Chapter 10- Vertebrate Embryology Flashcards
Embryology
Study of the development of a unicellular zygote into a complete, multicellular organism
Cleavage
Series of rapid mitotic divisions– lead to increase in cell number but no growth in protoplasm (total cytoplasm volume remains constant)
Cleavage in relation to cell size and nuclear to cytoplasmic material ratio
smaller cells
increasing ratio of nuclear to cytoplasmic material
cleavage in relation to surface to volume ratio
Increases surface to volume ratio- improves gas and nutrient exchange
morula
What one zygote divides into before turning into a blastula
Blastulation begins when..
the morula develops a fluid-filled cavity called the blastocoel which by the 4th day becomes a hollow sphere of cells called the blastula
The stage where the embryo implants in the uterus is:
The blastula
Gastrula
Once implanted in the uterus, blastula –> gastrula
Three layers of gastrula
Ectoderm
Endoderm
Mesoderm
Ectoderm
Integument (epidermis, hair, nails, and epithelium of nose, mouth and anal canal), lens of eye, retina, and the nervous system
Endoderm
Epithelial linings of the digestive and respiratory tracts (lungs) and parts of liver, pancreas, thyroid, and bladder lining
Mesoderm
Musculoskeletal system, circulatory system, excretory system, gonads, connective tissue throughout the body, and portions of digestive and resp. orgams
Netrulation
process by which regions of the germ layers begin to develop into a rudimentary nervous system at the end of gastrulation.
notochord
A rod of mesodermal cells that develops along the longitudinal axis under dorsal layer of ectoderm
causes ectoderm to bend inward and form groove along dorsal surface of the embryo
Notochord forms into the
neural tube, which gives rise to the brain and spinal cord (central nervous system)