Autonomic nervous system

The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the fight-or-flight response.

1. AUTONOMIC NERVOUS SYSTEM By MD ALTAMASH AHMAD

2. AUTONOMIC NERVOUS SYSTEM The Autonomic Nervous System (or Visceral Nervous System ) is a part of Peripheral Nervous System that acts as a control system functioning unconsciously It is controlled by Medulla Oblongata and Hypothalamus It regulates the activities of cardiac muscle, smooth muscle and glands It is divided into two which works antagonistically : S ympathetic Nervous System Parasympathetic Nervous System

3. Autonomic Nervous System Certain involuntary responses to external stimuli are also mediated by the ANS. These include : constriction of the pupil in bright light and dilation of the pupil in dim light vasodilation of the skin and sweating in response to high core temperature vasoconstriction, “goose bumps,” and increased fat metabolism in response to low core temperature; the “flight or fight” response to threatening stimuli.

4. Sympathetic Nervous Syste m Neurotransmitter : Norepinephrine It allows body to function under stress The sympathetic nervous system's primary process is to stimulate the body's  fight-or-flight response . It is constantly active at a basic level to maintain homeostasis. Homeostasis is ability of body to maintain its internal environment like maintenance of optimum body temperature i.e. 37 degrees Celsius It activates in conditions like : exercise, excitement, emergency, and embarrassment

5. Fight or flight adaptive effects include:   increased cardiac activity, increased blood pressure, dilation of skeletal muscle blood vessels constriction of blood vessels in skin dilation of pupil in dark inhibition of gut and urinary bladder contractions increase in blood glucose and free fatty acid levels dilation of bronchial smooth muscle   secretion of viscous saliva sweating liver produces glucose to provide energy for muscle contraction.

6. Parasympathetic Nervous System Neurotransmitter : Acetylcholine It does maintenance function and relaxes the body The Parasympathetic Nervous System’s function is Rest and Digest It counterbalances the sympathetic function It get activated in conditions like : digestion , defecation, diuresis (urinating)

7. Parasympathetic activation results in: decreased cardiac activity secretion of watery saliva and stimulation of GI secretions contraction of urinary bladder increased insulin and glucagon secretion bronchiole constriction

8. Nicotinic Receptors Nicotinic Receptors  are ionotropic. Which means that when ACh binds to it, ions flow through it. It acts as a channel for positively charged ions, mainly sodium which passes the message. They're present in Neuromuscular junctions, brain and parasympathetic nervous system. Muscarinic Receptors Muscarinic Receptors , instead of becoming an ion channel for sodium, they use a G-Protein. When ACh binds to the receptor, this protein changes shape, which then allows it to pass various second messengers . They’re present in the brain, heart, smooth muscle, or in the Parasympathetic nervous system.