Stress and Coping
Deborah Fish Ragin in Health Psychology, 2017
The adrenal glands consist of two components: the adrenal medulla and the adrenal cortex. The adrenal medulla is found in the inner layer of the adrenal glands. When stimulated by the sympathetic nervous system, the adrenal medulla produces catecholamine, a class of chemicals that contains epinephrine, norepinephrine, and cortisol (Segerstrom & Miller, 2004). You may be familiar with another name for epinephrine: adrenaline. If this is familiar, then you know that epinephrine (or adrenaline) helps boost the body’s energy level. Thus, when epinephrine is released in the body, the sympathetic system is activating the body in response to a stimulant, possibly a stress-provoking event. In fact, epinephrine is linked so closely with stress that it is sometimes used in studies as a physiological index of stress. When the sympathetic nervous system and adrenal glands interact to cause a reaction, we refer to the combined systems as the sympathetic-adrenal-medullary system (SAM).
Radionuclide scanning in the diagnosis and treatment of endocrine disorders
Philip E. Harris, Pierre-Marc G. Bouloux in Endocrinology in Clinical Practice, 2014
The adrenal medulla produces catecholamines (adrenaline and noradrenaline). The commonest tumor in the medulla is pheochromocytoma that arises from the paraganglion cells anywhere in the autonomic nervous system. Ninety percent of pheochromocytomas are sporadic; the remaining 10% are associated with neuroectodermal disorders such as neurofibromatosis, tuberous sclerosis, von Hippel–Lindau syndrome, or multiple endocrine neoplastic syndrome. On 123I- or 131I-MIBG scintigraphy, pheochromocytomas are depicted as an abnormal focal area of increased activity. This technique is especially useful for the detection of ectopic pheochromocytomas and also for detection of metastatic or locally recurrent disease because unlike ultrasound, CT, or MRI, it is inherently a whole-body imaging technique. Refer to the section “Neural crest tumors” for further details.
Endocrine System
Charles Paul Lambert in Physiology and Nutrition for Amateur Wrestling, 2020
The adrenal gland has two important areas from which it secretes hormones. One is the adrenal medulla and the other is the adrenal cortex. Both the adrenal medulla and the adrenal cortex are involved in the “fight or flight” response. The adrenal medulla secretes epinephrine (adrenaline) and norepinephrine (noradrenaline) while the adrenal cortex secretes the glucocorticoid cortisol and the mineralocorticoids, primarily aldosterone. Epinephrine has a myriad of effects, like stimulating the breakdown of glycogen in muscle and liver cells, increasing the strength of contraction of the heart, and liberating fatty acids and glycerol from triglycerides at the adipocyte. Also, epinephrine acts to cause dilation of the precapillary sphincters of the arterioles in skeletal muscle capillary beds allowing for increased perfusion, i.e., blood flow to skeletal muscle during exercise. Norepinephrine generally increases heart rate and causes vasoconstriction all over the body. As opposed to the hormonal control of the release of epinephrine and norepinephrine from the adrenal medulla it is under direct sympathetic nervous system control. That is, when “fight or flight” situation arises, the nervous system stimulates the release of epinephrine and norepinephrine from the adrenal medulla.
Adrenocortical carcinoma arising from the colonic mesentery
Published in Baylor University Medical Center Proceedings, 2022
Samuel Z. See, Sinan Ali Bana, Nuvaira Ather, Amy Haberman
Primary ACC is a malignant tumor arising from the adrenal gland, specifically the adrenal cortex. The two primary components of the adrenal gland, the adrenal cortex and adrenal medulla, are formed by separate embryologic origins. The cortex is derived from the urogenital ridge and celomic epithelium, while the medulla is derived from neural crest cells.2,3 The urogenital ridge is a structure within the embryologic mesoderm that also gives rise to the gonads, kidneys, and reproductive tract while the celomic epithelium produces the lining of the abdominal organs and surface of the body wall.3,4 This embryologic phenomenon is thought to explain the observation of ectopic adrenocortical tissue. However, these cases are rarely observed in adults because ectopic adrenal tissue typically atrophies during infancy.4 Reported sites of ectopy include the testes, ovaries, kidneys, bowel, pancreas, liver, lungs, and mesentery.1 To our knowledge, fewer than five cases of ectopic ACCs have been reported to arise from the mesentery, which was the case in our patient.5–7
Pheochromocytoma and sinus node dysfunction
Published in Baylor University Medical Center Proceedings, 2019
Mary Lee, Dane Langsjeon, Srikala Devabhaktuni, Greg Olsovsky
Pheochromocytoma is a rare neuroendocrine tumor reported in 0.2% of hypertensive patients.1 Symptoms result from the release of various catecholamines. The adrenal medulla predominantly releases epinephrine. However, most pheochromocytomas predominantly release norepinephrine, which stimulates alpha-1 and beta-1 receptors and results in vasoconstriction and positive chronotropic, dromotropic, and inotropic effects. Although commonly associated with hypertension and tachyarrhythmia, ectopic atrial and ventricular beats, episodic nodal rhythms, and abrupt changes in sinus interval have been reported during norepinephrine infusions.9 Proposed mechanisms include increased vagal discharge by the baroreceptor reflex in response to sudden increasing atrial pressure and subsequent adrenergic receptor desensitization leading to bradycardia, but this is more often seen in patients with elevated epinephrine vs norepinephrine levels.5,8
Cardiovascular and metabolic consequences of the association between chronic stress and high-fat diet in rats
Published in Stress, 2018
Bruna B. Simas, Everson A. Nunes, Carlos C. Crestani, Guilherme F. Speretta
Interestingly, while the food and energy intake was similar among control and CVS rats fed with SD, the rats exposed to CVS and fed with SD decreased body weight gain. The increased sympathetic nervous system activity and hypertrophied adrenals found in these rats may be involved in this response. For instance, the sympathetic nervous system directly targets peripheral organs and stimulate the adrenal medulla to increase circulating catecholamines, so allowing an immediate “fight-or-flight” response to the threat. Besides, the increase in circulating concentrations of corticosterone modifies tissue metabolism to inhibit energy storage and increases glucose availability to muscle and brain (Harris, 2015). Moreover, brown adipose tissue thermogenesis seems to be activated by CRF and the sympathetic nervous system (Harris, 2015), which could also increase energy expenditure. Indeed, a recent study demonstrated increased interscapular brown adipose tissue accumulation, increased energy expenditure and lipid oxidation, and lower body weight in a mouse model of chronic psychosocial defeat, even with high food intake (Coccurello et al., 2017).
Related Knowledge Centers
- Adrenal Cortex
- Adrenaline
- Autonomic Nervous System
- Chromaffin Cell
- Sympathetic Nervous System
- Catecholamine
- Norepinephrine
- Dopamine
- Ganglion
- Adrenal Gland