2. INTRODUCTION
The human brain is the central organ of the human nervous system, and with the spinal cord makes
up the central nervous system.
It controls most of the activities of the body, processing, integrating, and coordinating the
information it receives from the sense organs, and making decisions as to the instructions sent to
the rest of the body.
Weight of the brain is 1500 grams i.e. about 2% of the total body weight. It is 167 mm long, 93 mm
high and 140 mm wide (approximately).
3. MENINGES OF THE BRAIN
DURA MATER-
Outermost, thickest and toughest membrane covering the brain.
ARACHNOID MATER-
Thin transparent membrane that loosely surrounds the brain.
PIA MATER-
Thin vascular membrane.
The extradural or epidural space is the space between the inner
aspect of skull bone and the endosteal layer of dura mater.
The subdural space is the space between the dura and arachnoid
maters.
The subarachnoid space is the space between the arachnoid and
the pia maters.
4. CEREBROSPINAL FLUID
The CSF is a modified tissue fluid.
It is contained in the ventricular system of the brain and in the subarachnoid space around the
brain and spinal cord.
The total quantity of CSF is about 150 ml.
FUNCTIONS OF THE CSF-
Decreases the sudden pressure or forces on delicate nervous tissue.
Nourishes the nervous tissue.
Cushions the brain within its solid vault.
6. BRAINSTEM
The brainstem consists of the medulla oblongata, the pons and the midbrain.
It connects the spinal cord to the cerebrum.
7. CEREBELLUM
Cerebellum controls the same side of the body.
FUNCTIONS-
Coordinates voluntary movements so that they are smooth, balanced and accurate.
Controls tone, posture and equilibrium.
8. FOURTH VENTRICLE
Cavity of hindbrain
Tent-shaped space between situated between the pons and upper part of medulla oblongata in
front and cerebellum behind.
9. CEREBRUM
Cerebrum is made up of two cerebral hemispheres which are separated by longitudinal fissure.
10. The two cerebral hemispheres are connected to each other by corpus callosum.
11. Each cerebral hemisphere is divided into 4 lobes- frontal, parietal, occipital and temporal.
12. Cerebral cortex is folded into gyri which are separated from each other by sulci.
15. hypothalamus
FUNCTIONS-
Endocrine control
Neurosecretion
General autonomic effect
Temperature regulation
Regulation of food and water intake
Sexual behaviour and reproduction
Biological clocks
Emotion, fear, rage, aversion, pleasure and
reward
16. Third ventricle
The third ventricle is a median cleft between the two thalami.
Secretes cerebrospinal fluid.
17. Lateral ventricle
The lateral ventricles are two irregular cavities situated one in each cerebral hemisphere.
Each lateral ventricle communicates with the third ventricle through an interventricular foramen
(foramen of Monroe).
Secretes cerebrospinal fluid.
18. Blood supply of brain/circle of willis
Anterior cerebral artery
Middle cerebral artery
Posterior cerebral artery- branch of basilar artery
Middle cerebral artery is main artery on superolateral surface of the cerebral cortex.
Anterior cerebral artery is chief artery on medial surface of the cerebral cortex.
Posterior cerebral artery is principal artery on inferior surface of the cerebral cortex.
Cerebellum is supplied by superior cerebellar artery, anterior inferior cerebellar artery and posterior
inferior cerebellar artery.
Branches of internal carotid artery