Water is part of the cytoplasm of cells, blood and interstitial fluid. It serves as a solvent for all nutrients entering the body and metabolic products, as well as a medium for all chemical reactions associated with metabolism. Minerals along with water ensure the preservation of the colloidal state of the cell cytoplasm, create a certain osmotic pressure, participate in the regulation of acid-base balance, and play a large role in all metabolic processes. Minerals are the main material for building bone tissue, are part of the nervous and some other tissues, as part of enzymes, hormones, accelerate the course of many chemical reactions. Water and minerals must constantly enter the body, as they are excreted in large quantities with urine and feces. Minerals are especially needed for growing animals and pregnant females. The most important macroelements necessary for animals include calcium, phosphorus, sodium, chlorine, potassium, magnesium, sulfur; trace elements – iron, copper, cobalt, iodine, manganese, zinc, etc. The lack of water and minerals leads to diseases, and sometimes to the death of the animal. The center of regulation of water-salt metabolism is located in the diencephalon.
Vitamins are organic substances of various chemical nature. They are neither a structural material for building tissues, nor a source of energy, but they are part of many enzymes and activate the main enzymatic processes, affect the regulation of metabolic processes. Participate in the breakdown of nutrients, the synthesis of cytoplasm, complement and enhance the action of other nutrients. Lack or absence of vitamins in the diet leads to animal diseases.
Thermoregulation. All mammals and birds have a constant body temperature, independent of ambient temperature. In cattle, it ranges from 37.5–39.5 ° С, in sheep – 38.5–40, horses – 37.5–38.5, pigs – 38–40, chickens – 40.5–42 , in ducks – 41–43 ° С. Thermoregulation is a set of physiological processes in the animal’s body, aimed at maintaining a constant body temperature with a changing ambient temperature. Thanks to this, the necessary conditions for the occurrence of chemical reactions in the body that underlie its life are provided.
Thermoregulation is maintained as a result of the equilibrium between two processes: heat generation and heat transfer. Heat in the body is formed in the process of metabolism during the breakdown of proteins, fats, carbohydrates. Part of it is spent on the needs of the animal, the rest is allocated. Heat transfer by the body occurs through heat conduction (contact of the animal’s body with the floor, ground, litter, etc., which have a lower temperature), convection (heat transfer from the surface of the body to the surrounding air), heat radiation, or radiation (emission from the surface skin of infrared rays, carrying thermal energy), and evaporation of moisture from the surface of the body and respiratory tract. The center of regulation of heat is in the diencephalon. Interacting with the higher parts of the brain, it regulates the temperature of the body by changing the heat transfer to the external environment,
The regulation of heat generation and heat transfer is quite diverse. For example, in winter, the metabolic rate increases, narrowing of the capillaries is observed in the skin, and sweating decreases. As a rule, at the end of summer and autumn, animals accumulate subcutaneous fat, their hair becomes longer. Conversely, in the summer, the metabolism decreases slightly, the activity of sweat glands increases, and the respiratory rate increases.
Reactivity is the property of living matter to perceive irritations from the external environment and respond to them. Reactivity is provided by receptors of the nervous system that perceive irritation. Using the nervous system, irritations are analyzed and synthesized, transformed into sensations and transmitted to the muscle system or glands, which serve as executive organs and directly provide the body with a response to irritation.
Reproduction – the body’s ability to reproduce, preserve the species and life on Earth, is carried out by a system of reproductive organs.