42 WJEC Biology AS Level - Marianne Izen - 2nd Edition Flashcards
Tissue (Key Term)
Tissue: A group of cells working together with a common function, structure and origin in the embryo.
What are stem cells?
Some cells in the adult remain unspecialised and are stem cells, with the potential to make other cell types, eg stem cells in bone marrow can differentiate into all types of blood cell.
What happens to cells near each other in the embryo?
Cells near each other in the embryo often differentiate in the same way and group together as a tissue.
What are the various tissue types in mammals?
Mammals have several tissue types including epithelial, muscular and connective tissue.
What does epithelia tissue do?
Epithelial tissue forms a continuous layer, covering or lining the internal and external surfaces of the body.
Does epithelia have blood vessels or nerve endings?
Epithelia have no blood vessels but may have nerve endings.
Where do epithelial cells sit on?
The cells sit on a basement membrane, made of collagen and protein and they vary in shape and complexity.
What functions do epithelial cells have?
They often have a protective or secretory function.
What is the simplest form of epithelial cells?
The simplest form is simple cuboidal epithelium, in which cells have a cube shape (cuboidal) and the tissue is just one cell thick (simple).
Where does the simplest form of epithelial cells found?
It occurs in the proximal convoluted tubule of the kidney nephron and the ducts of salivary glands.
What are type of cells in columnar epithelium?
Columnar epithelium has elongated cells.
Which type of columnar epithelium have cilia?
Those lining tubes that substances move through, such as the oviduct (fallopian tube) and trachea, have cilia.
What does this picture show?
Draw a labelled diagram of cuboidal epithelium.
What does this picture show?
Draw a labelled diagram of ciliated columnar epithelium.
