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).
Neuropeptides in the Regulation of Autonomic Function By the Dorsal Medulla
I. Robin A. Barraco in Nucleus of the Solitary Tract, 2019
The participation of the dorsal medulla oblongata in the regulation of autonomic function has been acknowledged for more than a century, but the pervasive influence of brainstem mechanisms in cardiovascular, respiratory, and gastric control has only been recognized recently. Information about the involvement of classical neurotransmitters in autonomic regulation is still incomplete, and the significance of neuropeptides in these mechanisms is just being uncovered. Although this chapter is focused on the role of neuropeptides in pathways of the dorsal medulla that subserve cardiovascular function, the contributions of peptides to respiratory and gastric mechanisms are also reviewed. Our recent observations of an interaction between angiotensin II (ANG II) and substance P (subP) in neuronal pathways of the dorsal medulla are presented as an example of the potential role of neuropeptides in cardiovascular regulation.
Hair Morphology, Biogenesis, Heterogeneity, Pathophysiology and Hair Follicle Penetration
Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters in Cosmetic Formulation, 2019
The hair shaft is composed of different layers. The inner layer of the hair is the medulla, which is surrounded by the cortex being responsible for the elasticity of the hair. The outer layer is represented by the cuticula, which consists of flat cornified cells that overlay one another and give the hair the typical roof tile-like structure (Buffoli et al., 2014). In humans, there are mainly two different hair types: the larger terminal hairs and the smaller vellus hairs. Terminal hairs are long and thick (>50 µm) and grow from a hair follicle that extends deeply into the subcutaneous fat tissue (>3000 µm). The vellus hairs are unpigmented, shorter than 2 cm, and thinner than 30 µm. The corresponding hair follicles extend only into the dermis (<1000 µm) (Meidan et al., 2005; Vogt et al., 2007).
The controlling role of nitric oxide within the shell of nucleus accumbens in the stress-induced metabolic disturbance
Published in Archives of Physiology and Biochemistry, 2021
Yasaman Husseini, Alireza Mohammadi, Gila Pirzad Jahromi, Gholamhossein Meftahi, Hedayat Sahraei, Boshra Hatef
The adrenal gland has two parts, medulla and core. The HPA axis terminates to the core, and sympathetic nerves stimulate the medulla part (Tsigos and Chrousos 2002). Previous studies have shown that, in chronic stress, the weight of the adrenal gland increased due to the increase in hyperplasia in the cerebrospinal region of the adrenal glands. This hyperplasia is due to the anterior pituitary hormone (ACTH) trophic effect on the activity of the adrenocortical fasiculatus cells, which can increase the volume and the number of these cells. Therefore, increase in the adrenal gland weight is one of the most important indicators of chronic stress (Bali and Jaggi 2015). Here, L-arginine at 1 μg/rat, that decreased the level of cortisol, increased the adrenal weight. It is proposed that VTA (Ventral tegmental area), which has a two-way communication with the NAc, is of two-way communications with locus coeruleus as the brain's noradrenaline source. The effects of locus coeruleus ultimately increase the modular activity of the adrenal gland (Mehendale et al.2004, Haghparast et al.2012, Ferrucci et al.2013). Our results showed that all doses of L-arginine increased the weight of the gland in stress conditions, especially 1 μg/rat, with probably further stimulation of the brain stem and following the increase in the adrenergic system activity in the medullary of adrenal gland. However, we did not find any scientific discussion to confirm above hypothesis and more experiences are needed to clarify the phenomena.
Takotsubo cardiomyopathy associated with Paragonimiasis westermani
Published in Paediatrics and International Child Health, 2018
Ryouhei Matsuoka, Jun Muneuchi, Yusaku Nagatomo, Daisuke Shimizu, Seigo Okada, Chiaki Iida, Hiromitsu Shirouzu, Mamie Watanabe, Yasuhiko Takahashi, Haruhiko Maruyama
Cerebral paragonimiasis including eosinophilic meningitis or encephalopathy accounted for about 20% of cases of paragonimiasis [3,13]. Typical MRI findings of cerebral paragonimiasis are conglomerates of multiple ring-shaped shadows or enhancements of so-called ‘soap bubble’ forms in one hemisphere, as seen in the present case [14]. The pathophysiology of cerebral paragonimiasis involves the migration of lung fluke to the brain and catabolism of brain tissue which is followed by an immunological reaction. The main pathological changes include invasive inflammation, cerebral haemorrhage or cerebral infarction [3]. Takotsubo cardiomyopathy is also triggered by central nervous system disorders such as stroke or intracranial bleeding [15,16]. In a recent study of Takotsubo cardiomyopathy complicating ischaemic stroke, ischaemic lesions in the right anterior cerebral arterial circulation, especially the insula cortices and peri-insular area, were found to be associated with Takotsubo cardiomyopathy [15]. It has been reported that the insula and medulla play an important role in cardiovascular autonomic function [17,18]. In this case, the MRI demonstrated evidence of cerebral paragonimiasis of the cortex and subcortical area of the right frontal lobe, which suggests that Takotsubo cardiomyopathy could be caused by central autonomic network dysfunction associated with cerebral lesions. It is also speculated that cardioembolic stroke could be caused by a left ventricular thrombus associated with Takotsubo cardiomyopathy or ventricular fibrillation.
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
Related Knowledge Centers
- Area Postrema
- Autonomic Nervous System
- Brainstem
- Cerebellum
- Vasomotor
- Vomiting
- Heart
- Neuron
- Sneeze
- Respiratory Center