Developmental Biology Flashcards
Cleavage
Series of rapid mitotic divisions, increasing nuclei to cytoplasm, increases surface-area-to-volume ratio for improved exchange
Morula
Solid ball of embryonic cells
Blastulation
Morula develops a fluid-filled cavity called the blastocoel
Blastula
Hollow sphere of cells
Trophoblast
Outer layer of the blastula, role in the implantation of the blastula in the uterus
Ectopic Pregnancy
Embryo implants outside the uterus
Amnion
Thin, tough membrane containing a watery fluid called the amniotic fluid, shock absorber
Chorion
Membrane that completely surrounds the amnion, assists with the transfer of nutrients
Allantois
Third membrane, develops as an outpocketing of the gut
Yolk Sac
Site of early development of blood vessels, associated with the umbilical vessels
Ectoderm
Integumentary system, lens, retina, nervous system
Mesoderm
Musculoskeletal, circulatory, excretory, connective tissue
Endoderm
Epithelial lining of the digestive and respiratory tract, bladder lining
Neurulation
Germ layer develops into a rudimentary nervous system
Neural Tube
Gives rise to the brain and spinal cord
Neural Crest Cells
Cells at the top of each neural fold, cells migrate and give rise to the peripheral nervous system
Spina Bifida
Neural tube does not close properly
Organogenesis
The body organs begin to form, cells differentiate and migrate
Gametogenesis
Eggs/Sperm develop
Teratogens
Drugs, alcohol, tobacco
Vertical Transmission
Mother passes an infection directly to the developing offspring
Angiosperm Fertilation
Double Fertilization, One sperm fertilizes and one sperm forms the endosperm
Sporophyte
Produces haploid spores via meiosis
Gametophyte
Produces gametes via mitosis
Epicotyl
Precursor of the upper stem and leaves
Cotyledon
Seed leaves, dicots have two seed leaves
Hypocotyl
The lower stem and root
Endosperm
Feeds the embryo in angiosperms
Seed Coat
The outer covering of the ovule
Germination
Seeed sprouting into a seedling
Meristem Cells
Growth in higher plants, undifferentiated
Apical Meristem
Tips of roots/stems, growth in length
Lateral Meristem
Between the xylem and phloem, permits growth in diameter
