Morphogenesis. Morphogenesis (from the Greek morphê shape and genesis creation, literally, "beginning of the shape") is the biological process that causes an organism to develop its shape. It is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation. Morphogenetic responses may be induced in organisms by hormones, by environmental chemicals ranging from substances produced by other organisms to toxic chemicals or radionuclides released as pollutants, and other plants, or by mechanical stresses induced by spatial patterning of the cells.
History[edit] The term histomorphogenesis was coined by Ricqlès et al. (2001) for the same process in bone histology.[4] Molecular basis[edit] Cellular basis[edit] Morphogenesis arises because of changes in the cellular structure or how cells interact in tissues.[6] These changes can result in tissue elongation, thinning, folding or separation of one tissue into distinct layers. Cell-cell adhesion[edit] Morphogenetic Response Triggers. Mechanical Stressers. Stress (mechanics) In continuum mechanics, stress is a physical quantity that expresses the internal forces that neighbouring particles of a continuous material exert on each other. For example, when a solid vertical bar is supporting a weight, each particle in the bar pulls on the particles immediately above and below it.
When a liquid is under pressure, each particle gets pushed inwards by all the surrounding particles, and, in reaction, pushes them outwards. These macroscopic forces are actually the average of a very large number of intermolecular forces and collisions between the particles in those molecules. Significant stress may exist even when deformation is negligible or non-existent (a common assumption when modeling the flow of water). Since ancient times humans have been consciously aware of stress inside materials. The understanding of stress in liquids started with Newton himself, who provided a differential formula for friction forces (shear stress) in parallel laminar flow. along its axis. Internal Stress on Water.
Elastic Stress. Spacial Patterning. Pollutants. Hormones. Hormone formation may arise at localized clusters of specific cells known as endocrine glands, or at other specialized cells with several functions. Hormone synthesis occurs in response to specific biochemical signals induced by a wide range of regulatory systems. In some cases, the rate at which these systems act on a hormone depends on the particular effect or properties of the hormone.
For instance, ionized calcium concentration modulates PTH synthesis, whereas glucose concentration modulates insulin synthesis. Contrarily, regulation of hormone synthesis of gonadal, adrenal, and thyroid hormones is often dependent on a complex set of direct influences and feedback interactions involving the hypothalamic-pituitary axis (See HPA axis, HPG, HPT). Endocrinology is a branch of science concerned with the biosynthesis, storage, chemistry, biochemical and physiological function of hormones and with the cells of the endocrine glands and tissues that secrete them. Hormones as signals[edit]
External Magnetic Fields.