What is Autonomic Nervous system?
Answers
Autonomic Nervous System- It is the which automatically develops the activities of the involuntary smooth muscles, cardiac muscles and glands means that which cannot be controlled by us is known as Autonomic Nervous System or ANS.
Significance of ANS- It plays an important role in maintaining the constant and internal environment that is known as homeostasis.
Division of Autonomic Nervous System
It is divided into two parts
1. Parasympathetic Nervous System
•The pupil is constrict.
•They decrease heart beat.
•They stimulates salivary gland.
•They take part in decrease of blood pressure.
2. Sympathetic Nervous System
•They dilate the pupil.
•They increase the heart beat rate.
•They inhibit the salivary gland.
•Also they increase the blood pressure.
NCERT based Answer for Class 11 Biology Students
Autonomic nervous system controls and coordinates the involuntary activities of the body. It is autonomous in the sense that it regulates the activities in which will power of the organism is not involved, e.g., secretion of digestive juices is under control of autonomic nervous system but the organism is not aware of it. The autonomic nervous system is divisible into two parts- parasympathetic and sympathetic nervous system.
Parasympathetic nervous system controls the "rest and digest" functions of the body. In other words it controls routine activities of body like digestion and excretion and conserves energy of the body. The specific responses are:
• decrease in heart rate
• constriction of bronchial tubes in the lungs and pupils in the eyes
• increase saliva and digestive juices production, regulates peristalsis of digestive tract.
• increase in urinary output
Sympathetic nervous system controls the body's "fight or flight responses" in emergency situations. During sympathetic nervous responses, the energy level of the body rises, and it becomes more alert. Some functions of the body system are slowed down; for example digestion, salivation and excretion. Following are the specific reactions of sympathetic nervous system:
• increase in the heart rate and
• dilation of bronchial tubes in the lungs and pupils in the eyes
• release of adrenaline from the adrenal gland
• conversion of glycogen to glucose in liver
• decrease in saliva and digestive juices production, slows down peristalsis in digestive tract.
• decrease in urinary output
Note: Sympathetic nervous system activates the adrenal medulla to release hormones- epinephrine and nor-epinephrine (called adrenaline rush) in the blood which elicit various changes in the body to elevate energy level. Once the perceived danger is gone, the parasympathetic nervous system takes over to counterbalance the effects of the sympathetic nervous system's responses.
Visit our website for purchasing XI & XII Complete Syllabus Video Lectures
https://concept-tutorials.teachable.com
