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Endocrinology (from endocrine + -ology) is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones.It is also concerned with the integration of developmental events proliferation, growth, and differentiation, and the psychological or behavioral activities of metabolism, growth and development, tissue function, sleep ...
According to the hypothesis, the high concentration of organic substances, particularly sugar, inside the phloem at a source such as a leaf creates a diffusion gradient (osmotic gradient) that draws water into the cells from the adjacent xylem. This creates turgor pressure, also called hydrostatic pressure, in the phloem. The hypothesis states ...
The hypothesis states that individuals with a heterozygous MHC would be capable of recognizing a wider range of pathogens and therefore of inciting a specific immune response against a greater number of pathogens—thus having an immunity advantage. Unfortunately, the MHC-heterozygote advantage hypothesis has not been adequately tested. [2]
Fluid mosaic model of a cell membrane. The fluid mosaic model explains various characteristics regarding the structure of functional cell membranes.According to this biological model, there is a lipid bilayer (two molecules thick layer consisting primarily of amphipathic phospholipids) in which protein molecules are embedded.
Hormones can be amino acid complexes, steroids, eicosanoids, leukotrienes, or prostaglandins. [3] The endocrine system is contrasted both to exocrine glands, which secrete hormones to the outside of the body, and to the system known as paracrine signalling between cells over a relatively short distance.
The aromatic/arginine or "ar/R" selectivity filter is a cluster of amino acids that help bind to water molecules and exclude other molecules that may try to enter the pore. It is the mechanism by which the aquaporin is able to selectively bind water molecules and so to allow them through, and to prevent other molecules from entering.
The two factors work together to return the plasma osmolality to its normal levels. ADH binds to principal cells in the collecting duct that translocate aquaporins to the membrane, allowing water to leave the normally impermeable membrane and be reabsorbed into the body by the vasa recta, thus increasing the plasma volume of the body.
To release active hormones quickly into the circulation, hormone biosynthetic cells may produce and store biologically inactive hormones in the form of pre-or prohormones. These can then be quickly converted into their active hormone form in response to a particular stimulus. [34] Eicosanoids are considered to act as local hormones. They are ...