JH+development+HW

Human Life Cycle 16.1 p. 320 INSERTING FIGURES IS ALWAYS A GOOD THING. (1) How many chromosomes does a mother contribute to a new individual? 23 A father? 23 (2) Where does meiosis occur in males? testes in females? ovaries (3) Compare and egg cell to a sperm cell. the egg is much bigger than the sperm and the sperm swims (4) What is the difference between meiosis and mitosis. meiosis is reduction division and mitosis is duplication division

Development Chapter 17 17.1 (5) Describe in detail how fertilization occurs (6) What is polyspermy and how is prevented during fertilization? 17.2 (7) Describe the processes involved in development. (8) What are the extraembryonic membranes and what is their role? (9) What happens during pre-emrbyonic development?
 * it is the union of a sperm and an egg to form a zygote the first cell of the new individual
 * Polyspremy is the entrance of more than one sperm into an egg and is prevention depends on the eggs membrane and its placement in pellucida
 * Cleavage - their is first a zygote and then it divides into more and more cells and each cells gets the right amount of chromesomes
 * Growth - the daughter cell increase in size
 * Morphogenesis - the embryo begins to assume different shapes
 * Differentiation - cells begins to become specific structures, the nervous system comes first
 * Chorion - develops into the fetal half of the placenta, provides nourishment
 * Allantois - its like the fetal yoke sack it extends away from the embryo, later gives rise to the urinary bladder
 * Yolk sac - first embryonic membrane to develop, serves as food for the embryo
 * Amnion - enlarges as the embryo enlarges contains fluid to protect the embryo
 * Ovulation
 * fertilization
 * cleavage
 * morula
 * early blastocyst
 * implantation

(10) What happens during embryonic development? First their is just a disk with a yolk, then the umbilical cord forms, and then at 35 days it has a head and a tail region (11) What are the primary germ layers and what body structures come from each layer?
 * Ectoderm - epidermis of skin; lining of oral cavity and rectum; nervous system
 * Mesoderm - skeleton; muscles; urinary system; reproductive system
 * Endoderm - lining of digestive tract and respiratory tract; and the glands of these organs