PART - 2 - Unit V : CH - 18 Neural Control and Coordination — BIOLOGY STD 11 Science — Question

(a) Brain: It is covered by three membranes which are called Duramater, Arachnoid and Piamater respectively. The brain is divided into three parts:
(i) Forebrain (ii) Midbrain (iii) Hindbrain,
(i) Forebrain: Made up of cerebrum, thalamus and hypothalamus. The cerebrum is divided vertically into two hemispheres, which are connected by the corpus callosum. Hypothalamus, an important part of the forebrain, controls body temperature, eating and drinking etc. The inner part of the cerebral hemispheres and the organised structures located deeper together form a complex structure, which is called the limbic system and it is related to smell, reflex actions, control of sexual behaviour, expression of emotions and motivation.
(ii) Midbrain: It is located between the thalamus/ hypothalamus of the forebrain and the pons of the hindbrain. The upper part of the midbrain is made up of four lobe-like projections called corpora quadrigemina. The midbrain is related to receptor and integration and integrated visual fibre and auditory interoceptive functions.
(iii) Hindbrain: Hindbrain is made up of pons, cerebellum and medulla. The pons is made up of fibrous pathways that connect different parts of the brain. The surface of the cerebellum is insulated which provides additional space to the neurons. The medulla oblongata is connected to the spinal cord. The medulla oblongata contains control centres for respiration, cardiovascular reflexes and secretion of digestive juices.