Early conceptus growth and immunobiologic adaptations of pregnancy Flashcards
Type 2 CD4+ Th cells (Th2) produce …
IL-4
Type 1 CD4+ Th cells (Th1) control …
Cell-Mediated Responses.
The placenta can release factors that suppress …
T-cell and NK-cell activity.
HLA-G serves a dual role in protecting the trophoblast
from both …
Cytotoxic T cells and NK-cells.
First-trimester pregnancy decidua is composed
predominantly of …
Immune cells.
(Approximately, 10% of the stromal cells are T lymphocytes, 20% are macrophages, and the main immune cell population is large granular lymphocytes or NK cells, comprising 45% of the decidual cells).
The adherence of the blastocyst to the endometrial
epithelium is mediated through ..
ligand-receptor complexes.
Three cytokines appear to be involved in implantation …
Colony-stimulating factor 1;
Leukemia inhibitory factor;
Interleukin 1.
Human Chorionic Gonadotrophin is essential in
stimulating …
the corpus luteum to produce progesterone.
The cortical and zona reactions are triggered after …
egg–sperm fusion.
Prior to sperm–egg interaction …
capacitation of the spermatozoa must occur.
During meiosis, the primary oocyte gives rise to four daugther cells, each receiving 22 autosomes and an X chromosome.
The primary spermatocyte also gives rise to four daughter cells, each receiving 22 autosomes and either an X or a Y chromosome.
Capacitation is characterized by …
the acrosome reaction, the ability to bind to the zona pellucida, and the acquisition of hypermobility.
The zona pellucida (ZP) is an acellular glycoprotein coat covering the ovum and consists of three principal
proteins:
ZP1, ZP2 and ZP3.
Upon Fusion of the egg and sperm membranes …
The cortical and zona reactions are triggered.
After egg-sperm fusion …
The oocyte will resume the second meiotic division and extrude the second polar body.
The morula enters the uterus 3 days after fertilization and floats inside the endometrial cavity for 2-3 days. The embryo begins implantation approximately …
6 days after fertilization.
Gametogenesis
Is the maturational process that produces specialozed gametes.
Specialized Gametes
- Spermatozoon (in the male);
- Oocyte (in the female).
Fertilization
The union of individual male and female gametes.
Consists of a regulated sequence of interactions that will ultimately result in embryo development
Proposed sequence for mammalian gamete interaction:
- Completion of capacitation in the oviductal isthmus;
- Admission into and through the cumulus matrix;
- Primary binding to ZP3 on the sperm plasma membrane;
- Triggering of acrossomal exocytosis;
- Secondary binding to ZP2 using components exposed after the acrossomal reaction;
- Autoactivation of proacrosin to acrosin, with attendant digestion through the ZP matrix;
- Binding, followed by fusion between sperm ans egg plasma membranes.
There is fusion of the sperm and egg membranes with specific proteins mediating this process. One such fusion protein is …
Fertilin.
What proteins prevent further sperm binding on the oolema?
ZP2 and ZP3, turning the oolema impenetrable to spermatozoa.
How much blastomeres the morula is composed of …
12-16 blastomeres.
When the blastocyst forms …
When approximately 60 blastomeres are present.
The developing embryo essentially does not increase in size until …
The zona pellucida is shed.
IL-4 stimulates …
IgE and IgG antibody production by Bcells (Th2 response).
Type 1 CD4+ Th cells (Th1) secreat what cytokines …
IL-2; TFN-beta; IFN-Gama;
which stimulate cytotoxic T cells and NK cells
Is there more suppression of immune function during
pregnancy?
There is no clear trend toward either the enhancent or the supperssion of immune function during pregnancy.
In the placenta, class I antigen expression occurs in the mesenchyme of the chorionic villi as early as …
2.5 weeks.
In the placenta, class II antigen expression occurs in the mesenchyme of the chorionic villi by …
14 weeks’ gestation.
HLA-G inhibits and decrease …
- Inhibits the proliferation of CD4+ T lymphocytes;
- Decreases decidual cell production of IFN-gama and TNF-alfa;
What fetal cells can enter the maternal blood in early pregnancy?
Fetal nucleated erythrocytes and leukocytes
The primitive endoderm arises from …
The Hypoblast.
The mesoderm and the ectoderm developes from …
The epiblast.
The primitive germ layers develop between …
Days 6 and 8.
The embryo is completely imbedded within the endometrium by …
Approximately 8-9 days afrer fertilization.
The trophoblast differentiates into two layers consisting of
Inner cytotrophoblast and an outer syncytiotrophoblast.
The trophoblast differentiates into two layers consisting of
Inner cytotrophoblast and an outer syncytiotrophoblast.
When the blastocyst superficially implants in the stratum compactum of the endometrium by?!
The end of the first week.
When the blastocyst superficially implants in the stratum compactum of the endometrium by?!
The end of the first week.
Two areas of contact between mother and fetus are established
1- A large surface area formed by syncytiotrophoblast of the chorionic villi that is bathed by maternal blood;
2- Within the deciduas, extravillous trophoblast that mingles directly with maternal tissues.
Two areas of contact between mother and fetus are established
1- A large surface area formed by syncytiotrophoblast of the chorionic villi that is bathed by maternal blood;
2- Within the deciduas, extravillous trophoblast that mingles directly with maternal tissues.
The interface between mother and fetus is extensed by
The traffic of fetal cells into the maternal circulation, carrying fetal antigens to other parts of maternal immune system, where priming responses could also occur
There are two aways in which might happen the process in which the trophoblast cells enter the maternal circulation:
1- Trophoblast “buds” (called syncytial sprouts) often form on the syncytiotrophoblast surface and may break free and enter the maternal blood.
2- The endovascular cytotrophoblast that lines the spiral arteries may be carried away into the bloodstream.
The tissue in which immune recognition of trophoblast is most like to occur
The decidua.
Polyclonal antibody studies have confirmed that HLA-G protein is expressed only by
Extravillous cytotrophoblast
