Reflex is a reaction of a living organism to an irritant, which takes place with the participation of the nervous system.
It consists of processes:
Receptor perception of irritation
– transmission of excitation (in hydra – from cell to cell, because the nervous system is diffuse)
– response (in hydra – compression in a lump, with the participation of epithelial – muscle cells).
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.