The Nervous SystemThe Nervous System

Organization of the Nervous SystemOrganization of the Nervous System

Structural ClassificationStructural Classification Functional classificationFunctional classification

Structural ClassificationStructural Classification

Central nervous system (CNS) consists of Central nervous system (CNS) consists of brain and spinal cord.brain and spinal cord.

Peripheral nervous system (PNS) consists of Peripheral nervous system (PNS) consists of spinal and cranial nerves.spinal and cranial nerves.

Functional classificationFunctional classification

The sensory, or afferent.The sensory, or afferent.

The motor, or efferent.The motor, or efferent.

The somatic nervous systemThe somatic nervous system

voluntary nervous systemvoluntary nervous system

The autonomic nervous systemThe autonomic nervous system

involuntary nervous systeminvoluntary nervous system

Sympathetic and parasympathetic Sympathetic and parasympathetic

Functional anatomy of the brainFunctional anatomy of the brain

Cerebral hemispheres.Cerebral hemispheres. Diencephalon.Diencephalon. Brain stem.Brain stem. Cerebellum.Cerebellum.

Cerebral HemispheresCerebral Hemispheres

The most superior and largest part of the brain.The most superior and largest part of the brain. The entire surface of the cerebral hemispheres The entire surface of the cerebral hemispheres

have elevated ridges of tissue called have elevated ridges of tissue called gyri,separated by shallow grooves called sulcigyri,separated by shallow grooves called sulci

Fissures are the deeper grooves which separate Fissures are the deeper grooves which separate large regions of the brainlarge regions of the brain

The cerebral hemispheres are separated by a single The cerebral hemispheres are separated by a single deep fissure the longitudinal fissuredeep fissure the longitudinal fissure

Other fissures divide each cerebral Other fissures divide each cerebral hemispheres into hemispheres into number of number of lobeslobes

Somatic sensory area is located in the parietal lobe Somatic sensory area is located in the parietal lobe posterior to the central sulcusposterior to the central sulcus

The body represented upside-down mannerThe body represented upside-down manner The visual area is located in the in the posterior part The visual area is located in the in the posterior part

of the occipital lobeof the occipital lobe

The auditory is located in the temporal lobeThe auditory is located in the temporal lobe The olfactory area is found deep inside the The olfactory area is found deep inside the

temporal lobe temporal lobe The primary motor area is anterior to the The primary motor area is anterior to the

central sulcus in the frontal lobe.central sulcus in the frontal lobe. BrocaBroca’’s area is found at the base of the s area is found at the base of the

precentral gyrusprecentral gyrus Speech area is located at the junction of the Speech area is located at the junction of the

temporal, parietal, and occipital lobes.temporal, parietal, and occipital lobes.

The cell bodies of neurons are found only in The cell bodies of neurons are found only in the outermost gray matter of cerebrum ,the the outermost gray matter of cerebrum ,the cerebral cortex cerebral cortex

The deeper cerebral white matter is composed The deeper cerebral white matter is composed of fiber tracts carrying impulses to or from the of fiber tracts carrying impulses to or from the cortex.cortex.

DiencephalonDiencephalon

The major structures of diencephalon are the The major structures of diencephalon are the thalamus, hypothalamus and epithlamusthalamus, hypothalamus and epithlamus

The thalamusThe thalamus

It encloses the shallow third ventricle of the It encloses the shallow third ventricle of the brainbrain

It is a relay station for sensory impulses.It is a relay station for sensory impulses.

The hypothalamusThe hypothalamus

It makes the floor of the diencephalon It makes the floor of the diencephalon It is an important autonomic nervous system It is an important autonomic nervous system

centre (body temperature, water balance, and centre (body temperature, water balance, and metabolism)metabolism)

The hypothalamus regulates the pituitary glandThe hypothalamus regulates the pituitary gland

epithalamusepithalamus

It forms the roof of the third ventricleIt forms the roof of the third ventricle The choroid plexus, form the cerebrospinal The choroid plexus, form the cerebrospinal

fluid.fluid.

Brain stemBrain stem

Midbrain ,pons,and medulla Midbrain ,pons,and medulla oblongataoblongata

cerebellumcerebellum

..

It has two hemispheres and a convoluted It has two hemispheres and a convoluted surface.surface.

Precise timing for skeletal muscle activity.Precise timing for skeletal muscle activity.

..

Protection of the central nervous Protection of the central nervous systemsystem

Bone (skull and vertebral column)Bone (skull and vertebral column) Membranes (meninges)Membranes (meninges) Watery cushion (CSF)Watery cushion (CSF) Blood brain barrierBlood brain barrier

meningesmeninges

Dura materDura mater……double-layered membranedouble-layered membrane periosteal layerperiosteal layer meningeal layermeningeal layer Dural sinusesDural sinuses…….collect venous blood.collect venous blood Falx cerebriFalx cerebri Tentorium cerebelliTentorium cerebelli

Arachnoid materArachnoid mater Pia mater..delicate pia materPia mater..delicate pia mater The subarachnoid space The subarachnoid space ……C.S.FC.S.F Arachnoid villiArachnoid villi

C.S.FC.S.F

Watery similar in itWatery similar in it’’s makeup to blood plasma, s makeup to blood plasma, from which it forms.from which it forms.

Is formed from blood by the choroid plexuses Is formed from blood by the choroid plexuses that found in the lateral and third ventriclesthat found in the lateral and third ventricles

then to the subarachnoid space through the three then to the subarachnoid space through the three opening in the wall of the fourth ventricles opening in the wall of the fourth ventricles

Spinal cordSpinal cord

It extends from the foramen magnum of the It extends from the foramen magnum of the skull to the 1skull to the 1stst and 2 and 2ndnd lumbar vertebra lumbar vertebra

The spinal is protected by meninges which is The spinal is protected by meninges which is extend well beyond the end of spinal cord.extend well beyond the end of spinal cord.

31pairs of spinal nerves 31pairs of spinal nerves Cauda equinaCauda equina Cervical and lumbar enlargementCervical and lumbar enlargement

Gray mater of the spinal cordGray mater of the spinal cord

Butterfly Butterfly ––HH Posterior or dorsal hornPosterior or dorsal horn

anterior or ventral horn and lateral hornanterior or ventral horn and lateral horn Gray mater surrounds the central canalGray mater surrounds the central canal Dorsal root, dorsal root ganglion, ventral rootDorsal root, dorsal root ganglion, ventral root

White mater of the spinal cordWhite mater of the spinal cord

PosteriorPosterior column column (ascending). lateral, and (ascending). lateral, and anterior columns (anterior columns (ascending and descending).ascending and descending).