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Companion Animals Models of Human Disease
Published in Rebecca A. Krimins, Learning from Disease in Pets, 2020
The prevalence of GH (growth hormone)-secreting pituitary tumors in domestic cats (Felis catus) is ten-fold greater than in humans. The predominant inhibitory receptors of GH-secreting pituitary tumors are somatostatin receptors (SSTRs) and D2 dopamine receptors (DRD2). The expression of these receptors is associated with the response to somatostatin analog and dopamine agonist treatment in human patients with acromegaly. A study in cats evaluated pathological features of pituitaries from domestic cats with acromegaly, pituitary receptor expression, and investigated correlates with clinical data, including pituitary volume, time since diagnosis of diabetes, insulin requirement, and serum IGF1 concentration. Loss of reticulin structure was identified in 15 of 21 pituitaries, of which 10 of 15 exhibited acinar hyperplasia. SSTR1, SSTR2, SSTR5, and DRD2 mRNA were identified in the feline pituitary, whereas SSTR3 and SSTR4 were not. Expression of SSTR1, SSTR2, and SSTR5 was greater in acromegalic cats compared with controls. A negative correlation was identified between DRD2 mRNA expression and pituitary volume(24,25).
Saliva, Swallowing, and Lower Oesophageal Sphincter
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The three major paired salivary glands (parotid, sublingual and submandibular) and numerous small glands in the mucosa of the oral cavity secrete saliva into the mouth. Each salivary gland consists of acini that open into intercalated and striated ducts that empty into the excretory ducts. There are three types of acini: serous, mucous (which produce mucin) and mixed. The parotid gland is entirely serous, and the sublingual and the small glands are entirely mucus secreting. The submandibular gland, although mixed in nature, is predominantly serous.
The salivary glands
Published in Neeraj Sethi, R. James A. England, Neil de Zoysa, Head, Neck and Thyroid Surgery, 2020
The basic unit of a salivary gland consists of an acinus, a secretory duct and a collecting duct. The acinus has a central lumen surrounded by pyramidal-shaped cells and myoepithelial cells. It produces the primary secretion. Acini are classified as serous (numerous cytoplasmic granules), mucous (clear cytoplasm) or mixed.The secretory ducts are composed of intercalated and striated ducts, which are intralobular. They make saliva hypotonic by taking in Na+, releasing K+ and excreting HCO3−.The collecting ducts are composed of two cell layers – the inner flat cells and the outer columnar cells. When the myoepithelial cells contract, preformed secretions are expelled through the duct [3].
The efficacy of Origanum majorana nanocubosomal systems in ameliorating submandibular salivary gland alterations in streptozotocin-induced diabetic rats
Published in Drug Delivery, 2022
Dina B. E. Farag, Carol Yousry, Abdulaziz Mohsen Al-Mahallawi, Hesham I. El-Askary, Meselhy R. Meselhy, Nermeen AbuBakr
H&E-stained submandibular salivary gland sections of the diabetic untreated rats (group I) revealed severely distorted architecture. The glandular acini demonstrated loss of regular acinar configuration. Acinar blurred boundaries, loss of acinar cell septum, as well as massive cytoplasmic vacuolization were clearly demonstrated in most of the acini. Degenerative areas were evident in the granular convoluted tubules (GCTs) with obvious loss in cytoplasmic content as well as ductal cell vacuolization. The striated ducts showed indistinctly cellular basal boundaries with loss of basal striations (Figure 4(A)). Thinning and deformation of the epithelial lining of the excretory duct with loss of pseudo stratification were detected. The cell nuclei were flattened and apically displaced. Dissociated periductal connective tissue, as well as dilated congested ruptured blood vessel, was also observed (Figure 5(A)).
Lacrimal Gland Insufficiency in Aqueous Deficiency Dry Eye Disease: Recent Advances in Pathogenesis, Diagnosis, and Treatment
Published in Seminars in Ophthalmology, 2022
In chronic cicatrising conjunctivitis such as SJS, MMP, and chemical burns, there is an ongoing sub-conjunctival fibrosis, leading to the destruction of the lacrimal ductules, both in the palpebral and orbital lobes, which on histological examination is seen as peri-ductular, interlobar and interlobular lymphocytic infiltration and fibrosis. The acini, particularly in the orbital lobe, may remain uninvolved and retain their secretory property.44,45 These changes are in stark contrast to the diffuse glandular atrophy and inflammatory aggregation that is seen in SS. However, despite the relative preservation of acinar structure on histopathology, significant ultrastructural changes have also been observed, showing disturbance in productivity and secretory activity of the glands in cicatrising disease like SJS.46
Bioidentical hormones
Published in Climacteric, 2021
F. Z. Stanczyk, H. Matharu, S. A. Winer
Saliva is a complex fluid which is mostly produced by the parotid, submandibular, and sublingual salivary glands, with a small contribution from the buccal glands that line the mouth13. In addition, saliva contains variable amounts of gingival crevicular fluid, which leaks from the tooth–gum margin, or blood from oral abrasions or lesions. Steroid hormones can enter saliva by a variety of mechanisms but for most steroids the most common route is rapid passive diffusion through the acinar cells, which drain into the salivary ducts13. The acini are surrounded by blood capillaries that enable the passage of substances from the circulation into the salivary glands. In passive diffusion, lipid-soluble substances such as progesterone and E2 cross the cell membranes of capillaries and acini rapidly. It is only the non-protein-bound steroids that enter the acini; steroids bound to sex hormone-binding globulin (SHBG), corticosteroid-binding globulin (CBG) and albumin are too large to enter acinar cells.