Autonomic Nervous System Overview

The part of the nervous system that controls involuntary bodily functions such as heart rate, digestion, and breathing.

The state of balance and stability in the internal environment of the body.

The division of the ANS responsible for preparing the body for 'fight or flight' responses.

The physiological processes by which the body maintains its internal environment within a narrow range, despite external changes.

The division of the ANS responsible for calming the body and restoring energy reserves.

The process by which the nervous system receives and processes information from the environment.

The process by which the nervous system sends signals to muscles and glands to control bodily functions.

The principle that the ANS operates independently of conscious control.

The ability of the ANS to adapt to changing conditions and maintain homeostasis.

A complex network of neurons in the digestive system that regulates digestion, motility, and secretion.

The autonomic nervous system (ANS) regulates involuntary physiological processes. Responsible for controlling things like heart rate, digestion, respiration, and pupil dilation.

The sympathetic nervous system is responsible for the 'fight or flight' response, preparing the body for stressful situations.

The parasympathetic nervous system is associated with 'rest and digest', helping the body conserve energy and recover after stress.

The enteric nervous system is a specialized network of neurons in the digestive tract, controlling digestion and gut motility.

Sympathetic preganglionic neurons originate in the intermediolateral horn of the spinal cord (T1-L2).

Sympathetic postganglionic neurons release mainly noradrenaline (NA) as a neurotransmitter, except for sweat glands and piloerector muscles which use acetylcholine (ACh).

Parasympathetic preganglionic neurons originate in the brainstem (cranial nerves III, VII, IX, X) and sacral spinal cord (S2-S4).

Parasympathetic postganglionic neurons release acetylcholine (ACh) as a neurotransmitter.

Adrenergic receptors are G protein-coupled receptors found on sympathetic target organs. They mediate the effects of adrenaline and noradrenaline.

Muscarinic receptors are G protein-coupled receptors found on parasympathetic target organs, mediating the effects of acetylcholine.

Signals from body tissues, like heart rate or stomach fullness, that are detected by the nervous system.

Specialized nerve cells that detect sensory information from internal organs and tissues.

The brain region that receives most signals from internal organs, helping to control autonomic functions.

Rapid, automatic responses triggered by sensory input from internal organs, like changes in heart rate or digestive activity.

Brain areas involved in coordinating widespread changes in autonomic activity, like during stress or relaxation.

A brain region involved in processing emotions, behaviors, and sensory information, including signals from internal organs.

A brain region involved in processing fear and threat, and sending signals to the autonomic nervous system.

A brain region involved in regulating basic bodily functions like hunger, thirst, and temperature control, also influencing the autonomic nervous system.

The process of integrating sensory information from internal organs with other senses, memories, and emotions to create complex responses.

The coordinated activity of various brain regions, such as the hypothalamus, amygdala, and insular cortex, to regulate widespread changes in autonomic activity.

The enteric nervous system is a complex network of neurons located within the walls of the digestive tract. It controls digestion, motility (movement), and secretion.

The myenteric plexus is a network of nerves located between the layers of smooth muscle in the digestive tract. It regulates muscle contractions for peristalsis.

The submucosal plexus is located in the submucosa layer of the digestive tract. It regulates secretion, blood flow, and absorption.

Sensory neurons in the myenteric plexus detect the degree of stretch in smooth muscles, providing information on the amount of food moving through the digestive tract.

Sensory neurons in the submucosal plexus monitor the chemical composition (contents) of the lumen, the inside of the digestive tract.

Visceromotor neurons control the smooth muscle contractions and secretions of the digestive tract, coordinating the movement of food.

Secretomotor neurons stimulate the release of mucus, enzymes, and other secretions into the lumen of the digestive system.

Interneurons in the enteric nervous system connect sensory and motor neurons, creating a complex network that integrates information and coordinates responses.

The enteric nervous system functions largely independently of the brain and spinal cord, making it a true 'mini brain' capable of self-regulation.

The brain and spinal cord still provide some regulatory input to the enteric nervous system through the parasympathetic (via the vagus nerve) and sympathetic nervous systems.