- published: 10 Aug 2015
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The adrenal medulla (Latin: medulla glandulae suprarenalis) is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. 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 consists of irregularly shaped cells grouped around blood vessels. These cells are intimately connected with the sympathetic division of the autonomic nervous system (ANS). In fact, these adrenal medullary cells are modified postganglionic neurons, and preganglionic autonomic nerve fibers lead to them directly from the central nervous system. The adrenal medulla therefore affects available energy, heart rate, and metabolism.
Rather than releasing a neurotransmitter, the cells of the adrenal medulla secrete hormones.
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 epinephrine, norepinephrine, and dopamine.
The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which produces steroid hormones and an inner medulla. The adrenal cortex itself is divided into three zones: zona glomerulosa, the zona fasciculata and the zona reticularis.
The adrenal cortex produces three main types of steroid hormones: mineralocorticoids, glucocorticoids, and androgens. Mineralocorticoids (such as aldosterone) produced in the zona glomerulosa help in the regulation of blood pressure and electrolyte balance. The glucocorticoids cortisol and corticosterone are synthesized in the zona fasciculata; their functions include the regulation of metabolism and immune system suppression. The innermost layer of the cortex, the zona reticularis, produces androgens that are converted to fully functional sex hormones in the gonads and other target organs. The production of steroid hormones is called steroidogenesis, and involves a number of reactions and processes that take place in cortical cells. The medulla produces the catecholamines adrenaline and noradrenaline, which function to produce a rapid response throughout the body in stress situations.
http://www.handwrittentutorials.com - This tutorial explores the Adrenal Glands, their various microscopic layers and the steroid hormones and catecholamines they release. The control of the release of these hormones is also broadly addressed. For more entirely FREE tutorials and the accompanying PDFs visit http://www.handwrittentutorials.com
Part 5 in a 6 part lecture on the AUTONOMIC NERVOUS SYSTEM in a flipped Human Physiology course taught by Wendy Riggs. CC-BY. Watch the whole lecture (all 6 videos) by going to the PLAYLIST: http://www.youtube.com/playlist?list=PL5GRRRmaGVqWEyICMJOI04coQoR3_vvgh
Explanation for the adrenal medulla for our pathology class at the University of St. Augustine. The explanation is specific to the material we need to know for our pathology class. Thank you for your comments and for watching my video! This video belongs to Ashley Tacloban.
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Paul Andersen explains how epinephrine is responsible for changes in chemistry of our body associated with the fight or flight response. Epinephrine released by the adrenal medulla are received by a number of organs associated with the sympathetic nervous system.
The Adrenal Cortex and Medulla The adrenal glands sitting above the kidneys are richly supplied with blood and with sypathetic nerve endings. Block sections show the blood supply and cellular arrangement of the adrenals. Two different regions are distinguishable--the cortex, controlled by the pituitary hormone ACTH, produces hormones which maintain body chemistry, and the medulla, which secretes adrenaline and noradrenaline to increase body activity.