Brain pptx - دكتور نجاة نظري

Brain

THE MENINGES

Are membranes of the brain and include:
Dura mater
Arachnoid mater
Pia mater

1. Dura mater

It is the first layer and is fused to the endocranium within skull except:
• where it passes between the major parts of the brain to form rigid folds or partitions which incompletely subdivide the cranial cavity, and help to support the brain within it.
• Where the venous sinuses of the dura mater separate the dura mater from the endocranium.

Venous sinuses of dura mater:

These are venous channels which are lined with endothelium and lie external to the dura mater.

2. Arachnoiod mater

This is an exceedingly thin, almost transparent membrane, which is separated from the dura mater by a capillary interval called subdural space.

3. Pia mater

Is a close-fitting sheath which follows the contours of the brain and dips into all the irregularities of its surface (the immediate investment of the brain)

THE BLOOD VESSELS OF THE BRAIN

ARTERIES OF THE BRAIN
(circle of Willis)
The internal carotid and two vertebral arteries carry the total blood supply of the brain.

Vertebral arteries:

Each vertebral artery unite with its fellow at the lower border of the pons and form the median basilar artery.

Intracranial branches of the vertebral arteries:

• Posterior spinal artery
• Posterior inferior cerebellar artery
• Anterior spinal artery

Basilar artery
This artery is formed at the inferior border of the pons by the junction of the two vertebral arteries, and it terminates at the superior border of the pons by dividing into the two posterior cerebral arteries.

Branches of Basilar artery:

• Pontine branches
• The artery of the labyrinth (labyrinthine artery)
• The anterior inferior cerebellar artery
• The superior cerebellar artery
• The posterior cerebral arteries

Posterior cerebral artery branches:

• Small Central branches
• Posterior choroid artery

Internal carotid artery branches:

ICA gives off small branches, and divides into the middle and anterior cerebral arteries. The small branches are:
• Posterior communicating artery
• Anterior choroid artery
Each anterior cerebral artery connects to its fellow of the opposite side by the short anterior communicating artery.
Both anterior and middle cerebral arteries have central branches

PARTS OF BRAIN

• Forebrain
• Cerebrum
• Diencephalon
(thalamus and hypothalamus)
2. Midbrain N.B. midbrain and hindbrain called brain stem
3. Hindbrain
• pons
• medulla oblongata
• Cerebellum

• FOREBRAIN

• Cerebrum
• Diencephalon

CEREBRUM

Is by far the largest part.
It is composed of the two cerebral hemispheres which are partially separated by the falx cerebri lying in the longitudinal fissure.

THE LONGITUDINAL FISSURE

is the narrow cleft between the two hemispheres.

General features of hemisphere surface

• The frontal pole
• The occipital pole
• The temporal pole

Brain lobes

• Frontal lobe
• Temporal lobe
• Parietal lobe
• Occipital lobe

Cerebral sulci and gyri

The sulci are grooves or deep fissures which locate between the gyri that consist of a central core of white matter covered by a layer of grey matter( cerebral cortex).

Cerebral sulci

• Lateral sulcus
• Precentral sulcus
• Central sulcus
• Postcentral sulcus
• Parieto-occipital sulcus
• Occipitotemporal sulcus
• Calcarine sulcus
• Lunate sulcus
•

• Olfactory sulcus

• Rhinal sulcus
• Orbital sulcus
• Collateral sulcus
• Hippocampal sulcus
• Inferior temporal sulcus
• Superior temporal sulcus
• Superior frontal sulcus
• Inferior frontal sulcus
•

Calcarine sulcus

Olfactory sulcus

Gyri

• Supramarginal gyrus
• Angular gyrus
• Paraterminal gyrus
• Parahippocampal gyrus
• Dentate gyrus

THE WHITE MATTER OF THE CEREBRUM

It consists of the nerve fibers which lie deep to the cerebral cortex and connect the various parts of the cortex with each other and with the other parts of the CNS.