neevous system

Centra nervous system consist of

Brain and spinal cord

Brain site parts

Site: Inside skull.

Parts:

*Cerebrum (2 cerebral

hemispheres): 4 lobes; (frontal,

parietal, occipital & temporal).

Site: Inside vertebral column, 45 cm long & its end is tapering

(conus medullaris).

Segments: 31 (8 cervical, 12 thoracic, 5 lumbar, 5 sacral & 1

*Cerebellum.

coccygeal).

End: Tapering (conus medullaris).

2 enlargements: Cervical & lumbar, where N. plexuses arise.

*Brainstem;

Midbrain, pons & medulla oblongata.

*Diencephalon;

Thalamus, hypothalamus, subthalamus,

metathalamus & epi thalamus

Structure

Spinal cord site

Site: Inside vertebral column, 45 cm long & its end is tapering

(conus medullaris

Segments end and 2 enlargements

Segments: 31 (8 cervical, 12 thoracic, 5 lumbar, 5 sacral & 1

*Cerebellum.

coccygeal).

End: Tapering (conus medullaris).

2 enlargements: Cervical & lumbar, where N. plexuses arise

Structure

Outer white matter; nerve fibers forming tracts.

*Inner gray matter; nerve cells. H-shaped;

-2ventral horns (motor nuclei).

-2 dorsal horns (sensory nuclei).

-2 lat. horns (contain sympathetic nuclei in thoracic & upper 2

lumbar segments while contain para-sympathetic nuclei in 2nd,

3rd & 4th sacral segments).

meninges

Meninges: -Coverings of C.N.S, arranged as pia, arachnoid & dura mater

(from inside to outside)

Peripheral nervous system spinal

Spinal From spinal cord.

• 31 pairs:

8 cervical, 12 thoracic, 5 lumbar, 5 sacral & 1 coccygeal.

-Arises by 2 roots;

• Ant. (ventral): Contains motor fibers

• Post. (dorsal): Contains sensory fibers.

-Both roots unite forming mixed trunk which divides into mixed ant. & post. rami.

Cranial nerves

• From brain & leave skull through foramina.

• 12 pairs:

I-Olfactory

Il-Optic

Ill-Oculomotor

IV-Trochlear

V-Trigeminal

VI-Abducent

VIl-Facial

VIll-Auditory

IX-Glossopharyngeal

X-Vagus

XI-Accessory

XII-Hypoglossal.

Autonomic 2 types

Autonomic nervous system (concerned with involuntary activities)

A] Sympathetic :Pair of sympathetic hains along side of vertebral column

B] Parasympathetic: Cranial outflow rom cranial nerves; III, VII, IX, X & sacral utflow; from spinal segments S2- S4.