Embryogenesis and Development Flashcards
What sex are embryos by default?
female <3
Fertilization usually occurs in the…?
ampulla
Acrosomal apparatus
the first sperm to come in contact with the secondary oocyte’s cell membrane, forms a tubelike structure
Cortical reaction?
after the sperm penetrates the cell membrane, a release of calcium ions occurs; the calcium ions depolarize the membrane of the ovum, prevents fertilization of the ovum by multiple sperm cells and increased calcium concentration increases the metabolic rate of the newly formed zygote
Cleavage (for cells)
as the zygote moves to the uterus for implantation, the zygote undergoes rapid mitotic cell divisions in a process called cleavage!
indeterminate and determinate cleavage
indeterminate cleavage
cells that can still develop into complete organisms
determinate cleavage
results in cells with fates that are already determined; committed to differentiating into a certain type of cell
morula
embryo becomes a solid mass of cells
blastula
when morula undergoes blastulation, in which the blastula, a hollow ball of cells with a fluid-filled inner cavity known as a blastocoel; mammal’s are called blastocyst
chorionic villi
microscopic fingerlike projections that penetrate the endometrium
yolk sac
what the embryo is supported by until the placenta is fully functional
allantois
involved in early fluid exchange between the embryo and the yolk sac, ultimately, the umbilical cord is formed from remnants of the yolk sac and the allantois, allantois is surrounded by the amnion, a thin, tough membrane filled with amniotic fluid
gastrulation
generation of three distinct cell layers
archenteron
membrane invagination into the blastocoel, later develops into the gut, opening of this is called the blastopore, turns into the anus (in deuterostomes), like humans, in protostomes, it turns into the mouth
ectoderm
outermost layer, gives rise to the integument, including the epidermis, hair, nails, and the epithelia of the nose, mouth, and lower anal canal, the lens of the eye, nervous system (including adrenal medulla), and inner ear are also derived from ectoderm
mesoderm
develops into several systems including the musculoskeletal, circulatory, and most of the excretory systems, gives rise to gonads as well as the muscular and connective tissue layers of the digestive and respiratory systems and the adrenal cortex
endoderm
epithelial linings of the digestive and respiratory tracts, including the lungs, pancreas, thyroid, bladder, and distal urinary tracts, as well as parts of the liver, are derived from endoderm
selective transcription
only the genes that are needed for a particular cell are transcribed
induction
ability of one group of cells to influence the fate of nearby cells
inducers
diffuse from organizing cells to the responsive cells, chemicals are responsible for processes such as the guidance of neuronal axons
neurulation
development of the nervous system, can occur once the three germ layers are formed
teratogens
substances that interfere with development ex. alcohol or high blood glucose
specification
cell is reversibly designated as a specific cell type
determination
the commitment of a cell to a particular function in the future
