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Autonomic nervous system

 

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Autonomic nervous system



 
 
The autonomic nervous system (ANS) (or visceral nervous system) is the part of the peripheral nervous system
Peripheral nervous system

The peripheral nervous system resides or extends outside the central nervous system , which consists of the brain and spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs....
 that acts as a control system
Control system

A control system is a device or set of devices to manage, command, direct or regulate the behavior of other devices or systems.There are two common classes of control systems, with many variations and combinations: logic gate, and feedback or linear controls....
, maintaining homeostasis
Human homeostasis

Human homeostasis refers to the body's ability to refer physiologically its milieu interieur to ensure its stability in response to fluctuations in the outside environment and the weather....
 in the body. These activities are generally performed without conscious control. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination), and sexual arousal
Sexual arousal

Sexual arousal is the the arousal of sexual desires in preparation for sexual behavior....
. Whereas most of its actions are involuntary, some, such as breathing, work in tandem with the conscious mind.

It can be divided by subsystems into the parasympathetic nervous system
Parasympathetic nervous system

The parasympathetic nervous system is a division of the autonomic nervous system , along with the sympathetic nervous system and enteric nervous system ....
 and sympathetic nervous system
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
.






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The autonomic nervous system (ANS) (or visceral nervous system) is the part of the peripheral nervous system
Peripheral nervous system

The peripheral nervous system resides or extends outside the central nervous system , which consists of the brain and spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs....
 that acts as a control system
Control system

A control system is a device or set of devices to manage, command, direct or regulate the behavior of other devices or systems.There are two common classes of control systems, with many variations and combinations: logic gate, and feedback or linear controls....
, maintaining homeostasis
Human homeostasis

Human homeostasis refers to the body's ability to refer physiologically its milieu interieur to ensure its stability in response to fluctuations in the outside environment and the weather....
 in the body. These activities are generally performed without conscious control. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination), and sexual arousal
Sexual arousal

Sexual arousal is the the arousal of sexual desires in preparation for sexual behavior....
. Whereas most of its actions are involuntary, some, such as breathing, work in tandem with the conscious mind.

It can be divided by subsystems into the parasympathetic nervous system
Parasympathetic nervous system

The parasympathetic nervous system is a division of the autonomic nervous system , along with the sympathetic nervous system and enteric nervous system ....
 and sympathetic nervous system
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
. It can also be divided functionally, into its sensory and motor systems.

The enteric nervous system
Enteric nervous system

The enteric nervous system is a subdivision of the Peripheral Nervous System, that directly controls the gastrointestinal system.It is derived from neural crest....
 is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system.

Anatomy


The reflex arcs of the ANS comprise a sensory (afferent) arm, and a motor (efferent or effector) arm. Only the latter is shown in the illustration.

Sensory neurons


The sensory arm is made of “primary visceral sensory neurons” found in the peripheral nervous system (PNS), in “cranial sensory ganglia”: the geniculate, petrosal and nodose ganglia, appended respectively to cranial nerves
Cranial nerves

Cranial nerves are nerves that emerge directly from the brain stem in contrast to spinal nerves which emerge from segments of the spinal cord. Although thirteen cranial nerves in human anatomy fit this description, twelve are conventionally recognized....
 VII, IX and X. These sensory neurons monitor the levels of carbon dioxide, oxygen and sugar in the blood, arterial pressure and the chemical composition of the stomach and gut content. (They also convey the sense of taste, a conscious perception). Blood oxygen and carbon dioxide are in fact directly sensed by the carotid body
Carotid body

The carotid body is a small cluster of chemoreceptors and supporting cells located near the fork of the carotid artery .The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of oxygen, but also of carbon dioxide....
, a small collection of chemosensors at the bifurcation of the carotid artery, innervated by the petrosal (IXth) ganglion.

Primary sensory neurons project (synapse) onto “second order” or relay visceral sensory neurons located in the medulla oblongata, forming the nucleus of the solitary tract (nTS), that integrates all visceral information. The nTS also receives input from a nearby chemosensory center, the area postrema
Area postrema

The area postrema is a part of the brain that controls vomiting. It was discovered in 1953 by Utah Pharmacologists Herbert L. Borison and S. C. Wang ....
, that detects toxins in the blood and the cerebrospinal fluid
Cerebrospinal fluid

Cerebrospinal fluid , Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space and the ventricular system around and inside the brain....
 and is essential for chemically induced vomiting and conditional taste aversion (the memory that ensures that an animal which has been poisoned by a food never touches it again). All these visceral sensory informations constantly and unconsciously modulate the activity of the motor neurons of the ANS.

Motor neurons


Motor neurons of the ANS are also located in ganglia of the PNS, called “autonomic ganglia”. They belong to three categories with different effects on their target organs (see below “Function”): sympathetic, parasympathetic and enteric.

Sympathetic ganglia are located in two sympathetic chains close to the spinal cord: the prevertebral and pre-aortic chains. Parasympathetic ganglia, in contrast, are located in close proximity to the target organ: the submandibular ganglion
Submandibular ganglion

The submandibular ganglion is part of the human autonomic nervous system. It is one of four parasympathetic ganglia of the head and neck. ....
 close to salivatory glands, paracardiac ganglia close to the heart etc... Enteric ganglia, which as their name implies innervate the digestive tube, are located inside its walls and collectively contain as many neurons as the entire spinal cord, including local sensory neurons, motor neurons and interneurons. It is the only truly autonomous part of the ANS and the digestive tube can function surprisingly well even in isolation. For that reason the enteric nervous system
Enteric nervous system

The enteric nervous system is a subdivision of the Peripheral Nervous System, that directly controls the gastrointestinal system.It is derived from neural crest....
 has been called “the second brain”.

The activity of autonomic ganglionic neurons is modulated by “preganglionic neurons” (also called improperly but classically "visceral motoneurons") located in the central nervous system. Preganglionic sympathetic neurons are in the spinal cord, at thoraco-lumbar levels. Preganglionic parasympathetic neurons are in the medulla oblongata (forming visceral motor nuclei: the dorsal motor nucleus of the vagus nerve (dmnX), the nucleus ambiguus
Nucleus ambiguus

The nucleus ambiguus is a region of histology disparate cell s located just Dorsum to the inferior olivary nucleus in the Human anatomical terms#Anatomical directions portion of the upper medulla oblongata....
, and salivatory nuclei) and in the sacral spinal cord. Enteric neurons are also modulated by input from the CNS, from preganglionic neurons located, like parasympathetic ones, in the medulla oblongata (in the dmnX).

The feedback from the sensory to the motor arm of visceral reflex pathways is provided by direct or indirect connections between the nucleus of the solitary tract and visceral motoneurons.

Function

Sympathetic and parasympathetic divisions typically function in opposition to each other. But this opposition is better termed complementary in nature rather than antagonistic. For an analogy, one may think of the sympathetic division as the accelerator and the parasympathetic division as the brake. The sympathetic division typically functions in actions requiring quick responses. The parasympathetic division functions with actions that do not require immediate reaction. Consider sympathetic as "fight or flight
Fight or Flight

Fight or Flight may refer to:* Fight-or-flight response, the biological response of animals to acute stress* Fight or Flight , an album by the British rock band Turin Brakes...
" and parasympathetic as "rest and digest".

However, many instances of sympathetic and parasympathetic activity cannot be ascribed to "fight" or "rest" situations. For example, standing up from a reclining or sitting position would entail an unsustainable drop in blood pressure if not for a compensatory increase in the arterial sympathetic tonus. Another example is the constant, second to second modulation of heart rate by sympathetic and parasympathetic influences, as a function of the respiratory cycles. More generally, these two systems should be seen as permanently modulating vital functions, in usually antagonistic fashion, to achieve homeostasis. Some typical actions of the sympathetic and parasympathetic systems are listed below.

Sympathetic nervous system
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....

Promotes a "fight or flight" response, corresponds with arousal and energy generation, and inhibits digestion.

  • Diverts blood flow away from the gastro-intestinal (GI) tract and skin
    Skin

    The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
     via vasoconstriction.
  • Blood flow to skeletal muscle
    Skeletal muscle

    They generally contract voluntarily , although they can contract involuntarily through Reflex action. The whole muscle is wrapped in a special type of connective tissue, epimysium....
    s, the lung
    Lung

    The lung is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart....
     is not only maintained, but enhanced (by as much as 1200%, in the case of skeletal muscles).
  • Dilates bronchioles of the lung, which allows for greater alveolar oxygen exchange.
  • Increases heart rate
    Heart rate

    Heart rate is a measure of the number of heart beats per minute . The average resting human heart rate is about 70 bpm for adult males and 75 bpm for adult females....
     and the contractility
    Contractility

    Myocardial contractility is a term used in physiology to describe the performance of cardiac muscle.Contractility is often defined as the intrinsic ability of a cardiac muscle fibre to contract at a given fibre length....
     of cardiac cells (myocytes), thereby providing a mechanism for the enhanced blood flow to skeletal muscles.
  • Dilates pupils and relaxes the lens, allowing more light to enter the eye
    Eye

    Eyes are Organ that detect light, and send signals along the optic nerve to the visual system and other areas of the brain. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system....
    .
  • Provides vasodilation for the coronary vessels of the heart
    Heart

    The heart is a muscle organ in all vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods....
    .
  • Inhibits peristalsis.


Parasympathetic nervous system
Parasympathetic nervous system

The parasympathetic nervous system is a division of the autonomic nervous system , along with the sympathetic nervous system and enteric nervous system ....


Promotes a "rest and digest" response, promotes calming of the nerves return to regular function, and enhances digestion.

  • Dilates blood vessels leading to the GI tract, increasing blood flow. This is important following the consumption of food, due to the greater metabolic demands placed on the body by the gut.


  • The parasympathetic nervous system can also constrict the bronchiolar diameter when the need for oxygen has diminished.


  • Dedicated cardiac branches of the Vagus and thoracic Spinal Accessory
    Accessory nerve

    In anatomy, the accessory nerve is a nerve that controls specific muscles of the neck. As a part of it was formerly believed to originate in the brain, it is considered a cranial nerve....
     nerves impart Parasympathetic control of the Heart
    Heart

    The heart is a muscle organ in all vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods....
     or Myocardium.


  • During accommodation, the parasympathetic nervous system causes constriction of the pupil and lens.


  • The parasympathetic nervous system stimulates salivary gland secretion, and accelerates peristalsis
    Peristalsis

    Peristalsis is the rhythmic contraction of smooth muscles to propel contents through the digestive tract. The word is derived from New Latin and comes from the Greek language peristaltikos, peristaltic, from peristellein, "to wrap around," and stellein, "to place."...
    , so, in keeping with the rest and digest functions, appropriate PNS activity mediates digestion of food and indirectly, the absorption of nutrients.


  • Is also involved in erection of genitals, via the pelvic splanchnic nerves
    Pelvic splanchnic nerves

    Pelvic splanchnic nerves or nervi erigentes are splanchnic nerves that arise from sacral spinal nerves sacral spinal nerve 2, sacral spinal nerve 3, sacral spinal nerve 4 to provide parasympathetic innervation to the hindgut....
     2–4.


Neurotransmitters and pharmacology


At the effector organs, sympathetic ganglionic neurons release noradrenaline (norepinephrine), along with other cotransmittors such as ATP
Adenosine triphosphate

This article is about the chemical used by cells as an energy carrier. For other uses, see ATP .Adenosine-5'-triphosphate is a multifunctional nucleotide, and plays an important role in cell biology as a coenzyme that is the "molecule unit of currency" of intracellular energy transfer....
, to act on adrenergic receptors, with the exception of the sweat glands and the adrenal medulla:

  • Acetylcholine
    Acetylcholine

    The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including homo sapiens....
     is the preganglionic neurotransmitter for both divisions of the ANS, as well as the postganglionic neurotransmitter of parasympathetic neurons. Nerves that release acetylcholine are said to be cholinergic. In the parasympathetic system, ganglionic neurons use acetylcholine as a neurotransmitter, to stimulate muscarinic receptors.
  • At the adrenal cortex
    Adrenal cortex

    Situated along the perimeter of the adrenal gland, the adrenal cortex mediates the stress response through the production of mineralocorticoids and glucocorticoids, including aldosterone and cortisol respectively....
    , there is no postsynaptic neuron. Instead the presynaptic neuron releases acetylcholine to act on nicotinic receptors.
  • Stimulation of the adrenal medulla
    Adrenal medulla

    The adrenal medulla is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex.Basic...
     releases adrenaline (epinephrine) into the bloodstream which will act on adrenoceptors, producing a widespread increase in sympathetic activity.


The following table reviews the actions of these neurotransmitters as a function of their receptors.

Circulatory system
Circulatory system

The circulatory system is an organ that moves nutrients, gases, and wastes to and from cells to help fight diseases and help stabilize body temperature and pH to maintain homeostasis....


Heart
Heart

The heart is a muscle organ in all vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods....
|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | cardiac output
Cardiac output

Cardiac output is the volume of blood being pumped by the heart, in particular by a ventricle in a minute. This is measured in dm3 min-1 ....
 || ß1, (ß2): increases || M2: decreases |- | SA node: heart rate (chronotropic
Chronotropic

Chronotropic effects are those that change the heart rate.Chronotropic drugs may change the heart rate by affecting the nerves controlling the heart, or by changing the rhythm produced by the sinoatrial node....
) || ß1, (ß2) : increases || M2: decreases |- | Atrial cardiac muscle
Cardiac muscle

Cardiac muscle is a type of involuntary sarcomere muscle found in the walls of the heart, specifically the wikt:myocardium. Cardiac muscle cells are known as cardiac myocytes ....
: contractility (inotropic) || ß1, (ß2): increases || M2: decreases |- | Ventricular cardiac muscle
Cardiac muscle

Cardiac muscle is a type of involuntary sarcomere muscle found in the walls of the heart, specifically the wikt:myocardium. Cardiac muscle cells are known as cardiac myocytes ....
 || ß1, (ß2):
increases contractility (inotropic)
increases cardiac muscle automaticity || --- |- | at AV node || ß1:
increases conduction
increases cardiac muscle automaticity || M2:
decreases conduction
Atrioventricular block
Atrioventricular block

An atrioventricular block is a type of heart block involving impairment of the conduction between the atria and ventricles of the heart. It usually involves the atrioventricular node, but it can involve other structures....
  |- |}

Blood vessels
|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | vascular smooth muscle
Vascular smooth muscle

Vascular smooth muscle refers to the particular type of smooth muscle found within, and composing the majority of the wall of blood vessels....
 || a: contracts; ß2: relaxes || M3: relaxes |- | renal artery
Renal artery

The renal arteries normally arise off the side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood....
 || a1: constricts|| --- |- | larger coronary arteries || a1 and a2: constricts || --- |- | smaller coronary arteries || ß2:dilates || --- |- | arteries to viscera || a: constricts|| --- |- | arteries to skin
Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
 || a: constricts|| --- |- | arteries to brain
Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
 || a1: constricts || --- |- | arteries to erectile tissue
Erectile tissue

Erectile tissue is tissue in the body that can become erect, usually by becoming engorged with blood....
 || a1: constricts|| M3: dilates |- | arteries to salivary gland
Salivary gland

The salivary glands in mammals are exocrine glands that produce saliva. They also secrete amylase, an enzyme that breaks down starch into glucose. In other organisms such as Insecta, salivary glands are often used to produce biologically important proteins like silk or glues, and fly salivary glands contain polytene chromosomes that have been usefu...
s || a: constricts|| M3: dilates |- | hepatic artery
Hepatic artery

Hepatic artery can refer to:* Common hepatic artery * Hepatic artery proper ...
 || ß2: dilates|| --- |- | arteries to skeletal muscle
Skeletal muscle

They generally contract voluntarily , although they can contract involuntarily through Reflex action. The whole muscle is wrapped in a special type of connective tissue, epimysium....
 || ß2: dilates|| --- |- | Vein
Vein

In the circulatory system, veins are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary vein and umbilical veins, both of which carry oxygenated blood....
s || a1 and a2 : constricts
ß2: dilates || --- |- |}

Other
|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | platelets || a2: aggregates || --- |- | mast cells - histamine
Histamine

Histamine is a biogenic amine involved in local immune system as well as regulating physiological function in the gut and acting as a neurotransmitter....
 || ß2: inhibits || --- |- |}

Respiratory system
Respiratory system

A respiratory system?s function is to allow gas exchange. The space between the alveoli and the capillaries, the anatomy or structure of the exchange system, and the precise physiological uses of the exchanged gases vary depending on the organism....

|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | smooth muscles of bronchioles || ß2: relaxes (major contribution)
a1
Alpha-1 adrenergic receptor

The alpha-1 adrenergic receptor is an adrenergic receptor with the primary effect of vasoconstriction....
: contracts (minor contribution) || M3: contracts |- |}

The bronchioles have no sympathetic innervation, but are instead affected by circulating adrenaline

Nervous system
Nervous system

The nervous system is a Neural network of specialized cells that communicate information about an animal's surroundings and itself. It processes this information and causes reactions in other parts of the body....

|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | Pupil dilator muscle || a1
A1 receptor

The adenosine A1 receptor is one member of the adenosine receptor group of G protein-coupled receptors with adenosine as endogenous ligand....
: contracts
(causes mydriasis
Mydriasis

Mydriasis is an excessive dilation of the pupil due to disease, Physical trauma, or the use of drugs. Normally, the pupil dilates in the dark and constriction in the light to improve vividity at night and to protect the retina from sunlight damage during the day....
) || M3: relaxes
(causes miosis
Miosis

Miosis is constriction of the pupil of the eye. This is a normal response to an increase in light but can also be associated with certain pathological conditions, microwave radiation exposure and certain drugs....
) |- | Ciliary muscle
Ciliary muscle

The ciliary muscle is a muscle in the eye that controls the eye's accommodation for viewing objects at varying distances....
 || ß2: relaxes
(causes long-range focus) || M3: contracts
(causes short-range focus) |- |}

Digestive system

|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | salivary glands: secretions || ß: stimulates viscous, amylase
Amylase

Amylase is an enzyme that breaks starch down into sugar. Amylase is present in human saliva, where it begins the chemical process of digestion....
 secretions
a1: stimulates potassium
Potassium

Potassium is a chemical element. It has the symbol K , atomic number 19, and atomic mass 39.0983. Potassium was first isolated from potash, hence the name....
 cation || M3: stimulates watery secretions |- | lacrimal glands (tears) || ß2: Protein secretion || M3: increases |- | kidney
Kidney

The kidneys are Organ that have numerous biological roles. Their primary role is to maintain the homeostasis balance of bodily fluids by filtering and secreting Metabolomics#Metabolitess and minerals from the blood and excreting them, along with water , as urine....
 (renin
Renin

Renin , also known as Angiotensinogenase, is a circulating enzyme that participates in the body's renin-angiotensin system that mediates extracellular volume , and arterial vasoconstriction....
) || ß1: secretes || --- |- | parietal cells || --- || M1: Gastric acid
Gastric acid

Gastric acid is one of the main secretions of the stomach, together with several enzymes and intrinsic factor. Chemically it is an acid solution with a pH of 1 to 2 in the stomach lumen , consisting mainly of hydrochloric acid , and large quantities of potassium chloride and sodium chloride ....
 secretion |- | liver
Liver

The liver is a vital organ present in vertebrates and some other animals; it has a wide range of functions, a few of which are detoxification, protein synthesis, and production of biochemicals necessary for digestion....
 || a1, ß2: glycogenolysis
Glycogenolysis

Glycogenolysis is the catabolism of glycogen by removal of a glucose monomer through cleavage with inorganic phosphate to produce glucose-1-phosphate....
, gluconeogenesis
Gluconeogenesis

Gluconeogenesis is a metabolic pathway that results in the generation of glucose from non-carbohydrate carbon substrates such as lactic acid, glycerol, and glucogenic amino acids....
  || --- |- | adipose cells || ß1, ß3: stimulates lipolysis
Lipolysis

Lipolysis is the breakdown of fat stored in fat cells. During this process, free fatty acids are released into the bloodstream and circulate throughout the body....
  || --- |- | GI tract (smooth muscle
Smooth muscle

Smooth muscle is a type of non-striated muscle, found within the tunica media layer of large and small arteries and veins, the urinary bladder, uterus, male and female reproductive tracts, gastrointestinal tract, respiratory tract, the ciliary muscle, and iris of the eye....
) motility || a1, a2, ß2: decreases || M3, (M1) : increases |- | sphincters of GI tract || a1 , a2 , ß2: contracts || M3: relaxes |- | glands of GI tract || no effect || M3: secretes |- |}

Endocrine system
Endocrine system

The endocrine system is a system of small organs that involve the release of extracellular signaling molecules known as hormones. The endocrine system is instrumental in regulating metabolism, human development , and tissue and also plays a part in determining Mood ....

|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | pancreas
Pancreas

The pancreas is a gland Organ in the digestive system and endocrine system of vertebrates. It is both an endocrine gland , as well as an exocrine gland, secreting pancreatic juice containing Digestion enzymes that pass to the small intestine....
 (islets
Islets of Langerhans

The islets of Langerhans are the regions of the pancreas that contain its endocrine cells. Discovered in 1869 by German pathological anatomist Paul Langerhans, the islets of Langerhans constitute approximately 1 to 2% of the mass of the pancreas....
) || a2: decreases secretion from beta cell
Beta cell

Beta cells are a type of cell in the pancreas in areas called the islets of Langerhans. They make up 65-80% of the cells in the islets....
s, increases secretion from alpha cell
Alpha cell

Alpha cells are endocrine system cell s in the islets of Langerhans of the pancreas. They make up 15-20% of the cells in the islets. They are responsible for synthesizing and secreting the peptide hormone glucagon, which elevates the glucose levels in the blood....
s || M3 increases stimulation from alpha cell
Alpha cell

Alpha cells are endocrine system cell s in the islets of Langerhans of the pancreas. They make up 15-20% of the cells in the islets. They are responsible for synthesizing and secreting the peptide hormone glucagon, which elevates the glucose levels in the blood....
s and beta cell
Beta cell

Beta cells are a type of cell in the pancreas in areas called the islets of Langerhans. They make up 65-80% of the cells in the islets....
s |- | adrenal medulla
Adrenal medulla

The adrenal medulla is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex.Basic...
 || N
Nicotinic acetylcholine receptor

Nicotinic acetylcholine receptors, or nAChRs, are cholinergic receptors that form ligand-gated ion channels in the plasma membranes of certain neurons....
 (nicotinic ACh
Acetylcholine

The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including homo sapiens....
 receptor): secretes epinephrine
Epinephrine

Epinephrine is a hormone and neurotransmitter.Epinephrine increases the "fight or flight" response of the Sympathetic nervous system of the autonomic nervous system....
 and norepinephrine
Norepinephrine

Norepinephrine or noradrenaline is a catecholamine with dual roles as a hormone and a neurotransmitter.As a stress hormone, norepinephrine affects parts of the brain where attention and responding actions are controlled....
 || --- |- |}

Urinary system
Urinary system

The urinary system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the urinary bladder, and the urethra....

|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | Detrusor urinae muscle? of bladder
Urinary bladder

In anatomy, the urinary bladder is a solid, muscle, and distensible organ that sits on the pelvic floor in mammals. It is the organ that collects urine excreted by the kidneys prior to disposal by urination....
 wall || ß2: relaxes || M3: contracts |- | ureter
Ureter

In human anatomy, the ureters are muscular ducts that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long....
 || a1: contracts || relaxes |- | sphincter
Sphincter

A sphincter is a structure, usually a circular muscle, that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning....
 || a1: contracts; ß2 relaxes || M3: relaxes |- |}

Reproductive system
Reproductive system

The reproductive system is a system of Organ within an organism which work together for the purpose of reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system....

|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | uterus
Uterus

The uterus is a major female hormone-responsive reproductive sex organ of most mammals, including humans. It is within the uterus that the fetus develops during gestation....
 || a1: contracts (pregnant)
ß2: relaxes (non-pregnant) || --- |- | genitalia || a: contracts (ejaculation
Ejaculation

Ejaculation is the ejecting of semen from the penis, and is usually accompanied by orgasm. It is usually the result of sexual stimulation. Rarely, it is due to prostatic disease....
) || M3: erection |- |}

Integumentary system
Integumentary system

The integumentary system is the organ system that protects the body from damage, comprising the skin and its appendages. The integumentary system has a variety of functions; it may serve to waterproof, cushion and protect the deeper tissues, excrete wastes, regulate temperature and is the location of receptors for pain, sensation, pressu...

|- | Target || Sympathetic
Sympathetic nervous system

The Sympathetic Nervous System is a branch of the autonomic nervous system along with the enteric nervous system and parasympathetic nervous system....
 (muscarinic and adrenergic
Adrenergic

An adrenergic is a medication, or other substance, which has effects similar to, or the same as, epinephrine . Thus, they are a kind of sympathomimetic agents....
) || Parasympathetic (muscarinic) |- | sweat gland
Sweat gland

The skin contains two different groups of sweat glands: apocrine sweat glands and merocrine sweat glands. Both gland types contain myoepithelial cells , specialized epithelial cells located between the gland cells and the underlying basal lamina....
 secretions || M: stimulates (major contribution); a1: stimulates (minor contribution) || --- |- | erector pili || a1: stimulates || --- |}

See also

  • Reflex arc
    Reflex arc

    A reflex arc is the neural pathway that mediates a reflex action. In higher animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord....
  • Central pattern generator
    Central pattern generator

    "Central pattern generators can be defined as neural networks that can endogenously produce rhythmic patterned outputs" or as "neural circuits that generate periodic motor commands for rhythmic movements such as locomotion." CPGs have been shown to produce rhythmic outputs resembling normal "rhythmic motor pattern production" even in isola...
  • Neural top down control of physiology
    Neural top down control of physiology

    Neural top down control of physiology concerns the direct regulation by the brain of Human homeostasis . Cellular functions include the immune system production of T-lymphocytes and antibodies, and nonimmune related homeostasis functions such as liver gluconeogenesis, Renal sodium reabsorption, osmoregulation, and brown adipose tissue thermog...


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