NURS 220 Lecture Notes - Lecture 2: Noncoding Dna, Messenger Rna, Embryonic Stem Cell
Document Summary
Every second four million cells divide in your body. Replace enire g. i tract every three to four days. At the end of cellular reproducion you have two idenical daughter cells (diploid). Mother cell is gone (disappears) and has become part of the creaion of the daughter cells. Gametogenesis of ovum and sperm divide alleles of chromosome pairs. Ovum is the largest cell in the body receiving more than half the cytoplasm while sperm are very small and they receive much less cytoplasm. External controls of cell division-messengers come from outside the cell and tell it to divide. They atach to receptor cells and use hormones to tell cell to divide. Paracrine chemicals-produced locally by one cell siing close to or next to another cell. Paracrine control-normal negaive feedback to stop cells from reproducing. Internal controls of cell division-genes can control whether a cell undergoes division.
