Female Repro System 2 Flashcards
Let’s talk uterus. What are the 3 layers of tissue in this fine fine organ?
From the outside in:
- Perimetrium: connective tissue
- Myometrium: highly vascular smooth muscle
- Endometrium: simple columnar epithelium
What happens to the myometrium during pregnancy?
It undergoes hypertrophy and hyperplasia so it can push baby out during birth
Th endometrium has two layers. Tell me about them.
- Basal layer: next to the myometrium, highly cellular lamina propria and the basal end of the myometrial glands. This layer stays the same in the menstrual cycle.
- Functional layer: superficial layer with spongier lamina propria and including most of the length of the myometrial glands. This layer changes during the menstrual cycle.
Describe the blood supply to the endometrium.
Arcutate arteries from the myometrium give off two smaller arteries to the endometrium
- Straight arteries: supply basal layer
- Spiral arteries: progesterone sensitive long arteries that supply the functional layer
IN THE UTERUS, we talk about 3 phases of the menstrual cycle. What are they?
- Menstrual phase
- Proliferative phase
- Secretory phase
Whats the significance of the menstrual phase (REAL TOUGH ONE GUYS)
Menstrual phase: you got it, the shedding of the endometrial lining and microvasculature. Occurs when fertilization doesn’t happen and the corpus luteum regresses, so there is less progesterone and estrogens. No progesterone causes
- arterial muscle contractions that disrupt blood supply to the functional layer
- more prostaglandin production causing vasoconstriction and hypoxia
What is the significance of the proliferative phase (maybe something to do with proliferation but what do I know)
Proliferative phase: ovarian follicles start to grow, and eventually develop theca cells that make and secrete estrogen. Estrogen causes regeneration of the functional layer with its microvasculature and glands.
Annnd finally the secretory phase of the menstrual cycle.
Secretory phase: Corpus luteum secretes progesterone that causes the uterine glands to secrete glycogen (for potential embryo), which dilates the lumen. Endometrium reaches max thickness (5mm). Progesterone also inhibits myometrial contraction that would interfere with embryo implantation.
So now we have fertilization, what’s going on with the zygote? As it approaches the uterus to implant, what kind of changes does it undergo?
The zygote undergoes mitotic divisions of cells called blastomeres in a compact ball called the morula. During these divisions, the cells are getting smaller, and the morula stays the same size.
At around 5 day post fertilization, the morula is now called the _____________
Blastocyst
Before implantation occurs, the cells of the blastocyst change and split into two layers. What are they?
- Trophoblasts: peripheral layer
2. Embryoblast: inner cell mass
Implantation! How does this process happen?
Lasts about 3 days. The trophoblasts help drive this process, differentiating into the cytotrophoblasts and the syncytiotrophoblast cells. The embryoblast cells differentiate into the amnion and the yolk sac.
What do cytotrophoblasts do?
They surround the amnion and yolk sac. They are mitotically active cells that eventually produce anti-inflammatory cytokines to protect against uterine reaction to the implanted embryo.
What do syncytiotrophoblasts do?
These are non mitotic cells that are made of multinucleated cytoplasm that invades the stroma of the uterus.
Now that we have implantation, the whole endometrium is now called the _________ and it is split into 3 layers: ____________, _____________ and ______________
- Decidual cells
- Decidua basalis: develops chorionic villi that eventually make up the placenta.
- Decidua capsularis
- Decidua parietalis