Question

The Sympathetic and parasympathetic nervous systems are antagonistic in their actions. Give any two examples in support of this statement.

Answer 1

Hint: Sympathetic and parasympathetic nervous systems are the part of the autonomic nervous system that behave antagonistic to each other on the body parts. The sympathetic nervous system is responsible for the “fight or flight” response during any potential danger. On the other hand, the parasympathetic nervous system inhibits the body from overworking and restores the body to a calm and composed state.

Complete answer:
Along with the central nervous system the peripheral nervous system lies inside the body. The autonomic nervous system (ANS) is part of peripheral nervous systems. The autonomic nervous system is regulated by a set of nerves which runs through the brain to the spinal cord and other organs. The various functions which are regulated by autonomic nervous system are respiration, cardiac cycle (the cardiac control center) and certain other reflex actions such as coughing, sneezing, swallowing and vomiting. Sympathetic and parasympathetic are the part of the autonomic nervous system. The sympathetic nervous system's works in order to stimulate the body's fight or flight response whereas on the other hand parasympathetic nervous system stimulates the body to rest-and-digest". Sympathetic nerves originate inside the vertebral column of the spinal cord in the intermediolateral cell column. The parasympathetic nervous system is composed of cells located in the brainstem and the sacral region of the spinal cord.
Sympathetic and parasympathetic nervous systems have antagonistic effects on the organs. It is due to release of different neurotransmitter activity in the brain by the central nervous system. In the Sympathetic nervous system the neurotransmitter releases adrenaline or nor-adrenaline whereas in the parasympathetic nervous system acetylcholine is released.

Therefore, they both work in antagonistic actions. If Sympathetic nervous system excites an organ, the parasympathetic usually inhibits it. Example:
1. The Sympathetic nervous system is responsible for accelerating the heartbeat whereas the parasympathetic nervous system is responsible for slowing down the heartbeat.
2. The Sympathetic nervous system inhibits the secretion of saliva from the salivary glands whereas parasympathetic nervous system stimulates saliva secretions.

Note: The autonomic nervous system comprises two different parts- the sympathetic and parasympathetic nervous system. The sympathetic nervous system activates the fight or flight response during a threat or danger, and the parasympathetic nervous system brings the body to a state of calm. Sympathetic system has shorter neuron pathways which makes their response time faster whereas a parasympathetic nervous system comparatively has longer neuron pathways having slower response time.