Stephanie'sChapter7

__ Chapter 7 Continuity Through Development __ __ Development (7.1-7.3p159-p165) __ Zygote – the diploid product of the union of haploid gamete in conception; a fertilized egg Development – cell division, growth, and differentiation of a cell from embryonic layers into all the tissues and organs of the body; later changes with age, including changes like puberty. Differentiation – the process by which new cells specialize and become different in appearance and function from their parent cells Cleavage – the process of cell division in animal cells, characterized by rapid cell divisions without growth occurs during early embryonic development and that centers the zygote into a ball Blastula – the term for the hollow ball made of hundreds of cells Gastrula – an early embryo at the stage when infolding of the cells from the outside occurs *all cells are the same it is the genes that are active in them *interaction between different cell types also can play an important role in cell differentiation (Example: during eye development the cells of the embryonic brain divide and expand until they contact the skin ectoderm) __ Animal Development (7.4-7.6 p165-p170) __ *some animals develop independently from their parents(like frogs where the mother deposits the eggs and the father deposits a large amount of sperm over the eggs) *mammal embryos develop within their mothers Placenta – the nutrient rich uterus lining Umbilical cord – the way the embryo attacks itself to the placenta Amnion – a sac or membrane, filled with fluid that encloses the embryo of a reptile, bird or mammal Amniotic fluid – the liquid that bathes an embryo or fetus Fetus – what the embryo is called after 12 weeks of development __ Cancer (7.7-7.8 p170-p172) __ *in cancer the control over the cell to stop dividing is lost *cancer cells divide without limits Tumor – the name for the cell growth caused by cancer Benign – is the name given to tumors that stay near their origins Malignant tumors – ones that continue to divide and spread to other places in the body Oncogenes – a gene found in viruses or as part of the normal genome that is crucial for triggering cancerous characterises