510-2 Flashcards
When does fetal development occur?
9-38 weeks
How long is embryonic development?
8 weeks
What is the ampulla?
Region of the Fallopian tube where fertilization occurs (12-24hrs)
What is ovulation?
When an oocyte is released from an ovary and swept into the Fallopian tube by ciliated epithelia. Each ovary ovulates every other month.
What is follicle stimulating hormone (FSH)?
Stimulated the follicle to grow. This hormone is often used to treat women with infertility issues because it stimulates the growth and production of multiple oocytes.
What is the corona radiata?
The first layer of protection that a sperm must break through.
What is the zona pellucida?
The second layer the sperm must break through. This layer is like an shell composed of glycoproteins.
What is the acrosome?
Vesicle in the tip of the sperm that has digestive enzymes used to break down the zona pellucida (acrosome reaction)
What is polyspermy?
When more than one sperm fertilizes an egg. This results in zygot death because of the mismatched chromosomes (69).
What are the 3 stages of oocyte penetration?
Stage 1: sperm penetrates corona radiata
Stage 2: acrosome reaction as sperm breaks through zona pellucida
Stage 3: sperm breaks through oocyte membrane and loses its own membrane triggering the zona reaction
What is the zona reaction?
When a sperm penetrates the oocyte membrane a calcium mediated change in the zona pellucida prevents other sperm from fertilizing the egg.
What is a zygote?
A fertilized egg (12-24 hrs)
What is pluripotency?
Early stage cells can differentiate into a variety of things but lose the potential to differentiate with each cell division because the environment changes (especially after compaction during the 8 to 16 cell transition)
What is a blastomere?
A cell in the 2, 4, 8, or 16 cell zygote
What is a morula?
Solid ball of blastomeres. Forms around the 4th day when the zygote is entering the uterus.
What is compaction?
Occurs during the 8 to 16 cell transition when cells make tight and gap junctions.
What is paracrine?
Substance produced by one cell that affects another cell (endocrine= paracrine that travels in the blood)
What is autocrine?
Substance produced by a cell that affects itself
What is a blastocyst?
A blastocyst draws fluid into its blastocele and two layers of cells result: trophoblast and embryoblast. This occurs around 4.5 days.
What is an embryoblast?
Layer in the blastocyst that will give rise to the embryo
What is the trophoblast?
Outside layer of the blastocyst that will give rise to the placenta
What are the 3 layers of the uterus?
- ) perimetrium- thin outer membrane
- ) myometrium- muscular middle layer
- ) endometrium- vascular middle layer with mucous glands
What is implantation?
Growth of the trophoblast into the endometrium (penetrates basement membrane). Usually happens around 6th day
What is the syncytiotrophoblast?
Outer layer of the trophoblast with vague cell boarders to aid in blood transfer between mother and fetus
What is the cytotrophoblast?
Inner layer of trophoblast composed of large single cells
What are the two layers of the embryoblast?
Epiblast (will form the embryo) and Hypoblast (will form the yolk sac)
What is the extra embryonic coelom?
Cavity between the hypoblast and trophoblast that takes in fluid to push yolk sac and trophoblast away from eachother and allows for the chorion to develop
What is the chorion?
Produces human chorionic gonadotropin (hCG) which keeps the corpus luteum alive and producing progesterone and estrogen to keep the uterus pregnant (used in pregnancy detection)
What is gastrulation?
Process of the development of 3 germ layers: ectoderm, mesoderm, and endoderm. Takes place from day 13-19.
What does ectoderm give rise to?
Skin, mouth lining, enamel, nervous system
What does mesoderm give rise to?
Muscle, bone, blood, lymphatic system, spleen, lungs, heart, reproductive system, and excretory system
What does endoderm give rise to?
Lining of the gut, liver, pancreas, bladder, thyroid, parathyroid, and lungs
What is mesenchyme?
Undifferentiated connective tissue
What is the primitive streak?
Extends from the primitive node caudally. Is controlled by the gene nodal. The primitive node cells produces transforming growth factor B and bone morphogenic protein 4 that stimulate mesoderm growth.
What is Fibroblast Growth Factor 8?
Transcription factor that controls the inward migration of cells during gastrulation
What are chordin and noggin?
They are expressed by the primitive node and direct differentiation of the mesoderm into the notochord and somites. Play an important role in establishing anterioposterior axes.
What did the Hans Spemann experiment show us?
Transplanting the dorsal lip of a blastopore onto another embryo organizes the growth of another head
What is goosecoid?
Transciption factor that stimulates chordin to signal for the production of cranial mesoderm. If over expressed can lead to two heads.
What is the notochord?
Created by cells migrating anteriorly from the primitive node. has inductive effects on surrounding tissues.
What is neurulation?
Take place around the 3rd week. Its when the notochord signals the ectoderm to thicken and become neural ectoderm. This neural plate develops a flap and grooves that eventually fold on itself and create a neural tube (CNS)
What are somites?
paired mesoderm on either side of the neural tube that develops into dermis, muscle, tendon, and bone.
What is spina bifida?
When the sacral region of the neural tube doesn’t close properly
What is anencephaly?
When the cephalic region of the neural tube doesn’t close properly
What is neural crest?
Cells that originate from the ectoderm but are important in a variety of things including formation of dentin and facial cartilage (ex. abnormal NC migration can lead to Treacher Collins Syndroms)
When is the embryo most susceptible to teratogens?
3-8 weeks when most organ systems are being established
