Embryogenesis & Development Flashcards
The widest part of the fallopian tube where fertilization occurs is known as ?
Ampulla
What occurs after the penetration of sperm through the cell membrane ?
Cortical rxn (release of Ca2+ ions) -Depolarizes membrane of the ovum to prevent fertilization of ovum by multiple sperm & high Ca2+ increases metabolic rate of zygote
The fertilization of 2 different eggs by 2 different sperm results in what ?
Dizygotic (fraternal) twins
- Each develop its own structures & components
- No more genetically similar than regular siblings
What is the result of a single zygote splitting into 2 ?
Monozygotic (identical) twins
What is the difference between indeterminate & determinate cleavage ?
Indeterminate results in cells that can still develop into complete organisms, while determinate results in cells that are committed to differentiating into certain types of cells
What does the embryo become after several rounds of division (cleavage) ?
Morula (solid mass of cells)
A morula undergoes blastulation, which form the blastula…what is a blastula ?
Hollow ball of cells w/ fluid filled inner cavity (blastocoel)
- mammalian blastula = blastocyst (consists of trophoblast & inner cell mass)
- trophoblast: surrounds blastocoel & gives rise to chorion & placenta
- inner cell mass: protrudes into blastocoel & gives rise to the organism
The extraembryonic membrane that later develops into the placenta is known as ?
Chorion
What structure supports the embryo before functional placenta development, & serves as a site for early blood cell development ?
Yolk sac
What is the difference between the 2 embryonic membranes: allantois & amnion ?
Allantois is involved in fluid exchange btwn. yolk sac & embryo
Amnion surrounds the allantois (filled w/ amniotic fluid); serves as a shock absorber during pregnancy
What does the process of gastulation encompass ?
Gastrula: a small invagination in the blastula
invagination is known as archenteron, and opening is known as blastopore
What’s the difference btwn deuterostomes & protostomes ?
D: blastopore develops into anus
P: blastopore develops into mouth
What all does the ectoderm encompass ?
Integument
Lens of eye
Nervous system (including adrenal medulla)
Inner ear
What all does the mesoderm encompass ?
Musculoskeletal, circulatory, & excretory system
Gonads
Muscular & connective tissue
What all does the endoderm encompass ?
epithelial linings
The ability of 1 group of cells to influence the fate of nearby cells is known as >
Induction
-mediated by inducers that diffuse from organizing cells (organizing to responsive)
What are the features & functions of the process of neurulation ?
- Notochord: rod of mesodermal cells that form along the axis of the organism
- Induce a group of ectodermal cells to fold inward forming neural folds, which surround neural groove
- Neural folds grow & fuse together forming neural tube
- Neural tube gives rise to CNS
- Neural crest cells (@ tip of each neural fold) migrate outward to form PNS
What are the stages and functions of cell specialization ?
Specification: where the cell is reversibly designated as a specific cell type
Determination: cell is committed to a specific lineage, irreversible
Differentiation: cell undergoes changes to develop into determined cell type
Stem cells w/ the greatest potency are known as ?
Totipotent: can differentiate into any cell type
Cells that can differentiate into any cell type EXCEPT for those found in placental structures is known as ?
Pluripotent
Stem cells that can differentiate into multiple types of cells within a particular group are known as ?
Multipotent
What are the different types of cell-cell communications ?
Autocrine: cell signals itself
Paracrine: signal acts on cells in the local area
Juxtacrine: signal sent to cell via linked pathway
Endocrine: signals sent via bloodstream to distant target tissue
What is the diff between necrosis & apoptosis ?
Necrosis is cell death caused by injury, while apoptosis is intentional & programmed
What do fetal blood cells have that increase their oxygen uptake from the mother ?
Fetal hemoglobin (HbF) *gas exchange in fetus occurs via placenta
The umbilical arteries carry blood _______ the ___ to the _____.
away from the fetus to the placenta (deoxygenated)
The umbilical veins carry blood _____ the ____ from the _____.
towards the fetus from the placenta (oxygenated)
What does the fetus construct to direct blood away from developing organs (liver & lungs) ?
Shunts
- Foramen ovale: one way valve that connects right atrium to left (allows blood to flow into left atrium instead of right ventricle)
- Ductus arteriosus: displace leftover blood from pulmonary artery to aorta
- Ductus venosus: redirects blood returning from placenta directly to inferior vena cava
What hormones coordinate the rhythmic contractions of the uterine smooth muscle during birth ?
Oxytocin & prostaglandins
