Developmental biology 3 Flashcards
(29 cards)
What does the ectoderm give rise to?
the skin and nervous system
what does the mesoderm give rise to?
the muscle, bone, connective tissues (including blood)
what does the endoderm give rise to?
the gut
what is morphogenesis?
The process by which cells differentiate and form tissues and organs, establishing the body plan
What marks the start of gastrulation in frog embryos?
Invagination of bottle cells at the future dorsal side.
How do bottle cells change shape during invagination?
Actin filaments constrict apically, and the basal side fans out.
What is epiboly?
The thinning and spreading of ectodermal cells over the embryo.
what changes in cells undergoing epiboly?
increased substratum adhesion
What is the archenteron?
A tube formed during involution that becomes the primitive gut
How do mesodermal cells move during gastrulation?
Through convergent extension—narrowing and elongating along the anterior-posterior axis as the archenteron grows inwards
What transformation do mesodermal epithelial cells undergo in sea urchin gastrulation?
EMT (epithelial-to-mesenchymal transition)
What do sea urchin PMCs form?
Skeletal structures
What marks the ventral side in sea urchin gastrulation?
The site of initial invagination and blastopore
what marks the ventral side in frog gastrulation?
the site of sperm entry
How is the archenteron elongated in sea urchins?
Through convergent extension and filopodia pulling by secondary mesenchymal cells
Where is the future mouth in sea urchins?
Where the archenteron contacts the opposite side of the blastocoel
What does the mnemonic Eating Ice Creams In Igloos May Induce Pneumonia stand for?
Epiboly, Intercalation, Convergent Extension, Invagination, Involution, Migration, Ingression, Proliferation
What is intercalation?
Intermixing of cells from two layers into one broader sheet.
What happens in convergent extension?
Tissue elongates by cells intercalating along the axis
What is ingression?
Cells detach from epithelium and move into the ECM
What drives changes in cell shape (such as invagination) during morphogenesis?
The actin-myosin cytoskeleton
What is the Spemann-Mangold organizer?
The dorsal lip of the blastopore that can autonomously induce axis formation.
What experiment proved the organizer’s autonomy?
Grafting the dorsal lip onto a ventral side created a second body axis.
How is the dorsal side determined in frogs?
By sperm entry and subsequent cortical rotation
