* Organs are complex structures made of different tissues. These tissues are, in turn, made up of various types of cells that work together to perform specific functions.
* Cells don't change their fundamental type. While cells can specialize and differentiate to become various cell types within a tissue, they don't fundamentally change into different cell lineages.
* The excretory system develops from multiple tissues. The kidneys, for example, develop from mesoderm (a germ layer during embryonic development) and involve several different cell types like epithelial cells, smooth muscle cells, and blood vessel cells.
Here's a more accurate way to think about the development of the excretory system:
1. Embryonic Development: During embryonic development, specialized cells arise from different germ layers (ectoderm, mesoderm, and endoderm). These cells differentiate into various cell types.
2. Tissue Formation: These specialized cells then interact and organize to form tissues like epithelial tissue, connective tissue, muscle tissue, and nervous tissue.
3. Organ Formation: Different tissues then come together in specific arrangements and proportions to form organs. In the case of the excretory system, the kidneys, ureters, bladder, and urethra are formed from these tissues.
In summary: The excretory system doesn't form from single cells transforming into organs. It's a complex process of cell differentiation, tissue formation, and organogenesis, where different cell types work together to build a functional system.
