week 2: Human cells, cancer Flashcards
what is gametogenesis?
the production of the gametes
what is spermatogenesis?
the formation of sperm. it is continuous and prolific
hundreds of millions produced each day. each sperm takes about seven weeks to develop.
oogenesis
the development of a mature egg.
this is a prolonged process.
immature eggs form in the female embryo but do not complete their development for years later.
what is fertilization?
it is the formation of a diploid zygote from the haploid egg and sperm.
what is the cleavage
a period with rapid mitotic division without growth.
what is a morula
the compact mass of cells after fertilization.
what is gastrulation?
the cells of the blastula (fluid filled cell) are rearranged into a three layered embryo called the gastrula.
What are the three germ layers produced during gastrulation?
- ectoderm
- mesoderm
- endoderm
describe the ectoderm germ layer
the epidermis of the skin, the nervous system (including brain) and sensory organs.
describe the mesoderm germ layer
the skeleton, muscles, blood vessels, heart, blood and kidneys
describe the endoderm germ layer
lining of internal organs; including those of the digestive system, respiratory system, liver and pancreas.
what happens during the first trimester?
all the major structures are present by 8 weeks, and the embryo is called a fetus
what happens during the second trimester
(3 point)
- the fetus grows and is very active
- the mother may feel fetal movements.
- the uterus grows enough for the pregnancy to become obvious
what happens during the third trimester
the fetus grows and fills the space within the embryonic membranes.
what are the 4 adult tissue types
- epithelial tissue
- connective tissues
- muscle tissue
- nerve tissue
describe epithelial tissue
tightly packed cells, covers internal and external surfaces