Animal Development - Chapter 47 Flashcards
Classical embryology
description of development in model organisms
induction
one type of tissue influences the development of another tissue
Development Stages
Fertilization
Early Cleavages
Blastula (hollow ball of cells)
Gastrulation (forms the gastrula)
Organogenesis (formation of organs)
Ectoderm
epidermis, nervous system
Mesoderm
skeleton muscles
Endoderm
digestive, reporductive
Underlying mechanisms of organogenesis
Organosgenesis are localized changes
cell migration
cell signaling between different tissues
cell shape changes genrating new organs
Cell movement
reorganize cytoskeleton
microtubules and microfilaments (actin)
(cells crawl using the cytoskeleton fibers to extend (extension) and retract (convergence) extensions
Amniotes
reptiles
birds
mammals
all have a way of developing in “watery” environments
4 extraembryonic membranes of amniotes
evolved as adaptation to terrestrial envroniment
Amnion
Chorion
Allantosis
Yolk Sac
Amnion
protects embryo in a sac
Chorion
lines the inner surface of the shell (which is permeable to gases) and participates in exchange of O2 and Co between embryo and outside air
Allantosis
stores metabolic wastes (mostly uric acid) of the embryo and as it grows larger, also participates in gas exchange
Yolk Sac
contains yolk - the sole source of food until hatching
Placental mammal development
cleavage in oviduct produces blastocyst
Placenta
produces progesterone beginning in the 2nd trimester (as hCG declines and corpus luteum atrophies)
(no direct connection between maternal and fetal blood vessels)
Human fetal development
zygote -> embryo (>2cells) -> fetus (8 weeks)
positive feedback in labor
3 stages of labor
- dilation of cervix
- expulsion - delivery
- delivery of placenta
Teratogenesis
environment causes a developmental abnormality
description of development in model organisms
Classical embryology
one type of tissue influences the development of another tissue
induction
Fertilization
Early Cleavages
Blastula (hollow ball of cells)
Gastrulation (forms the gastrula)
Organogenesis (formation of organs)
Development Stages
epidermis, nervous system
Ectoderm
skeleton muscles
Mesoderm
digestive, reporductive
Endoderm
Organosgenesis are localized changes
cell migration
cell signaling between different tissues
cell shape changes genrating new organs
Underlying mechanisms of organogenesis
reorganize cytoskeleton
microtubules and microfilaments (actin)
(cells crawl using the cytoskeleton fibers to extend (extension) and retract (convergence) extensions
Cell movement
reptiles
birds
mammals
all have a way of developing in “watery” environments
Amniotes
evolved as adaptation to terrestrial envroniment
Amnion
Chorion
Allantosis
Yolk Sac
4 extraembryonic membranes of amniotes
protects embryo in a sac
Amnion
lines the inner surface of the shell (which is permeable to gases) and participates in exchange of O2 and Co between embryo and outside air
Chorion
stores metabolic wastes (mostly uric acid) of the embryo and as it grows larger, also participates in gas exchange
Allantosis
contains yolk - the sole source of food until hatching
Yolk Sac
cleavage in oviduct produces blastocyst
Placental mammal development
produces progesterone beginning in the 2nd trimester (as hCG declines and corpus luteum atrophies)
(no direct connection between maternal and fetal blood vessels)
Placenta