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Anterior Pituitary Gland
The anterior pituitary (also called the adenohypophysis or pars anterior) is a major organ of the endocrine system. The anterior pituitary is the glandular, anterior lobe that together with the posterior pituitary (or neurohypophysis) makes up the pituitary gland (hypophysis) which, in humans, is located at the base of the brain, protruding off the bottom of the hypothalamus. The anterior pituitary regulates several physiological processes, including stress, growth, reproduction, and lactation. Proper functioning of the anterior pituitary and of the organs it regulates can often be ascertained via blood tests that measure hormone levels. Structure The pituitary gland sits in a protective bony enclosure called the sella turcica (''Turkish chair/saddle''). It is composed of three lobes: the anterior, intermediate, and posterior lobes. In many animals, these lobes are distinct. However, in humans, the intermediate lobe is but a few cell layers thick and indistinct; as a resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oral Mucosa
The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed '' lamina propria''. The oral cavity has sometimes been described as a mirror that reflects the health of the individual. Changes indicative of disease are seen as alterations in the oral mucosa lining the mouth, which can reveal systemic conditions, such as diabetes or vitamin deficiency, or the local effects of chronic tobacco or alcohol use. The oral mucosa tends to heal faster and with less scar formation compared to the skin. The underlying mechanism remains unknown, but research suggests that extracellular vesicles might be involved. Classification Oral mucosa can be divided into three main categories based on function and histology: * ''Lining mucosa'', nonkeratinized stratified squamous epithelium, found almost everywhere else in the oral cavity, including the: ** ''Alveolar mucosa'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hormone
A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physiology and behavior. Hormones are required for the normal development of animals, plants and fungi. Due to the broad definition of a hormone (as a signaling molecule that exerts its effects far from its site of production), numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. Estrogen, oestrogen and brassinosteroid), amino acid derivatives (e.g. epinephrine and auxin), protein or peptides (e.g. insulin and CLE peptides), and gases (e.g. ethylene and nitric oxide). Hormones are used to communicate between organ (anatomy), organs and Tissue (biology), tissues. In vertebrates, hormones are responsible for regulating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pineal Gland
The pineal gland (also known as the pineal body or epiphysis cerebri) is a small endocrine gland in the brain of most vertebrates. It produces melatonin, a serotonin-derived hormone, which modulates sleep, sleep patterns following the diurnal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two cerebral hemisphere, hemispheres, tucked in a groove where the two halves of the thalamus join. It is one of the neuroendocrinology, neuroendocrine Circumventricular organs, secretory circumventricular organs in which capillaries are mostly Vascular permeability, permeable to solutes in the blood. The pineal gland is present in almost all vertebrates, but is absent in Protochordata, protochordates in which there is a simple pineal homologue. The hagfish, archaic vertebrates, lack a pineal gland. In some species of amphibians and reptiles, the gland is linked to a light-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melatonin
Melatonin, an indoleamine, is a natural compound produced by various organisms, including bacteria and eukaryotes. Its discovery in 1958 by Aaron B. Lerner and colleagues stemmed from the isolation of a substance from the pineal gland of cows that could induce skin lightening in common frogs. This compound was later identified as a hormone secreted in the brain during the night, playing a crucial role in regulating the sleep-wake cycle, also known as the circadian rhythm, in vertebrates. In vertebrates, melatonin's functions extend to Entrainment (chronobiology), synchronizing sleep-wake cycles, encompassing sleep-wake timing and blood pressure regulation, as well as controlling seasonal rhythmicity (circannual cycle), which includes reproduction, fattening, molting, and hibernation. Its effects are mediated through the activation of melatonin receptors and its role as an antioxidant. In plants and bacteria, melatonin primarily serves as a defense mechanism against oxidative ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoperiod
Photoperiod is the change of day length around the seasons. The rotation of the earth around its axis produces 24 hour changes in light (day) and dark (night) cycles on earth. The length of the light and dark in each phase varies across the seasons due to the tilt of the earth around its axis. The photoperiod defines the length of the light, for example a summer day the length of light could be 16 hours while the dark is 8 hours, whereas a winter day the length of day could be 8 hours, whereas the dark is 16 hours. Importantly, the seasons are different in the northern hemisphere than the southern hemisphere. Photoperiodism is the physiological reaction of organisms to the length of light or a dark period. It occurs in plants and animals. Plant photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light and dark periods. They are classified under three groups according to the photoperiods: short-day plants, long-day plants, and day ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TSHB
Thyroid stimulating hormone, beta also known as TSHB is a protein which in humans is encoded by the ''TSHB'' gene. Function Thyrotropin-stimulating hormone (TSH) is a noncovalently linked glycoprotein heterodimer and is part of a family of pituitary hormones containing a common alpha subunit ( TSHA) and a unique beta subunit (this protein) that confers specificity. See also * thyroid stimulating hormone The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans, it is a butterfly-shaped gland located in the neck below the Adam's apple. It consists of two connected lobes. The lower two thirds of the lobes are connected by ... References Further reading * * * * * * * * * * * * * * * * * * * * {{gene-1-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basophil Cell
An anterior pituitary basophil is a type of cell in the anterior pituitary which manufactures hormones. It is called a basophil because it is basophilic (readily takes up bases), and typically stains a relatively deep blue or purple. These basophils are further classified by the hormones they produce. (It is usually not possible to distinguish between these cell types using standard staining techniques.) *Produced only in pregnancy by the developing embryo. See also * Chromophobe cell :* Melanotroph * Chromophil :* Acidophil cell * Oxyphil cell * Oxyphil cell (parathyroid) * Pituitary gland * Neuroendocrine cell * Basophilic Basophilic is a technical term used by pathologists. It describes the appearance of cells, tissues and cellular structures as seen through the microscope after a histological section has been stained with a basic dye. The most common such dye ... References External links * {{Authority control Histology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acidophils
In the anterior pituitary, the term "acidophil" is used to describe two different types of cells which stain well with acidic dyes. * somatotrophs, which secrete growth hormone (a peptide hormone) * lactotrophs, which secrete prolactin (a peptide hormone) When using standard staining techniques, they cannot be distinguished from each other (though they can be distinguished from basophils and chromophobes), and are therefore identified simply as "acidophils". See also * Eosinophilic * Acidophile (histology) * Basophilic * Chromophobe cell :* Melanotroph * Chromophil :* Basophil cell * Oxyphil cell * Oxyphil cell (parathyroid) * Pituitary gland * Neuroendocrine cell Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules (hormones) into the blood. In this way they bri ... References {{Authority control Histology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromophil
A chromophil is a cell which is easily stainable by absorbing chromium salts used in histology to increase the visual contrast of samples for microscopy. Function Chromophil cells are mostly hormone-producing cells containing so-called chromaffin granules. In these subcellular structures, amino acid precursors to certain hormones are accumulated and subsequently decarboxylated to the corresponding amines, for example epinephrine, norepinephrine, dopamine or serotonin. Chromophil cells therefore belong to the group of APUD (amine precursor uptake and decarboxylation) cells. Location These cells are scattered throughout the whole body, but particularly in glands such as the hypothalamus, hypophysis, thyroid, parathyroid and pancreas. In adult animals, chromophil cells make up the largest portion of the stria in the cochlear duct. See also * Chromophobe cell * Melanotroph * Acidophil cell * Basophil cell * Oxyphil cell (pathology) * Oxyphil cell (parathyroid) * Pituitary glan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromophobe Cell
A chromophobe cell is a cell that does not stain readily, and thus appears relatively pale under the microscope. It is contrasted with a chromophil cell that does stain easily. Chromophobe cells are one of three cell stain types present in the anterior and intermediate lobes of the pituitary gland, the others being basophilic and acidophilic. One type of chromophobe cell is known as amphophilic. Amphophils are epithelial cells found in the anterior and intermediate lobes of the pituitary. Together, these epithelial cells are responsible for producing the hormones of the anterior pituitary and releasing them into the bloodstream. Melanotrophs (also, Melanotropes) are another type of chromophobe which secrete melanocyte-stimulating hormone (MSH). Clinical significance "Chromophobe" also refers to a type of renal cell carcinoma Renal cell carcinoma (RCC) is a kidney cancer that originates in the lining of the Proximal tubule, proximal convoluted tubule, a part of the very smal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pars Nervosa
The posterior pituitary (or neurohypophysis) is the posterior lobe of the pituitary gland which is part of the endocrine system. Unlike the anterior pituitary, the posterior pituitary is not glandular, but largely a collection of axonal projections from the hypothalamus that terminate behind the anterior pituitary, and serve as a site for the secretion of neurohypophysial hormones (oxytocin and vasopressin) directly into the blood. The hypothalamic–neurohypophyseal system is composed of the hypothalamus (the paraventricular nucleus and supraoptic nucleus), posterior pituitary, and these axonal projections. Structure The posterior pituitary consists mainly of neuronal projections (axons) of magnocellular neurosecretory cells extending from the supraoptic and paraventricular nuclei of the hypothalamus. These axons store and release neurohypophysial hormones oxytocin and vasopressin into the neurohypophyseal capillaries, from there they get into the systemic circulation (and pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
