Question

Given below are comparing the effects of sympathetic and parasympathetic nervous systems for four features.
Which one feature is correctly described?
A. Feature- Salivary glands, Sympathetic nervous system- Stimulates secretion,Parasympathetic nervous system- Inhibits secretion.
B. Feature- Pupil of the eye, Sympathetic nervous system- Dilates, Parasympathetic nervous system- Constricts.
C. Feature- Heart rate, Sympathetic nervous system- Decreases, Parasympathetic nervous system- Increases.
D. Feature- Intestinal peristalsis, Sympathetic nervous system- Stimulates, Parasympathetic nervous system- Inhibits.

Answer 1

Hint: We know that the nervous system is the part of an animal's body that coordinates its behavior and transmits signals between different body areas. Sympathetic nervous system is known for stimulatory functions, while a parasympathetic nervous system is known for inhibitory functions.

Complete answer:
A: - Features: - SALIVARY GLAND Sympathetic nervous system – stimulates secretion, Parasympathetic nervous system – inhibits secretion.
Here it's saying that in a salivary gland sympathetic nervous system stimulates secretion and parasympathetic nervous systems stop it. But after studying and found that Saliva is produced and secreted by the salivary glands of the body. These glands are under the control of the autonomic nervous system, comprised of sympathetic and parasympathetic nerve fibres.The secretion of saliva (salivation) is mediated by parasympathetic stimulation; acetylcholine is the active neurotransmitter and binds to muscarinic receptors in the glands, leading to increased salivation.The sympathetic control of salivary production is through the superior cervical ganglion. Noradrenaline is released in response to sympathetic stimulation, acting upon alpha-and-beta adrenergic receptors. This results in decreased production of saliva.
B:- Feature:- Pupil of the eye Sympathetic nervous system – Dilates, Parasympathetic nervous system – Constricts
Again here under pupil of eye the response of sympathetic and parasympathetic nervous system are given as dilates and constricts respectively. But like we know the function of these nervous systems so accordingly Stimulation of the autonomic nervous system sympathetic, known for triggering "fight or flight" responses when the body is under stress, induces pupil dilation. Whereas stimulation of the parasympathetic system induces constriction and is known for "rest and digest" functions.
C: - Feature: - Heart rate Sympathetic nervous system –Decreases, Parasympathetic nervous system – increases.
As per the function of these nerves the sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate. The heart rate is slowed down in response to release of acetylcholine by the parasympathetic system. But in the above option it is just opposite.
D:- Feature:- Intestinal peristalsis Sympathetic nervous system- Stimulates , Parasympathetic nervous system- Inhibits.
The sympathetic and parasympathetic nervous systems have opposing effects. While the sympathetic nervous system slows down the intestinal peristalsis, the parasympathetic nervous system reacts conversely: it accelerates intestinal peristalsis.

Based on the description, the correct answer is (B).

Note:
The sympathetic nervous system is responsible for preparing the organism of a fight or escape. So It is active under stress once the threat is over, this system switches off and the effects of its stimulation are neutralized by the parasympathetic nervous system. The activity of human beings shows that the day releases the sympathetic nervous system operation, while the night prefers the parasympathetic nervous system.