Transcript Nervous system

The Nervous System
Organization of the Nervous System


Structural Classification
Functional classification
Structural Classification


Central nervous system (CNS) consists of
brain and spinal cord.
Peripheral nervous system (PNS) consists of
spinal and cranial nerves.
Functional classification

The sensory, or afferent.

The motor, or efferent.
The somatic nervous system
voluntary nervous system
The autonomic nervous system
involuntary nervous system
Sympathetic and parasympathetic
Functional anatomy of the brain




Cerebral hemispheres.
Diencephalon.
Brain stem.
Cerebellum.
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





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





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
precentral gyrus
Speech area is located at the junction of the
temporal, parietal, and occipital lobes.


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.
Diencephalon

The major structures of diencephalon are the
thalamus, hypothalamus and epithlamus
The thalamus


It encloses the shallow third ventricle of the
brain
It is a relay station for sensory impulses.
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
epithalamus


It forms the roof of the third ventricle
The choroid plexus, form the cerebrospinal
fluid.
Brain stem

Midbrain ,pons,and medulla oblongata
cerebellum
.
It has two hemispheres and a convoluted
surface.
Precise timing for skeletal muscle activity.
.
Protection of the central nervous
system




Bone (skull and vertebral column)
Membranes (meninges)
Watery cushion (CSF)
Blood brain barrier
meninges






Dura mater…double-layered membrane
periosteal layer
meningeal layer
Dural sinuses….collect venous blood
Falx cerebri
Tentorium cerebelli




Arachnoid mater
Pia mater..delicate pia mater
The subarachnoid space …C.S.F
Arachnoid villi
C.S.F

Watery similar in it’s makeup to blood plasma,
from which it forms.
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

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
Cauda equina
Cervical and lumbar enlargement
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

White mater of the spinal cord

Posterior column (ascending). lateral, and
anterior columns (ascending and descending).