BIOL 031 Lecture Notes - Lecture 6: Chorionic Villi, Neuromuscular Junction, Somatic Nervous System
Document Summary
Fusion of sperm with oocyte induces meiosis ii: oocyte ovum. Chromosomes combine, dna is replicated, mitosis occurs. Blastocyst is formed with trophoblast and inner cell mass: forming embryo. Trophoblast invade endometrial tissue, forming placenta: secrete enzymes that break down endometrial tissue and draw nutrients into the embryo, secretes human trophographic hormone (hgt) which produces progesterone. Chorionic villi penetrate endometrium, become surrounded by maternal blood. Exchange of gases, nutrients between maternal and fetal blood. Placenta secretes estrogen and progesterone throughout pregnancy. In females, oocytes are formed in the ovaries. Reproductive function is cyclical: the ovarian cycle (follicular and luteal, the uterine cycle (menstrual, proliferative and secretory phases) Female cycles are regulated by the gonadotropins. Efferent neurons of the somatic nervous system = motor neurons: controls motor functions. Neuromuscular junction = the synapse between a motor neuron and a muscle fibre: axons of neurons and muscles meet together. Motor end plate = specialized muscle membrane at junction.