Briefly describe the structure of the Brain
Structure of brain: The brain is the central information processing organ of the body, The human brain is well protected by the skull. Inside the skull, cranial meninges cover the brain. These are tough tissue layers. Meninges consist of 3 layers which are as follows : The outermost – layer is the dura mater The middle layer is arachnoid The inner layer is pia mater. The brain can be divided into three major parts which are given below: forebrain midbrain hindbrain Forebrain: 1. Cerebrum consists two cerebral hemisphere on the dorsal surface. It is connected by a tract of nerve fibres called corpus callosum. Cerebral hemispheres are covered by the layer of cells called cerebral cortex and are thrown into prominent folds referred as grey matter. Inner part of the cerebral hemisphere is white matter. 2. Diencephlon is the posterior part of fore-brain. It consists of thalamus and hypothalamus. Thalamus is a major co-ordinating centre for sensory and motor signaling. It forms 80 % of diencephalon. Hypothalamus contains a number of centres which control many functions Like – hunger, thirst, sleep, sweating, body temperature and emotions (ii) Midbrain: It is located between the thalamus/ hypothalamus of the forebrain and pons of the hindbrain. It forms the brain stem with the hindbrain. Anterior part of mid-brain contains two cerebral peduncles, which controls the muscle of limbs and Posterior part of mid-brain in four optic lobs called corpora quadri gemiana i.e. two upper and two lower. (iii) Hindbrain: Hindbrain consists of pons. Cerebellum and medulla of longata. Pons is present below the midbrain and upper side of medulla oblongata. It possesses pneumotaxic area of respiratory centre. Cerebellum is the 2nd largest part of brain, which lies behind cerebrum and provides the additional space for many neuron and maintains equilibrium or posture of the body. Medulla oblongata lies below cerebellum and continues into the spinal-cord. It contains a respiratory centre for regulating breatheing, Cardiac centre for regulating heartbeat and blood pressure, and also has reflex centre for swallowing, coughing, sneezing, etc.
