Anatomy of brain

Anatomy of brain in brief

1. ANATOMY OF BRAIN SAYALI GUJJEWAR MPT I

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.

5. PARTS OF THE BRAIN

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.

13. Functions of brain

14. thalamus FUNCTIONS- Integrating centre where information is brought together. Ability to perceive pain.

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

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