NBDHE- Embryology and histology (StudentRDH) Questions And Answers A+

NBDHE- Embryology and histology (StudentRDH) Questions And Answers A+ Embryology - ANS-study of prenatal development, from fertilization to birth. Prenatal development - ANS-usually divided into trimesters (each lasting 3 months), but can also be divided into three periods (preimplantation, embryonic, and fetal) marked by changes in the development. -First trimester includes preimplantation and embryonic period Preimplantation period` - ANS-first week of conception. Embryonic period - ANS-week 2 through 8 Fetal period - ANS-week 9 through birth Fertilization - ANS-Formation of the egg (zygote) by the union of ovum and sperm. Zygote - ANS-receives half of its chromosomes from the female and half from the male (23 chromosomes each, creating 46 chromosomes). After fertilization, the zygote (egg) undergoes mitosis (individual cell division). -After the initial cleavage into 2 cells, the cell divides multiple times leading to a solid ball of cells known as the morula (16-32 cells, resembles a blackberry). - ANS- Zygote becomes a blastocyte _with successive cell divisions. As the blastocyst (hollow in the middle) continues cell duplication/division, it travels down to the uterus. - ANS-