Unit 5: Vertebrate Development Flashcards
(24 cards)
What is a zygote?
A fertilized egg cell formed by the union of sperm and egg
What is a blastula?
A hollow ball of cells resulting from cleavage of the zygote
What is a gastrula?
A stage where the three germ layers form via cell migrations
What is a neurula?
The stage where the neural tube begins forming (neurulation)
What is cleavage in development?
Rapid mitotic divisions after fertilization with no growth between divisions
What is an organizer in development?
A signaling center (e.g., Spemann-Mangold Organizer) that patterns the embryonic body plan
What is involution?
Inward movement of an expanding outer layer of cells during gastrulation
What is epiboly?
Expansion of one cell sheet over other cells
What happens during fertilization?
Fusion of haploid gametes into a diploid zygote, triggering polarity and cytoplasmic changes
What is the result of cleavage?
Formation of a blastula with a blastocoel
What is Cleavage? What are the two types and examples of each?
Partitioning of cytoplasm via rapid cell divisions
Holoblastic (frogs, mammals), Meroblastic (birds, fish)
What happens during gastrulation?
Germ layers form through cell movements like involution, invagination, and epiboly
What happens during neurulation?
Neural tube forms from ectoderm; neural crest cells form PNS and other tissues
What is the Spemann-Mangold Organizer?
A region that can induce a second body axis and secretes BMP inhibitors
How does neural induction occur?
BMP inhibition by Chordin, Noggin, and Follistatin causes ectoderm to become neural tissue
What is the role of BMP in development?
BMPs promote epidermis; inhibition leads to neural tissue formation
What are the cleavage patterns of Amphibians, Fish/Birds & Mammals
Amphibian: Holoblastic, unequal—displaced to animal pole due to yolk
Fish/Birds: Meroblastic, discoidal—cleavage occurs in a small disc on top of yolk
Mammals: Holoblastic, rotational—includes compaction and inner cell mass formation
What does the ectoderm form?
Skin, CNS, PNS, eyes, enamel
What does the mesoderm form?
Muscle, skeleton, blood, kidneys, gonads
What does the endoderm form?
Digestive lining, liver, pancreas, lungs
What is gastrulation?
Formation of the three primary germ layers
What is neurulation?
Development of the central nervous system
What is induction?
Tissue communication to determine cell fate (e.g., neural induction)
What is morphogenesis?
Shaping of tissues and organs into final structures
