Neural Control and Coordination Test - 20

The part labelled as P is the forebrain which is mainly involved in the interpretation of information and cognitive skills. 

The axon of the neuron secretes the substance named neurotransmitter to communicate with next dendrite. They are stored within synaptic vessicles. Neurotransmitters help in the chemical transmission of impulse and they may be excitatory or inhibitory.

• Sensory receptors are nerve receptors that are present in different organs of a body that respond to stimuli in the internal or the external environment of an organism. Olfactory receptors, thermoreceptors, gustatory receptors, photoreceptors are sensory receptors. 
• Olfactory receptors also called odorant receptors are present in the nose. They transmit odours from nose to brain and helps recognise different types of smell.
• Thermoreceptors are non-specialised sensory neurons that connect the skin to the hypothalamic region of the brain. These nerves, code for temperature changes that are detected by the brain. Further, required thermoregulation is processed by the hypothalamus.
• Gustatory receptors also called taste receptors are present in the tongue. They detect five types of taste, viz; sweet, sour, bitter, salty and savoury.
• Photoreceptors are present in the eyes. There are two types of photoreceptors, i.e, rods and cones. They contain coloured pigments which help differentiate between colours. 

Photoreceptors are the receptors which are stimulated by light and another form of electromagnetic radiations. They are present in the retina of eyes. 

The sympathetic branch of our autonomic nervous system originates in the spinal cord. It goes into action to prepare the body for physical or mental activity. Its general action is to mobilize the body in a fight response. It increases muscle blood flow and tension, dilates pupils, accelerates heart rate and respiration, and increases perspiration and arterial blood pressure. To conserve and concentrate energy, it slows down digestive activity.

The hindbrain or rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates. It includes the medulla, pons and cerebellum. Together they support vital bodily processes.

Correct Option: A
Explanation:

• The parasympathetic nervous system controls the homoeostasis of the body and is responsible for "rest and digest" response.
• It controls involuntary functions of internal organs such as heart rate, digestion, urination, eyes, etc.
• Parasympathetic nerves are known to control the constriction of pupils in response to bright light. Thus increasing the activity of iris.
• Also, controls the gut for digestion and urinary bladder.
• The sympathetic nervous system originates from the spinal cord in the thoracic and lumbar regions and functions to control adrenal gland, sweat glands, pancreas, lacrimal gland.

Hence, the parasympathetic nervous system increases the activity of the guts, iris, and urinary bladder.