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Cushing's syndrome
Published in Nadia Barghouthi, Jessica Perini, Endocrine Diseases in Pregnancy and the Postpartum Period, 2021
Corticotropin-releasing hormone (CRH) physiologyCRH is normally synthesized in the hypothalamus. The placenta also synthesizes and releases biologically active CRH. There is an exponential rise in CRH secretion from the placenta by 1000-fold beginning at 8 weeks gestation. This production peaks at 40 weeks, preceding onset of labor.5–7The CRH level later normalizes to nonpregnant levels within 24 hours of delivery. Placental CRH assists with development and maturation of the fetal HPA axis and fetal adrenal glands resulting in fetal adrenal steroidogenesis.4–7 The placental CRH acts on the maternal HPA axis as well and triggers increased maternal cortisol production.
Fever in the ICU
Published in Stephen M. Cohn, Alan Lisbon, Stephen Heard, 50 Landmark Papers, 2021
Juan M. Perez Velazquez, Sandeep Jubbal
The hypothalamus functions as the body temperature regulatory center. Fever results from the activity of endogenous pyrogens that intensifies prostaglandin E2 production in the preoptic region of the hypothalamus [2]. Individual differences in normal body temperature vary depending on several factors, including demographics, comorbid conditions, and physiology [3]. Although arbitrary, a body temperature of 38.3°C (101°F) or higher has been the generally accepted definition of fever. A lower temperature of 38°C (100.4°F) is considered a fever in the immunocompromised or neutropenic patient, as they may have a blunted inflammatory response preventing body temperature elevation [4].
The patient with acute neurological problems
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
The hypothalamus is beneath the thalamus and controls temperature, water metabolism, autonomic function, physical emotion and pituitary secretions such as growth hormone. The hypothalamus contains a feeding centre which contributes to the sense of hunger and a satiety centre that causes a sense of fullness and triggers individuals to stop eating. The thirst centre is also located within the hypothalamus. Osmoreceptors in the hypothalamus are stimulated by an increase in blood osmotic pressure, triggering the sensation of thirst. The hypothalamus influences the circadian rhythm of the body – the sleep/wake cycle.
When to investigate for secondary hyperhidrosis: data from a retrospective cohort of all causes of recurrent sweating
Published in Annals of Medicine, 2022
Nived Collercandy, Camille Thorey, Elisabeth Diot, Leslie Grammatico-Guillon, Eve Marie Thillard, Louis Bernard, François Maillot, Adrien Lemaignen
Thermoregulatory sweating is a physiological mechanism to maintain thermoregulation homoeostasis in humans. Sweating is triggered by a body temperature increase, which is sensed by peripheral and central thermoreceptors under the central control of the hypothalamus [1,2]. The hypothalamus, in turn, activates the autonomic nervous system through the efferent sympathetic pathway. Sweat is primarily produced by eccrine glands, which are widespread throughout the skin in significant numbers (1.6–4 million on the whole body) with variable density. These glands have muscarinic receptors that can be bound to acetylcholine, a neurotransmitter released from sudomotor nerves. Upon stimulation, human sweat glands can produce an average sweat rate of 1.4 l/h. This rate is regulated by body fluid volume and mechanically by skin hydration status [2].
Psychometric Properties of the Turkish version of the Morningness - Eveningness Stability Scale improved (MESSi) in Adolescents
Published in Chronobiology International, 2021
Hakan Öğütlü, Sabide Duygu Uygun, Christoph Randler
The circadian rhythm that regulates the sleep-wake cycle is affected by the suprachiasmatic nucleus of the hypothalamus, serving as the internal clock for organisms. External factors, especially daylight or photoperiod, temperature and season, further regulate the sleep-wake cycle and adapt it to the environment (Randler and Rahafar 2017). Social and societal influences include having irregular shift schedules, late/early school hours and social events, and exposure to environmental changes. Despite these influential factors, considerable individual differences in circadian patterns exist, and people exhibit different chronotypes like “morningness” or “eveningness,” due to the diversity in biological and behavioral rhythms, including the sleep-wake cycle, body temperature, and cortisol and melatonin secretion (Adan et al. 2010).
Renal and Hepatic Disease: Cnidoscolus aconitifolius as Diet Therapy Proposal for Prevention and Treatment
Published in Journal of the American College of Nutrition, 2021
Maria Lilibeth Manzanilla Valdez, Maira Rubi Segura Campos
Another important function of the kidneys is the regulation of the hydro-electrolytic balance, this is done by the excretion of water and electrolytes such as ions like chlorine (Cl−), potassium (K+), calcium (Ca+2), hydrogen (H+), magnesium (Mg+2), and phosphorus (PO4−3). The purpose of this system in the kidney is to maintain homeostasis in the body and to regulate the intake of water in the body. The regulation of water intake is related to plasma osmolality; the hypothalamus detects the changes of osmolality, which activates the sensation of thirst and the secretion of the antidiuretic hormone (ADH). In CKD, the reabsorption of sodium (Na+) increases, consequently the extracellular volume changes and urinary excretion diminishes, which results in edema (18). Edema is very common in CKD; therefore, it is necessary to have an accurate control of fluid intake. The WHO determined that the recommended daily intake (RDI) of Na+ for the adult population is 1600 mg per day. For its part, the study conducted in 2009 by the Mexican Institute of Medical Science and Nutrition Salvador Zubirán, estimated that the daily consumption of salt in Mexico is 9 g in men and 7 g in women, noticing that Mexicans have a high consumption of sodium, and how dangerous a diet with this characteristics is. Diets with a high Na+ content stimulate electrolyte imbalance in CKD (3).