Neural Control and Coordination Test - 43

• Medulla oblongata encloses a cavity called fourth ventricle. 
• The medulla contains centres for controlling the functions of important organs e.g., cardiac centre (heart), respiratory centre, vasomotor centre (for regulating the diameter of blood vessels) and reflex centres (for swallowing, vomiting, peristalsis, salivation etc.)

The parasympathetic nervous system, or PSNS, is a part of the nervous system. The nervous system sends signals to and from different parts of the body via nerves. The PSNS is responsible for all the activities that take place when the body is at rest. During a period of flight and fight, the pupils dilate to allow us to see more clearly and make faster decisions. During rest and digest, the PSNS causes the pupils to constrict.

The autonomic nervous system controls the coordinated and involuntary movements of the body. The peristalsis of the intestine is an involuntary visceral movement which is controlled by the autonomic nervous system. 

D. Both B and C

Reason: The body coordination is maintained by the neuroendocrine system. It consists of the nervous system and the endocrine system. The nervous system controls the movement, etc. and the endocrine system regulates other physiological functions like - production of gametes, etc. Both of these systems are interconnected with each other.

C. $$O_2$$ and glucose

Reason: Brain is dependent on blood the supply for oxygen and glucose. It produces energy for the physiological reactions of brain.

A. Heart beat

Reason: Medulla of brain consists two regions affecting heart rate, cardiac inhibitory centre and cardiac accelerator centre. Sensory nerves originating from the accelerator centre and enter the SA node. Stimulation by these nerves which are part of sympathetic nervous system causes an increase in heartbeat.

• Medulla oblongata extends from the Pons Varolii above and is continuous with the spinal cord below. 
• Medulla oblongata receives and integrates signals from the spinal cord and sends resulting signals to the cerebellum and thalamus. 
• It contains centres that regulate heart rate, blood pressure, breathing, salivation, sneezing, vomiting and coughing.

Thus, the correct answer is 'Medulla oblongata'.

B. Two cerebral hemispheres

Reason: Cerebrum is the largest and most complex of all parts of the human brain. A deep cleft divides the cerebrum longitudinally into two halves, which are termed as the left and right cerebral hemispheres. The hemispheres are connected by a tract of nerve fibres called the corpus callosum.