Surface enlargement
An increase in surface area is the increase in the limitation of a system against the external medium, even with a constant volume . The total surface increases with constant volume u. a. to when a body is broken up into parts, when a sphere is deformed, when a Platonic solid is converted into another with a lower number of areas and when a cube is converted into a different type of cuboid . In general, the total surface area increases while the volume remains the same when a compact body is transformed into an elongated, flatter, articulated or differentiated body, cf. also degree of division . The total surface area increases with decreasing volume, if a body is hollowed out by removing material, for example by drilling, so that the newly created surface in the previous interior exceeds the part of the previous surface that has been removed.
Surface enlargement is an important function and development principle in biology and technology .
biology
Based on surface enlargement in zoology u. a. the spatial structure of the gray matter , the folding of the cerebral cortex , the gill breathing , the formation of the pulmonary alveoli and the blood capillaries . In the latter three, the area of gas exchange is increased and breathing is optimized. The folding of the cerebral cortex is the subject of topistic brain research . The shape of erythrocytes is determined by the largest possible surface-to-volume ratio. It is a relative increase in surface area. Phagocytes, as a preliminary stage of phagocytosis, ward off invading pathogens by enlarging the surface area and invaginating the surface membrane . A botanical example is the plant leaf , which is enabled by a large surface to absorb as much light as possible. Cytological examples are microvilli on intestinal epithelial cells for better exchange of substances, the folded inner mitochondrial membrane and thylakoids in chloroplasts .
technology
Examples from technology are radiator fins and perforated brake discs , which should each give off as much heat as possible, chopped frozen food that should absorb as much heat as possible, sugar and salt in granular form for rapid solubility in water, piers to accommodate as many passenger boarding bridges and shelf systems as possible in libraries, warehouses, archives and collections of Aservates.
Web links
Individual evidence
- ↑ Degree of cephalization, topistic brain research . In: Alfred Benninghoff , Kurt Goerttler : Textbook of Human Anatomy. Shown with preference given to functional relationships. 7th edition. 3rd volume. Nervous system, skin and sensory organs. Urban and Schwarzenberg, Munich 1964, pp. 226–228.
- ↑ Form of erythrocytes . In: Hermann Rein , Max Schneider : Introduction to the human physiology . 15th edition. Springer, Berlin 1964, p. 22.
- ↑ surface membrane . In: Hans Ulrich Zollinger : Pathological Anatomy . Volume 1. General Pathology. Georg Thieme, Stuttgart 1968, p. 147.