01:119:116 Lecture Notes - Lecture 17: Blastula, Fetus, Ectoderm

• School: Rutgers University
• Department: Biological Science
• Course: 01:119:116
• Professor: Professor Beal

Document Summary

I. outcomes: compare gastrulation between a sea urchin, a fog, a chicken, and a human, describe the process of development from fertilization through birth/hatching, cc human trimesters of pregnancy. A. in echinoderms, mammals, and annelids: little yolk, holoblastic, blastocoel forms centrally, blastomeres often of similar size. B. in birds, other reptiles, many fishes, and insects: substantial yolk, cleavage furrow cannot pass through yolk, meroblastic- cleavage only where no yolk. A. following cleavage: cell cycle returns, rate of mitosis slows. B. morphogenesis: morphogenesis- cellular and tissue-based process by which animal body takes shape, occurs during, gastrulation- process of forming a gut, organogenesis- process of forming organs. C. four different paths: deuterstomes -, phylum echinodermata -> sea urchins, phylum chordata -> aquatic eggs -> frogs, phylum chordata -> placenta -> eggs -> chicks, phylum chordata -> amniotes -> placenta humans. A. definition: gastrulation- morphological process by which hollow blastula becomes layered embryo (gastrula). B. 3 embryonic germ layers (diploblastic (have all 3 layers) versus triploblastic: ectoderm, endoderm, mesoderm.