Basic medicine: physiology
Roy Palmer, Diana Wetherill in Medicine for Lawyers, 2020
There are two main sorts of gland in the body. Exocrine glands, such as the salivary and sweat glands, secrete their juice into a duct, whereas endocrine or ductless glands secrete hormones directly into the bloodstream. Hormones are proteins that act as chemical messengers, travelling in the blood to modulate the activity of a target organ that possesses the relevant hormone receptor. Endocrine tissue is found in many different organs, but it is concentrated in certain glands of which the pituitary is the most important. The pituitary gland is located inside the skull just below the brain and contains two main lobes. The anterior lobe secretes tropic hormones that control the activity of several other glands, including the thyroid, adrenal, breast, ovary and testis; it also secretes growth hormone, which affects the growth of many organs. The posterior pituitary secretes vasopressin and oxytocin, which act on the kidney and uterus, respectively. Pituitary insufficiency therefore has widespread effects. Pituitary secretion is controlled by a feedback system: rising blood levels of hormones secreted by the target organ in response to the pituitary hormone inhibit the secretion of that tropic hormone.
Interstitial Lung disease In Childhood Rheumatic Disorders
Lourdes R. Laraya-Cuasay, Walter T. Hughes in Interstitial Lung Diseases in Children, 2019
Sjögren’s syndrome (SS) is an autoimmune disorder characterized by lymphocyte mediated destruction of the exocrine glands. Decreased secretions and mucosal dryness result. Involvement of the lacrimal and salivary glands leads to the well recognized syndrome of keratoconjunctivitis sicca and xerostomia. Exocrine glands in the gastrointestinal tract, skin, vagina, and respiratory tract may also be affected. The disease may occur alone (primary) or with another autoimmune rheumatic disease (secondary). The true prevalence of the disease is difficult to ascertain but it is more common in adults than any other autoimmune rheumatic disease except rheumatoid arthritis. Women are more commonly affected than men.35 The disease is known to occur in children. Athreya and associates36 have described in detail two young girls with SS and SLE. They also reviewed several reported series of patients with SS including other children with SS and SLE, and SS with RA. There were no pulmonary abnormalities described in these children.
Inhibitory Regulation of Gastrointestinal Organ Growth
Jean Morisset, Travis E. Solomon in Growth of the Gastrointestinal Tract: Gastrointestinal Hormones and Growth Factors, 2017
In anterior pituitary cells and pancreatic islets,99 peculiar vesicles appear to translocate somatostatin receptor from the cell interior to the plasma membrane; in these vesicles, receptors have a cytoplasmic orientation as visualized from gold-conjugated somatostatin binding to these vesicles.99 In islet cells,100 since glucose stimulates insulin release, it would concomitantly initiate translocation of somatostatin receptors from the cytosol to the plasma membrane. Such a process would sensitize insulin-B cells to somatostatin and provide a specific anatomical locus for somatostatin to inhibit hormone release integrated to the exocytosis process at the point of fusion of the secretion vesicle with the surface membrane. In pituitary cells,101 somatostatin inhibits fusion of calmodulin-stimulated secretion vesicles with the plasma membranes. This mechanism has been described only in secretion vesicles involved in hormone secretion and its existence in the exocytosis process of exocrine glands remains to be established.
The discovery of the lymphatic system in the seventeenth century. Part V: an ode to the nerves
Published in Acta Chirurgica Belgica, 2019
Raphael Suy, Sarah Thomis, Inge Fourneau
Excretory glands (now known as exocrine glands) were described by Wharton as being composed of very many pieces, connected to each other in a particular manner, and joined together by means of membranes and vessels [6]. These glands, such as the pancreas, the mandibular gland, the breasts in women, and a few others were supposed to ‘take some of the excess fluids of the passing nerves […] to put it down through their own vessels’ [6]. According to Wharton, formation of milk was more complex since milk was considered to be a mixture of chyle and vital fluid; the chyle was not passed directly from the intestines to the breast, but conveyed through the chyle-bearing duct into the left subclavian vein, thence to circulate through the ventricles of the heart to the arteries of the thorax where it was separated from the sanguineous parts of the blood to be stored in the ducts of the breast for feeding the child. However, children needed also ‘the noblest nutritious juice’ for the growth of their spermatic tissues. This specific matter was supplied by means of the thoracic nerves which were, according to Wharton, indeed much larger and more succulent at the time of giving milk [6].
Neuropsychiatric manifestations in primary Sjogren syndrome
Published in Expert Review of Clinical Immunology, 2022
Simone Appenzeller, Samuel de Oliveira Andrade, Mariana Freschi Bombini, Samara Rosa Sepresse, Fabiano Reis, Marcondes C. França
Sjogren’s syndrome (SS) is a complex autoimmune rheumatic disease characterized by chronic inflammation of the exocrine glands and the presence of autoantibodies against the ribonucleoprotein particles SSA/Ro and SSB/La [1,2]. Primary (p) SS refers to the diagnosis of SS in the absence of additional autoimmune disease [3]. The T cell mediated inflammation targets primary lacrimal and salivary glands [1]. Mononuclear cell infiltration and progressive injury of the exocrine glands are the main pathological features, and sicca syndrome is the clinical hallmark of the disease [3]. However, a wide spectrum of clinical manifestations have been described, varying from mild disease limited to exocrine glands to severe multi-systemic involvement, including but not limited to lungs, skin, kidney, and the nervous system [1,4]
Cardamonin inhibits pro-inflammatory cytokine production and suppresses NO pathway in PBMCs from patients with primary Sjögren’s syndrome
Published in Immunopharmacology and Immunotoxicology, 2018
Sarah Benchabane, Houda Belguendouz, Nassima Behairi, Amina Arroul-Lammali, Abdelhalim Boudjelida, Pierre Youinou, Chafia Touil-boukoffa
Sjögren’s syndrome (SS), is a systemic autoimmune disorder that primarily affects the exocrine glands (primary SS [pSS]), and less often affects connective tissues, known as secondary SS (sSS). This syndrome is characterized by immune cell infiltration of the salivary and/or lachrymal glands, leading to exocrine gland dysfunction, tissue destruction and chronic dysfunction1. The clinical manifestations of SS are broad, as patients may present with variable combinations of systemic extra-glandular manifestations, such as peripheral neuropathy, arthralgia, lung disease, among others. As is common in many autoimmune diseases, primary SS is a complex condition. In an attempt to tease out the factors at play, several untested hypotheses have been proposed to better understand the pathophysiology of pSS2. Indeed, the interplay between genetic, environmental and hormonal factors all play a role in triggering autoimmune responses, B- and T-cell hyperactivity, autoantibody production and progressive destruction of target organs3,4. Increased secretion of multiple pro-inflammatory cytokines and pro-inflammatory mediators, including the short-lived free radical nitric oxide (NO) generated by activated inducible nitric oxide synthase (iNOS), initiate and/or perpetuate the autoimmune lesions5–7. Expression of iNOS is transcriptionally regulated, particularly by nuclear factor-κB (NF-κB) activation8–10. NF-κB is a key element of the intracellular pro-inflammatory signaling cascades that control the expression of inflammation-related genes11.
Related Knowledge Centers
- Ceruminous Gland
- Epithelium
- Lacrimal Gland
- Mammary Gland
- Sweat Gland
- Gland
- Duct
- Salivary Gland
- Sebaceous Gland
- Prostate