAL AREAS (PARIETAL LOBE) Postcentral gyrus (primary somatosensory cortex) Postcentral gyrus (primary somatosensory cortex) It is the site of termination of pathways carrying touch, pressure, pain and temperature from the opposite half of the body. It is the site of termination of pathways carrying touch, pressure, pain and temperature from the opposite half of the body.

49. FUNCTIONAL CORTICAL AREAS Occipital Lobe : Occipital Lobe : Visual cortex Visual cortex Temporal Lobe : Temporal Lobe : Auditory cortex Auditory cortex

50. CORTICAL FIBERS Corona Radiata Corona Radiata It is a radiating pattern which It is a radiating pattern which is formed from the afferent and efferent fibers between the cerebral cortex and subcortical structures. is formed from the afferent and efferent fibers between the cerebral cortex and subcortical structures.

51. CORTICAL FIBERS Internal Capsule Internal Capsule It is deep inside the hemisphere. The fibers are arranged as a dense sheet of white matter It is deep inside the hemisphere. The fibers are arranged as a dense sheet of white matter

52. CORTICAL FIBERS Corpus Callosum Corpus Callosum It is a sheet of transversely running nerve fibers (Commissural Fibers) which link corresponding areas of the two cerebral cortices. It is a sheet of transversely running nerve fibers (Commissural Fibers) which link corresponding areas of the two cerebral cortices. It lies in the depths of the longtudinal fissure. It lies in the depths of the longtudinal fissure.

53. VENTRICULAR SYSTEM It is the site of production of the CSF which is secreted by the choroid plexus. It is the site of production of the CSF which is secreted by the choroid plexus.

54. VENTRICULAR SYSTEM Fourth ventriclrre Fourth ventriclrre It is the rostral continuation of the central canal of the spinal cord. It is the rostral continuation of the central canal of the spinal cord. It is a shallow, rhomboid-shaped depression on the dorsal surface of the medulla and pons beneath the cerebellum. It is a shallow, rhomboid-shaped depression on the dorsal surface of the medulla and pons beneath the cerebellum.

55. VENTRICULAR SYSTEM Cerebral aqueduct Cerebral aqueduct It runs through the mid brain beneath the superior and inferior colliculi. It runs through the mid brain beneath the superior and inferior colliculi. Third ventricle Third ventricle It is a slit like chamber which is narrow from side to side. It is a slit like chamber which is narrow from side to side. Its lateral walls are formed by the diencephalon especially the thalamus. Its lateral walls are formed by the diencephalon especially the thalamus.

56. VENTRICULAR SYSTEM Lateral ventricle Lateral ventricle It is an extensive chamber within the cerebral hemisphere. It is C – shaped. It is an extensive chamber within the cerebral hemisphere. It is C – shaped. It communicates It communicates with the third ventricle through the interventricular foramen (foramen of Monro). with the third ventricle through the interventricular foramen (foramen of Monro).