Embryogenesis and Development Flashcards
Acromosomal apparatus
Tube that extends to and penetrates the cell membrane from sperm
Cortical reaction
Release of calcium ions after penetration of sperm through cell membrane
Depolarize membrane of ovum to prevent fertilization of multiple sperm and increase metabolic rate of zygote
Create fertilization membrane
Dizygotic/fraternal twins
Fertilization of two different eggs from one ovulatory cycle by two different sperm
Separte placenta, chorion, and amnioni
Monozygotic/Identical twins
Single zygote splits into two
Chorion/amnion types
Cleavage
Zygote undergoes rapid mitotic cell division while moving to uterus for implantation
Zygote must be
Unicellular, after it is an embryo
Indeterminate cleavage
In cells that still develop into complete organisms (identical twins came from a indeterminately cleaved cell)
Determinate cleavage
Cell fate already determined, committed to differentiating into certain cell types
Morula
Solid mass of cells after after divisions
Blastulation
Forms a hollow ball of cells with a fluid-filled inner cavity called a blastocoel
Trophoblast
Surrounds blastocoel and gives rise to chorion and placenta
Inner cell mass
Of blastula, produdes into blastocoel and gives rise to organism
What does the embryo implant as?
Blastula
Chorion
Extraembryonic membrane that develops into the placenta
What does the umbilical cord contain?
Two arteries and one vein
Artery- deoxygenated blood
Vein- Oxygenated blood
Chorionic villi
Fingerlike projections that penetrate endometrium that support fetal gas exchange
Yolk sac
Early blood cell development
Supports embryo before placenta
Allantois
Early fluid exchange between embryo and yolk sac
Amnion
Surrounds allantois which is a membrane filled with amniotic fluid (shock absorber)
Gastrulation
Generation of three distinct cell layers
Archenteron
Membrane of invagination of gastrula that develops into the gut
Blastopore
Opening of archenteron
Deuterosomes
Humans, blastopore develops into anus
Protosomes
Blastopore develops into mouth
Ectoderm
Outermost layer
Epidermis, hiar, nails, epithelia, nervous system, inner ear
Mesoderm
Musculoskeletal, circulatory, excretory, gonads
Endoderm
Epithelial linings of digestive, respiratory tracts
Pancreas, thyroid, bladder, urinary, liver
Where is the adrenal cortex derived from?
Mesoderm
Where is adrenal medulla derived from?
Ectoderm
Neurulation
Development of the nervous system after the germ layers are formed
Notochord
Rod of mesoderm cells forms along the long axis of organism
Neural folds
Notochord induces ectodermal cells to move in and produce a neural tube
Neural crest cells
Migrate outward to form peripheral nervous system
Teratogens
Substances that interfere with development causing defects or death- genetics changes effects
Morphogens
Molecules that cause nearby cells to follow particular development
Pluripotent
After formation of germ cell layers, still differentiate into any cell except those found in placental structures
Multipotent
Most specialized stem cells
Paracrine cells
Act on cells in a local area v. endocrine that travel
Senescence
Biological aging
What do telomeres have a high concentration of?
Guanine and cytosine
Do maternal and fetal mix blood?
No
Where is the higher partial pressure of oxygen, maternal or fetal blood?
Maternal
What organs do not serve significant function prior to birth?
Lungs and liver, shunts blood away while these develop
Foramen ovale
One-way valve taht conects right atrium to left atrium (higher pressure right side
Ductus arteriosus
Shunts leftover blood from pulmonary artery into aorta
When are most organs formed?
In first trimester by the end of 8 weeks
