Pregnancy - 2/25 Lopez Flashcards
Males with what # of sperm are considered infertile?
How does estrogen aid sperm in fertilization?
Causes cervix to secrete watery mucus
Causes contractions of myometrium to hope propel sperm upward toward the oviduct
What barriers must the sperm breach during fertilization?
Expanded cumulus (corona Radiata)
ZP
PM of egg (oolemma)
At what point is it considered the end of fertilization and the beginning of embryonic development?
Mingling of chromosomes (syngamy)
What is compaction?
Cells of morula tightly bound by desmosomes and gap junctions
How does a cavity form inside the morula?
Active Transport of Na from trophoblast cells
How will the blastocyst divide?
Into outer trophoectoderm (placenta)
ICM (pluripotent)
What are pinopods?
When do they appear?
How is their development enhanced?
Inhibited?
Small, finger-like protrusions on endometrial cells
Between day 19-21
Enhanced: Progesterone
Inhibited: Estrogen
Pinopods endocytose macromolecules and uterine fluid, what does this allow?
Embryo and uterine epithelium to approximate close to one another
What does the blastocyst release that is immunosuppressive?
PAF hCG PGE2 IL-1a, IL-6 IFN-a LIF CSF Early pregnancy factor, immunosuppressive factor
What releases hCG?
What does it do?
Trophoblast of blastocyst
Sustains CL
Is an autocrine factor that promotes trophoblast growth and placental development
When is implantation initiated?
When blastocyst comes into contact with uterine wall
Roles of synctiotrophoblast? (5)
Express cadherins and integrins
Secretion of metalloproteases and other hydrolytic enzymes
Secrete hCG
Make progesterone to maintain pregnancy independently of CL
Phagocytosis and bidirectional placental transfer of gases, nutrients, and wastes
What lytic factor found in the uterine cavity are essential for the dissolution of the zona pellucida?
What is this process called?
Plasmin
Hatching
In the apposition stage of implantation, what contact is needed?
What glycoprotein May be involved in this process?
Endometrium (Decidua) and trophoblast
MUC1, expressed at apical surface of endometrial epithelium
During adhesion of implantation, the trophoblast attaches to the uterine epithelium through what?
What ligand-receptor interactions?
Microvilli of the trophoblast
Integrins
During invasion of implantation what happens to the trophoblast?
Differentiates into outer syncytiotrophoblast and inner cytotrophoblast
During invasion of implantation, what do syncytiotrophoblast protrusions secrete?
What happens next?
TNF-a and B-catenin
Penetrate the BM of uterine epithelial cells and reach the uterine stroma
Where does the blastocyst initially superficially implant?
Zona compacta
What are decidualized stromal cells derived from?
What do they maintain?
What is the endometrial stroma transformed into?
Fibroblast-like cells w/in the endometrium
Progesterone receptors
Glycogen-filled decidual cells
How is the primary chorionic villi formed?
Invading syncytiotrophoblast breaks through endometrial veins first, then arteries
Proliferation of cytotrophoblast
How is the secondary chorionic villus formed?
Mesenchymal cells from XE mesoderm invade primary villi
When is the tertiary villi formed?
Mesenchymal cells from fetal blood vessels de novo
What is the mature placenta composed of?
What is the fx unit of the placenta?
Chorionic villi, intervillous space, Decidua basalis
Chorionic villi
Where is maternal blood trapped?
How does it drain after bathing the chorionic villi?
Intervillous space
Venous orifices in the basal plate, enters larger maternal placental veins and flows into the uterine/pelvic veins
Fx of amniotic fluid?
Mechanical buffer
Fetus excretes waste through it
What mechanisms ensure adequate fetal oxygenation?
High CO/unit body weight of fetus
INC O2 carrying capacity of fetal blood
What has a higher pressure: umbilical vein or intervillous space?
Intervillous space (30-35)
How do urea and creatinine cross the placenta?
Glucose?
Passive movement from fetus to mother
FD from mother to fetus
How do lipid-soluble steroid hormones cross the placenta?
Amino acids?
Simple Diffusion
Secondary Active Transport
How do vitamins and minerals cross the placenta?
Active transport
How do LDL, transferrin, hormones (insulin), and IgG cross the placenta?
receptor mediated endocytosis - placenta takes up large molecules from the mother
What are the main hormones the placenta makes?
hCG and hPL
Antibodies are used to detect for what in suspected pregnancy?
What does this hormone bind with high affinity?
B-hCG
LH receptor