In animals, in the process of evolution, organs were formed that make up organ systems:
1. Integumentary system – separates the body from the environment, protects against possible negative influences, regulates body temperature.
2. The musculoskeletal system – provides movement and location of the body in space. May protect internal organs from damage.
3. Respiratory system – provides the body’s gas exchange, that is, the removal of carbon dioxide and oxygen supply.
4. Digestive system – provides preparation of consumed food for its assimilation by the body, breaking down complex substances to simpler ones.
5. Circulatory system – carries out the movement of blood through the body, thus saturating its cells with oxygen and nutrients.
6. Excretory system – removes harmful metabolic products from the body.
7. Nervous system – analyzes information from the environment and its internal organs, provides a response to this information.
8. The sensory system – the system of the senses – perceives information from the environment.
9. The reproductive system – ensures the reproduction of organisms.
Each organ in the system has a characteristic structure and performs its functions.
An organ is a constituent part of the body that occupies a certain position, has a certain structure and performs a certain function.
Animals have a clear body symmetry. If the body can be divided into at least 2 mirror parts, then it is symmetrical.
Radial (radial) symmetry is a symmetry that allows you to draw several planes through the body of an animal, dividing it into equal parts by each plane.
Bilateral (bilateral symmetry) is a symmetry that allows one plane to be drawn through the body of an animal, which divides it into 2 equal halves.
The presence of a body cavity is characteristic of animals.
Body cavity – the space located between the walls of the body and internal organs. Allocate body cavities:
1. Intestinal – a cavity delimited by the wall of the body from the environment.
2. Primary – filled with cavity fluid, which freely washes the internal organs.
3. Secondary – a cavity in which organs are separated from the walls of the body by a layer of cells.