Embryologic Development of Animals 457 



2. Define (1) zygote, (2) morula, (3) blastula, (4) gastrula, (5) ectoderm, (6) 

 entoderm, (7) blastocoel, (8) blastopore, (9) archenteron, and (10) cleavage. 



3. Contrast micromeres and macromeres as to size, location, rate of division, and 

 functions. 



4. What system is first definitely differentiated in the developing frog? In man? 

 Explain how and why it arises early. 



5. Explain the origin of the notochord and its relationship to the nervous system. 



6. Review the discussion on tissues and tell which tissues arise from each of the 

 three germ layers. 



7. What forces cause certain cells of an embryo to divide and dev^elop at certain 

 times and to rem.ain rather inactive at other times? 



8. Why is it undesirable for all cells of an embryo to divide at the same time? 

 Explain the relationship between this and food supphes, waste accumula- 

 tions, etc. 



9. Explain the role of heredity in determining the time and rate of development 

 of certain tissues at specific periods. 



10. What controls the rate of mitosis in the anterior part of the neural tube, 

 which through enlargements develops into the various regions of the brain? 



11. Can the age of an embryo be approximately determined by the presence of 

 specific embryonic structures? 



12. In what ways do the various stages of the frog embryo and human embryo 

 resemble each other? In what ways do they differ? 



13. Describe the embryologic origin and development of such human tissues and 

 organs as the instructor suggests. 



14. Give a definition and an example of ontogeny, phylogeny, recapitulation 

 (biogenic) theory, and morphogenesis. 



SELECTED REFERENCES 



Arey: Developmental Anatomy (Embryology), W. B. Saunders Co. 



Bailey and Miller: Textbook of Embryology, William Wood & Co. 



Corner: The Hormones in Human Reproduction, Princeton University Press. 



Corner: Ourselves Unborn, Yale University Press. 



Dodds: Essentials of Human Embryology, John Wiley & Sons, Inc. 



Huettner: Fundamentals of Comparative Embryology of Vertebrates, The Mac- 



millan Co. 

 Marshall: Vertebrate Embryology, G. P. Putnam's Sons. 

 McEwen: Vertebrate Embryology, Henry fiolt & Co., Inc. 

 Parshley: The Science of Human Reproduction, W. W. Norton & Co., Inc. 

 Patten: Human Embryology, The Blakiston Co. 

 Patten: Embryology of the Chick, The Blakiston Co. 

 Patten: Embryology of the Pig, The Blakiston Co. 



Potter: Fundamentals of Human Reproduction, McGraw-Hill Book Co., Inc. 

 Richards: Outline of Comparative Embryology, John Wiley & Sons, Inc. 

 Rugh: Experimental Embryology, John Wiley & Sons, Inc. 

 Weiss: Principles of Development, Henry Holt & Co., Inc. 

 Wieman: Introduction to Vertebrate Embryology, McGraw-Hill Book Co., Inc. 



