Adrenal medulla
Medulla labeled at bottom right.
Gray's	subject #277 1280
Artery	superior suprarenal artery, middle suprarenal artery, Inferior suprarenal artery
Vein	suprarenal veins
Nerve	celiac plexus, renal plexus
Lymph	lumbar glands
Precursor	Neural crest

Medullary part of the adrenal gland (on the pointer). Gray's Anatomy the Respiratory apparatus ( Apparatus Respiratorius Respiratory system Respiratory apparatus Arteries are Blood vessels that carry blood away from the Heart. Each (left and right superior suprarenal artery is a branch of the Inferior phrenic artery on that side of the body The middle suprarenal arteries (middle capsular arteries suprarenal arteries are two small vessels which arise one from either side of the Abdominal aorta, opposite the Each Renal artery gives off some small inferior suprarenal branches to the Suprarenal gland, the Ureter, and the surrounding cellular tissue and muscles In the Circulatory system, a vein is a Blood vessel that carries Blood back toward the Heart (as opposed to Artery, a blood vessel The Suprarenal veins are two in number the right ends in the Inferior vena cava. A nerve is an enclosed cable-like bundle of peripheral Axons (the long slender projections of Neurons. The celiac plexus (also known as the solar plexus) is a complex network of nerves (a Plexus) located in the abdomen The renal plexus is formed by filaments from the Celiac plexus, the Aorticorenal ganglion, and the Aortic plexus. The lymphatic system in Vertebrates is a network of conduits that carry a clear fluid called Lymph. The lumbar lymph nodes (paraaortic nodes are a group of Lymph nodes residing in the Lumbar region Embryology (from Greek grc ἔμβρυον embryon, "unborn embryo" and grc -λογία -logia) is the study of the development The neural crest, a transient component of the Ectoderm, is located in between the Neural tube and the epidermis (or the free margins of the Neural folds

The adrenal medulla is part of the adrenal gland. In Mammals the adrenal glands (also known as suprarenal glands) are the triangle-shaped Endocrine glands that sit on top of the Kidneys their It is located at the center of the gland, being surrounded by the adrenal cortex. Situated along the perimeter of the Adrenal gland, the adrenal cortex mediates the stress response through the production of Mineralocorticoids and Glucocorticoids

Function

Composed mainly of hormone-producing chromaffin cells, the adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines adrenaline (epinephrine), noradrenaline (norepinephrine), and dopamine. Chromaffin cells are Neuroendocrine cells found in the medulla of the Adrenal gland (suprarenal gland - located above the kidneys and in other ganglia In Chemistry, an amino acid is a Molecule containing both Amine and Carboxyl Functional groups In Biochemistry, this Tyrosine (abbreviated as Tyr or Y) or 4-hydroxyphenylalanine, is one of the 20 Amino acids that are used by cells to synthesize Norepinephrine ( INN) (abbreviated norepi or NE) or noradrenaline ( BAN) (abbreviated NA or NAd) is a Dopamine is a Hormone and Neurotransmitter occurring in a wide variety of animals including both vertebrates and invertebrates

In response to stressors such as exercise or imminent danger, medullary cells release catecholamines into the blood in an 17:3 ratio of adrenaline to noradrenaline. In chemistry a stressor is something that either speeds up a Reaction rate or keeps the reaction rate the same Norepinephrine ( INN) (abbreviated norepi or NE) or noradrenaline ( BAN) (abbreviated NA or NAd) is a ^[1]

Notable effects of adrenaline and noradrenaline include increased heart rate and blood pressure, blood vessel constriction, bronchiole dilation, and increased metabolism, all of which are characteristic of the fight-or-flight response. Norepinephrine ( INN) (abbreviated norepi or NE) or noradrenaline ( BAN) (abbreviated NA or NAd) is a Measuring heart rate The Pulse rate (which in most people is identical to the heart rate can be measured at any point on the body where an Artery 's pulsation Blood pressure is also the title of a short story by Damon Runyan in Guys and Dolls and Other Stories Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels particularly the large Arteries, Arterioles The bronchioles or bronchioli are the first Airway branches that no longer contain Cartilage. Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. The fight-or-flight response', also called the fright, fight or flight response, hyperarousal or the acute stress response, was first Release of catecholamines is stimulated by nerve impulses, and receptors for catecholamines are widely distributed throughout the body.

Origin

Medullary cells are derived from the embryonic neural crest and, as such, are simply modified neurons. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular The neural crest, a transient component of the Ectoderm, is located in between the Neural tube and the epidermis (or the free margins of the Neural folds Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information

In particular, they are modified postganglionic cells of the sympathetic nervous system that have lost their axons and dendrites, receiving innervation from corresponding preganglionic fibers. In the Autonomic nervous system, fibers from the Ganglion to the effector organ are called postganglionic fibers. The Sympathetic Nervous System ( SNS) is a branch of the Autonomic nervous system along with the Enteric nervous system and Parasympathetic nervous An axon or nerve fiber is a long slender projectionof a nerve cell or Neuron, that conducts electrical impulses away from the neuron's Cell Dendrites (from Greek δένδρον déndron, “tree” are the branched projections of a Neuron that act to conduct the electrochemical In the Autonomic nervous system, fibers from the CNS to the ganglion are known as preganglionic fibers.

Moreover, as the synapses between pre- and postganglionic fibers are called ganglia, the adrenal medulla is actually a ganglion of the sympathetic nervous system. Autonomic ganglia are clusters of Neuronal cell bodies and their Dendrites and are essentially a junction between autonomic nerves originating from the Central

Pathology

Neoplasms including:

• Pheochromocytoma (most common) a catecholamine-secreting tumor of the adrenal medulla
• Neuroblastoma a neuroendocrine tumor of any neural crest tissue of the sympathetic nervous system
• Ganglioneuroma a tumor in the nerve cells of the peripheral nervous system

See also

• Adrenal gland

References

External links

• SUNY Labs 40:04-0202 - "Posterior Abdominal Wall: Blood Supply to the Suprarenal Glands"
• Anatomy Atlases - Microscopic Anatomy, plate 15.292 - "Adrenal Gland"
• Location of Adrenal medulla