Embryology Flashcards
Embryogenesis
Occurs in the Fallopian tube. After fertilization, Fallopian cilia move the fertilized egg to the uterus.
The lysozymes of the acrosome in sperm help it enter the egg.
Fertilization
Embryogenesis
Fertilized egg undergoes rapid division through 8-cell stage, with cells being totipotent.
Cleavage
Embryogenesis
Solid mass of cells that enters the uterine cavity.
Morula
Embryogenesis
The cell mass becomes a hollow cavity and implants into the endometrium (uterine lining).
The outer cells become the placenta and inner cells become embryo.
Blastulation
Embryogenesis
The germ layers and notochord form. First step is formation of primitive streak, which determines midline of body.
Gastrulation
Embryogenesis
The ectoderm is induced by the notochord.
The ectoderm then forms the neural tube, which develops into the brain and spine (central nervous system), and the neural crest cells, which develop into the peripheral nervous system.
Neurulation
Germ layers
Develops into attractive features such as outer appearance (skin, eyes, hair, nails), external orifices (mouth, anus), and “personality” (nervous system).
Ectoderm = Attract-oderm.
Germ layers
Develops into things that move externally (bone, muscle) and internally (lymph, blood, steroid hormones, urinary system including kidneys and gonads).
Mesoderm = Movement.
Germ layers
Develops into internal organs such as GI system, respiratory system, endocrine glands.
Endoderm = Inner tubing or IN-doderm.
Placenta secretes this hormone after implantation to maintain the corpus luteum.
HCG
The corpus luteum secretes these hormones to maintain the uterine lining.
estrogen and progesterone
Stem cell potency
“total” freedom to develop into any cell.
Totipotent
Stem cell potency
“multiple.” Can develop into several different types. Adult stem cells are multipotent.
Multipotent
Stem cell potency
“plural”. Can develop into any cell except placental structures.
Pluripotent
occurs in the embryo when cells commit to a specific type.
cell determination
