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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 posterior pituitary is composed mainly of nervous tissue descending from the hypothalamus and produces two hormones: The antidiuretic hormone (vasopressin);Oxytocic hormone (oxytocin). The antidiuretic hormone (ADH) is involved intimately with water balance as it controls or regulates the amount of water that is reabsorbed in the kidney. Large doses of ADH cause high blood pressure or hypertension since the hormone causes vasoconstriction or contraction (narrowing) of blood vessels. The amount of ADH secreted by the posterior pituitary is controlled by the amount of water in the blood. If the body is short of water, more ADH will be secreted, and more water will be reabsorbed by the kidney tubules and less urine will be formed.
Kidney Structure and Physiology
Published in Joseph D. Bronzino, Donald R. Peterson, Biomedical Engineering Fundamentals, 2019
Joel M. Henderson and Mostafa Belghasem
Antidiuretic hormone (ADH), also known as vasopressin, participates in the maintenance of body uid homeostasis. e principal action of ADH is to increase the renal collecting duct permeability to water. ADH is synthesized in the hypothalamus and is transferred to the posterior pituitary where it is stored to be released into the systemic circulation. e secretion of ADH occurs in response to hemodynamic signals, including plasma hyperosmolality (increased solute concentration), hypovolumia and hypotension, increased sympathetic activity, and by the direct eect of angiotensin II on the hypothalamus. However, the primary stimulus of ADH secretion is hyperosmolality. e hormone binds to its receptors, V2 receptors, located on the basal membrane of the collecting tubules, resulting in the insertion of aquaporin channels into the collecting duct epithelial cell membrane, increased water reabsorption, increased urine concentration, and decreased urine volume. ADH also causes arterial vasoconstriction, increasing the systemic blood pressure when released in large amounts.
Clinical Effects of Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
Control of renal excretion of water is vested mainly in the supraoptic nuclei. When the body fluids become too concentrated, the neurons of these areas become stimulated. Nerve fibers from these neurons project downward through the infundibulum of the hypothalamus into the posterior pituitary gland, where the nerve endings secrete the antidiuretic hormone—vasopressin. This hormone is then absorbed into the blood and transported to the kidneys, where it acts on the collecting ducts of the kidneys to cause increased reabsorption of water. This stimulation decreases loss of water into the urine but allows continuing excretion of electrolytes, thus decreasing the concentration of the body fluids back toward normal. Chemically sensitive patients often have problems with this apparatus causing a loss in homeostasis resulting in peripheral and periorbital edema because they have difficulty urinating or they may urinate too frequently.
Bringing human-animal interaction to sport: Potential impacts on athletic performance
Published in European Journal of Sport Science, 2022
Sutton Marvin, Kennet Sorenson, Jeffrey R. Stevens
While stress provides one biological pathway that is affected by interacting with animals, the oxytocin system is another, related pathway. Produced in the hypothalamus and released by the posterior pituitary, oxytocin is a peptide hormone that is a known antagonist of cortisol and other physiological mechanisms of stress (Uvnäs-Moberg, 1998), so increasing its concentration could lead to a decrease in stress. Oxytocin influences the autonomic nervous system and the immune system, providing anxiety-reducing, analgesic, anti-inflammatory, and antioxidant effects (Carter et al., 2020). Oxytocin has also been found to positively affect levels of social attention, empathy, trust, and relationship building (MacDonald & MacDonald, 2010).
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
Homeostasis to maintain a constant water and electrolyte balance involves the coordination of many inputs/outputs, including neural pathways and integrative centres in the brain and peripheral effectors (Zimmerman et al., 2016; Figure 1). Total body water (TBW) can be most simply subdivided into extra cellular fluid (ECF) and intra cellular fluid (ICF) compartments. ECF is composed of three major compartments: plasma, interstitial, and connective tissue water. The largest component is ICF which has been reported to be around 26 litres (59% of TBW) or 34% of total body mass in an average male and around 19 litres (61% of TBW) or 31% of total body mass in an average female (Ritz et al., 2008). At rest, a water deficit increases the ionic concentration of the extracellular fluid compartment (increased osmolality, decreased plasma volume) and this draws water from the intracellular compartment (Nose, Mack, Shi, & Nadel, 1988). Two receptors also sense this osmotic stimulus in the brain, one regulating drinking behaviour (thirst) and the other controlling renal function (Fitzsimons, 1998; Kanbay et al., 2019; Leib, Zimmerman, & Knight, 2016; Thornton, 2010). A fluid deficit will lead not only to a decrease in glomerular filtration rate and a subsequent renin-angiotensin-aldosterone system (RAAS) response to decrease sodium excretion but also will increase the release of arginine vasopressin (AVP) from the posterior pituitary to alter renal tubular water reabsorption (Stockand, 2010). These actions counter the reduced effective circulating volume and, when combined with the thirst response, drive increased fluid intake to restore body water balance. If there is an excess of water, the lower ionic concentration of body fluids (reduced osmolality, increased plasma volume) will result in the opposite actions. Thus, the kidneys play a central role in regulating inorganic ion composition and fluid volume in the internal environment.
Effects of whey protein in carbohydrate-electrolyte drinks on post-exercise rehydration
Published in European Journal of Sport Science, 2018
Liang Li, Feng-Hua Sun, Wendy Ya-Jun Huang, Stephen Heung-Sang Wong
An increase in plasma osmolality and a decrease in PV during exercise, along with significant BM loss, can trigger specific receptors in the adrenal cortex and posterior pituitary gland to promote the secretion of aldosterone and ADH (Kenefick et al., 2000; Stachenfeld et al., 1996). Aldosterone and ADH concentrations can be significantly increased with a dehydration level of 4% BM loss (Kenefick et al., 2000). In the current study, the aldosterone concentration increased from approximately 350 pg·mL−1 to 500 pg·mL−1 after the 60-min run. Previous studies have observed high aldosterone concentrations when participants consumed daily diets with relatively high protein contents because of the activated plasma renin activity after protein supplementation (Daniels & Hostetter, 1990; Lauridsen, Vase, Starklint, Bech, & Pedersen, 2010). A previous animal study reported that the concentrations of aldosterone and plasma sodium in rats was increased after the ingestion of milk protein solution or milk during post-exercise recovery, resulting in improved fluid retention (Ishihara et al., 2013). The CW-M and CW-H trials had higher aldosterone concentrations than the isocaloric CE-H trial at the end of recovery, which might enhance the reabsorption of sodium and water from the kidneys and improve fluid retention. However, the difference of aldosterone concentration was only observed at the end of recovery, indicating that this hormone may not have enough time to exert a significant effect on fluid balance, and further research is needed to clarify this issue. On the other hand, previous studies reported that protein ingestion also increases ADH levels (Daniels & Hostetter, 1990; Lauridsen et al., 2010). In the current study, the difference in ADH concentration was observed between the CW-H and CE-L trials after 1 h and 2 h of recovery, but no differences were observed among the CW-M, CW-H and CE-H isocaloric drinks. Therefore, it was difficult to clarify whether the energy density or whey protein affects ADH release in the current study, and the changes in ADH concentration were not the primary reason for the significant fluid retention after the ingestion of the CW-M or CW-H drink.