Adrenal medulla

medullamedullary(medulla)adrenal medullarymedullar
The adrenal medulla (medulla glandulae suprarenalis) is part of the adrenal gland.wikipedia
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Adrenal gland

adrenal glandsadrenalsuprarenal gland
The adrenal medulla (medulla glandulae suprarenalis) is part of the adrenal gland.
Each gland has an outer cortex which produces steroid hormones and an inner medulla.

Chromaffin cell

chromaffin cellschromaffinchromaffin granules
Chromaffin cells are derived from the embryonic neural crest and, as such, are simply modified neurons.
Chromaffin cells, also pheochromocytes, are neuroendocrine cells found mostly in the medulla of the adrenal glands in mammals.

Adrenaline

epinephrineadrenaline junkieadrenalin
It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons.
The adrenal medulla is a minor contributor to total circulating catecholamines ( L -DOPA is at a higher concentration in the plasma), though it contributes over 90% of circulating adrenaline.

Dopamine

dopaminergic systemDAdopaminergic
It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons. The adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines; epinephrine, norepinephrine, and dopamine.
Dopamine is synthesized in a restricted set of cell types, mainly neurons and cells in the medulla of the adrenal glands.

Norepinephrine

noradrenalinenoradrenergicnoradrenalin
It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons.
Norepinephrine is synthesized from the amino acid tyrosine by a series of enzymatic steps in the adrenal medulla and postganglionic neurons of the sympathetic nervous system.

Sympathetic nervous system

sympatheticsympathetic nervesympathetic nerves
It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons.
This response is also known as sympatho-adrenal response of the body, as the preganglionic sympathetic fibers that end in the adrenal medulla (but also all other sympathetic fibers) secrete acetylcholine, which activates the great secretion of adrenaline (epinephrine) and to a lesser extent noradrenaline (norepinephrine) from it.

Catecholamine

catecholaminescatecholamine synthesiscatecholamine systems
The adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines; epinephrine, norepinephrine, and dopamine.
Release of the hormones epinephrine and norepinephrine from the adrenal medulla of the adrenal glands is part of the fight-or-flight response.

Fight-or-flight response

stress responsefight or flightfight-or-flight
Notable effects of adrenaline and noradrenaline include increased heart rate and blood pressure, blood vessel constriction in the skin and gastrointestinal tract, smooth muscle (bronchiole and capillary) dilation, and increased metabolism, all of which are characteristic of the fight-or-flight response.
More specifically, the adrenal medulla produces a hormonal cascade that results in the secretion of catecholamines, especially norepinephrine and epinephrine.

Heart rate

heartbeatresting heart ratemaximum heart rate
Notable effects of adrenaline and noradrenaline include increased heart rate and blood pressure, blood vessel constriction in the skin and gastrointestinal tract, smooth muscle (bronchiole and capillary) dilation, and increased metabolism, all of which are characteristic of the fight-or-flight response.
The catecholamines, epinephrine and norepinephrine, secreted by the adrenal medulla form one component of the extended fight-or-flight mechanism.

Neural crest

neural crest cellsneural crest cellcrest
Chromaffin cells are derived from the embryonic neural crest and, as such, are simply modified neurons.
The cells that stay in the sclerotome form the dorsal root ganglia, whereas those that continue more ventrally form the sympathetic ganglia, adrenal medulla, and the nerves surrounding the aorta.

Stressor

stressorsenvironmental and genetic stressorsenvironmental stresses
In response to stressors such as exercise or imminent danger, medullary cells release the catecholamines adrenaline and noradrenaline into the blood.
After which, the adrenal medulla secretes epinephrine.

Autonomic nervous system

autonomicautonomous nervous systemautonomic functions
In particular, they are modified postganglionic sympathetic neurons of the autonomic nervous system that have lost their axons and dendrites, receiving innervation from corresponding preganglionic fibers.

Absent adrenal gland

The adrenal medulla may be poorly formed or absent in cases of absent adrenal gland.
The adrenal medulla can be normally present, poorly formed, or absent, however even so the effects of circulatory catecholamine deficiency are generally mild (due to sympathetic nervous system compensation), except in episodes of hypoglycemia.

Adrenal cortex

adrenocorticalcortexadrenocortical cells
It is located at the center of the gland, being surrounded by the adrenal cortex.

Ganglion

gangliaganglion cellspreganglionic neurons
It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine in response to stimulation by sympathetic preganglionic neurons.

Embryo

embryosembryonalhuman embryos
Chromaffin cells are derived from the embryonic neural crest and, as such, are simply modified neurons.

Neuron

neuronsnerve cellsnerve cell
Chromaffin cells are derived from the embryonic neural crest and, as such, are simply modified neurons.

Axon

axonsnerve fiberaxonal
In particular, they are modified postganglionic sympathetic neurons of the autonomic nervous system that have lost their axons and dendrites, receiving innervation from corresponding preganglionic fibers.

Dendrite

dendritesdendriticdendritic arborization
In particular, they are modified postganglionic sympathetic neurons of the autonomic nervous system that have lost their axons and dendrites, receiving innervation from corresponding preganglionic fibers.

Preganglionic nerve fibers

preganglionicpreganglionic fiberspreganglionic fiber
In particular, they are modified postganglionic sympathetic neurons of the autonomic nervous system that have lost their axons and dendrites, receiving innervation from corresponding preganglionic fibers.

Autonomic ganglion

autonomic gangliaganglionautonomic
As a cluster of neuron cell bodies, the adrenal medulla is considered a ganglion of the sympathetic nervous system.

Hormone

hormoneshormonalprohormone
Rather than releasing a neurotransmitter, the cells of the adrenal medulla secrete hormones.

Amino acid

amino acidsresiduesresidue
The adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines; epinephrine, norepinephrine, and dopamine.

Tyrosine

Tyrtyrosine metabolismL-tyrosine
The adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines; epinephrine, norepinephrine, and dopamine.

Exercise

physical exerciseexercisingphysical activity
In response to stressors such as exercise or imminent danger, medullary cells release the catecholamines adrenaline and noradrenaline into the blood.