China
Africa
Explore chapters and articles related to this topic
Kidney Structure and Physiology
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Joel M. Henderson and Mostafa Belghasem
Aldosterone, a steroid hormone secreted by the adrenal cortex, acts on the distal convoluted tubules causing increased sodium reabsorption and potassium secretion. As a result of increased sodium reabsorption, concomitant water reabsorption also occurs, resulting in increased blood volume and elevated blood pressure. Aldosterone acts by the activation of the Na-K ATPase pump on the basolateral membrane of the distal convoluted tubular epithelium, and by increasing the luminal membrane permeability to sodium. Aldosterone is released from the adrenal cortex in response to decreased plasma sodium and increased plasma potassium concentrations, through a direct eect on the adrenal cortex.
The relation between psychosocial working conditions and work-related musculoskeletal complaints
Published in Richard Graveling, Ergonomics and Musculoskeletal Disorders (MSDs) in the Workplace, 2018
Leif W. Rydstedt, J. Paul Weston
The HPA system utilises cortisol to influence a wide variety of body systems and has a predominantly anti-inflammatory effect (Kristenson et al., 2004). Stress activates the hypothalamus to release adrenocorticotropic hormone (ACTH), which chemically mediates the release of cortisol from the adrenal cortex.
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
The outer layer of the adrenal cortex, the zona glomerulosa, produces aldosterone, which is necessary for reabsorption of sodium in the kidney. An excess of aldosterone causes salt and water retention. The secretion of aldosterone is regulated by rennin, a hormone secreted by the kidney.
Effect of novel recovery garments utilising nanodiamond- and nanoplatinum-coated materials (DPV576-C) on physical and psychological stress in baseball players: A randomised, placebo-controlled trial
Published in European Journal of Sport Science, 2019
Youngju Choi, Mizuho Makita, Yuki Nakamura, Kousaku Yamamoto, Takaaki Nara, Takashi Kawamura, Hidehiro Fukuda, Hideki Katano, Shumpei Miyakawa, Seiji Maeda
The most frequently used method for assessing exercise-related stress is the determination of circulating levels of hormones, such as cortisol (Newcomer et al., 1999), which is known to have immunomodulatory effects (Steensberg, Fischer, Keller, Moller, & Pedersen, 2003). Therefore, we used cortisol levels as a marker of physical stress in the present study. Cortisol plays a central role in physiological and psychological responses to stress, with the activation of the hypothalamic–pituitary–adrenal axis stimulating its release from the adrenal cortex (McEwen, 2007). Lower cortisol concentrations may indicate greater resilience to stressful situations (Stansbury & Gunnar, 1994), and sleep quality affects cortisol responses (Bassett, Lupis, Gianferante, Rohleder, & Wokf, 2015). No significant change in the total PSQI score (i.e. sleep quality) was found in either the RG or the placebo group (RG group: mean 5.5, s x - = 0.4 to mean 5.5, s x - = 0.4; placebo group: mean 6.0, s x - = 0.5 to mean 6.0, s x - = 0.5, respectively; P > 0.05 for both), suggesting that sleep quality could not have affected the cortisol levels in this study. Therefore, the decreased cortisol level found in athletes wearing the DPV576-C garments overnight might have enhanced their recovery from the intensified training-induced stress.
Fluid and electrolyte balance considerations for female athletes
Published in European Journal of Sport Science, 2022
Paola Rodriguez-Giustiniani, Nidia Rodriguez-Sanchez, Stuart D.R. Galloway
Sodium and water filter freely from the renal glomerular capillaries and undergo considerable reabsorption (usually more than 99%). Most sodium and water reabsorption (about 2/3rds) occurs in the proximal tube, but the primary hormonal regulation of reabsorption occurs in the collecting ducts. Sodium reabsorption is an active process happening in all tubular segments except the descending limb of the loop of Henle, and water reabsorption occurs by diffusion and is dependent upon sodium reabsorption. The kidneys also balance potassium intake with potassium excretion and are primarily responsible for maintaining total body potassium content. The main determinant of permeability, and consequently of water reabsorption, in the collecting tubes is the action of AVP (Hew-Butler, 2010). When AVP plasma concentration is high, the water permeability of the collecting tubes is increased. Water reabsorption is maximal, and the final urine volume is minimal (<1% of the filtered water). Without the action of AVP, the water permeability of the collecting tubes is very low and very little water is reabsorbed, allowing a greater amount of water left in the tubule to be excreted in the urine. Cardiovascular baroreceptors mediate posterior pituitary secretion of AVP with a low extracellular volume stimulating AVP secretion, and a high extracellular volume inhibiting it (Figure 1). AVP is also affected by osmoreceptors in the hypothalamus with a high perfusing osmolality stimulating AVP secretion, and a low osmolality inhibiting it (Perrier et al., 2013; Schrier, Berl, & Anderson, 1979; Stockand, 2010; Thornton, 2010). The RAAS also plays a crucial role in body water volume regulation through actions on electrolyte balance. Plasma angiotensin II (ANG II) is elevated during salt depletion and reduced when the individual is sodium replete. Elevation of ANG II induces increased secretion of aldosterone from the adrenal cortex which subsequently stimulates sodium reabsorption by the renal cortical collecting ducts. During exercise, there is primarily a stimulus for the release of AVP caused by an increase in osmolality and a decrease in plasma volume (Hew-Butler, 2010; Sollanek, Staab, Kenefick, & Cheuvront, 2020) particularly in situations where fluid losses are high, such as with exercise and heat stress.