Principles of Medical Embryology Flashcards
gamete:
mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote
Embryonic period:
weeks 3 - 8 in humans
teratogen:
cause irreversible, deleterious structural malformations in fetuses
mutagen:
cause changes (mutations) in the genetic material of cells
what is Gametogenesis
formation of a gamete
Spermatogenesis:
formation of male gametes
- Occurs at puberty and continues throughout life
Oogenesis:
formation of female gametes
- Primary oocytes begin meiosis by weeks 28-30 but arrest in prophase until puberty
what occurs during fertilisation
Union of gametes - fusion of sperm and oocyte to form a zygote
what is cleavage
Period of rapid mitotic cell division with no increase in size
what is formed during cleavage
Formation of morula then blastocyst (days 1-4)
what is Gastrulation
Formation of the germ layers - ectoderm, mesoderm, endoderm
what is established during gastrulation
the Body axis
what is embryonic folding
Formation of the body plan
what is Organogenesis
Formation of organs and organ systems
- Basis in place by end of embryonic period, development continues through fetal period
describe the Fetal period
- From week 9 until birth
- Growth, weight gain
- Tissues mature and become functional
- Overt sexual differentiation
- Bone laid down; connections made in CNS
