Test: Central Neural System (NCERT) - NEET MCQ

In the given figure, structures A and D are brain and spinal cord respectively, and these structures belong to central neural system. Structures 'B' and 'C' are the nerves arising from brain and spinal cord respectively and thus they belong to peripheral neural system.

Hypothalamus is a part of fore brain. It is the thermoregulatory centre of the brain. It keeps body temperature at roughly 37ºC by means of a complex thermostat system.

Brain performs a number of activities like it controls the functions of our organs and also provides ualities of mind-learning, reasoning and memory. For all the activitites brain needs a large and constant supply of energy. The brain accounts for 20% of body's consumption of oxygen and 15% of consumption of blood glucose. If brain is deprived of oxygen for just 5 minutes, it becomes permanently damaged. Mental confusion occurs if brain is deprived of glucose.

Sensory information like touch, temperature and pain from trunk and limbs is carried to sensory relay nuclei in thalamus. It is from the thalamus that the third order neuron goes to sensory cortex which is situated in the frontal lobe (fore brain).

The dorsal portion of the midbrain consists of four rounded lobes called quadrigemina.

Meninges are the three connective tissue membranes that enclose the brain and spinal cord. Piamater is the innermost membrane which is thin, delicate and vascular. The next membrane is arachnoid which is thin and webby. Duramater is the outermost membrane which is tough dense and fibrous in nature.

Pons is located in front of the cerebelum below the mid brain and above the medulla oblongata. It consists of nerve fibres that connect the two hemispheres of cerebellum.

The mid brain, pons varolli and medulla oblongata (both of which are parts of hind brain) are collectively termed as brain that connects the fore brain and spinal cord.

• The hindbrain comprises of the pons, the medulla oblongata and the cerebellum.
• The hippocampus is present in the forebrain and is a part of the limbic system, which controls emotional reactions.

Hypothalamus is a part of fore brain that controls the urge for eating and drinking.

• The medulla oblongata is present in the hindbrain.
• It controls important functions such as respiration, cardiovascular reflexes and gastric secretions.
• The forebrain controls the circadian rhythm.

Part 'C' is medulla oblongata that controls breathing.

Regulation of gastric secretion is also done by medulla oblongata.

Cerebellar hemispheres are the largest regions of the cerebellum. The cerebellar hemispheres are two divisions of the cerebellum on either side of the vermis. They are functionally subdivided into lateral and medial portions. It is a part of the hindbrain. The arborvitae is the cerebellar white matter, so-called for its branched, tree-like appearance. In resembles like a fern and is present in both cerebellar hemispheres. It brings sensory and motor information to and from the cerebellum.

(A) Medulla oblongata - (i) Involuntary breathing movements
(E) Cerebellum - (ii) Accurate voluntary movements
(D) Cerebral hemispheres - (iii) Seat of memory