Histology-Female Reproductive System

Question 1

What structures are indicated in the image below?

Answer 1

What structures are indicated in the image below? T= tunica albuguinea connective tissue. F = follicles in cortex. M = medulla with lots of blood vessels and cells that make estrogen and progesterone.

Question 2

What cells are the origin of the majority of ovarian cancers?

Answer 2

Surface epithelial cells account for 70% of all ovarian tumors and 90% of malignant ovarian tumors.

Question 3

What cells are indicated below?

Answer 3

Surface epithelial (germinal epithelium) layers of the ovary. Note the simple cuboidal epithelium lying on top of the tunica albuginea connective tissue. Finally, you know you are in the ovary because you see follicles at all stages of development embedded in a stroma (note the dying follicle indicated by the black arrow).

Question 4

How do follicles form during embryogenesis?

Answer 4

Primordial germ cells migrate from the yolk sac to the genital ridge in the embryo. The mesodermal cells from the genital ridge divide and surround the germ cells. This forms follicles.

Question 5

Oocyte stem cells, what are they doing around 4 months gestation?

Answer 5

Oogonia. They divide by mitosis and form germ cell clusters, bridges and sync up to the same stage of mitosis.

Question 6

What is happening to the female germ cells around the 7th month of gestation?

Answer 6

Oogonia stem cells have entered meiosis and become an oocyte. At this point they are surrounded by follicular cells.

Question 7

What is happening to the female germ cells around birth?

Answer 7

Nothing, they are in dictyotene stage (arrested in metaphase I of meiosis I). If the oocyte is not in a primordial follicle at birth, it dies. Early in life the pool of oocytes in the ovary is fixed.

Question 8

What makes up a follicle?

Answer 8

Oocyte + surrounding follicular cells.

Question 9

When do the majority of oocytes die? Why do we lose so many between birth and puberty?

Answer 9

In utero. Also note that you decrease from 700,000 follicles at birth to 400,000 at puberty because primordial follicles are continually recruited for growth, but die due to lack of FSH secretion.

Question 10

What is responsible for the different maturity levels of follicles shown in the ovarian cortex below?

Answer 10

Kisspeptin release from the hypothalamus stimulates GnRH secretion to initiate puberty. FSH is released and stimulates follicles to mature into a Graafian follicle. One follicle will have lots of FSH receptors, grow to a large size, secrete lots of estrogen and feedback inhibit FSH release from the pituitary. This causes atresia of the other follicles.

Question 11

What follicles are you responsible for knowing?

Answer 11

Primordial follicle -> Growing follicle -> Vesicular follicle -> Mature (Graffian follicle)

Question 12

What type of follicle is this?

Answer 12

Note the oocyte in the center and simple squamous covering. This is a primordial follicle and is quiescent until it gets hormonal signaling to divide.

Question 13

What type of follicle is this?

Answer 13

Note the taller epithelial cells and increasing layers of granulosa cells (follicular epithelium). This indicates a growing follicle.

Question 14

How do oocytes communicate with the follicle cells surrounding it?

Answer 14

There are gap junctions

Question 15

What do glycoproteins form around the oocyte in the growing ovarian follicle? What cells transport oxygen and nutrients from the basement membrane of the oocyte and through the zona pellucida?

Answer 15

Zona pellucida = glycoprotein layer that induces acrosome reaction. Granulosa layer: rests on BM and transports nutrients to oocyte through zona pellucida, note that these also secrete estrogen.

Question 16

How does the oocyte of a growing follicle differ from that of a primordial follicle?

Answer 16

The growing follicle is larger, has a thicker zona pellucida and the granulosa layer (follicular layer) is more organized.

Question 17

What structures pierce the zona pellucida?

Answer 17

Oocyte cytoplasm and follicular cell cytoplasm. They communicate via gap junctions.

Question 18

Other names for a vesicular follicle?

Answer 18

Secondary or antral follicle

Question 19

What type of follicle is shown below?

Answer 19

Note that the fluid secreted by the granulosa cells forms and empty space (antrum). Also note the theca interna and theca externa. This is a vesicular ovarian follicle.

Question 20

What substance secreted by the granulosa cells is key in maintaining the quiescent status of an oocyte?

Answer 20

Oocyte maturation inhibitor, it is contained within the antrum.

Question 21

What substance is secreted by the theca interna?

Answer 21

Androgen. It is converted to estrogen by the aromatase of the granulosa cells.

Question 22

What type of follicle is indicated in the image below?

Answer 22

Note that all of the antra have coalesced to from one giant antrum. Note that mural granulosa cells are covering the wall of the follicle and cumulus oophorus granulosa cells are covering the wall of the oocyte, forming the corona radiata. This is a mature/Graafian follicle.

Question 23

What interchange is going on between the cumulus oophorus and the mural granulosa cells?

Answer 23

Mural granulosa cells are producing the oocyte maturation inhibitor and the cumuli oophorus have the receptors for the inhibiting factor.

Question 24

What structures are indicated in the image below from an ovarian ultrasound?

Answer 24

This is a Graafian follicle: 1) Ovarian tissue 2) Follicle about to rupture 3) Remains of pedicle 4) Follicular diameter > 10mm.

Question 25

What structures are indicated in the image below?

Answer 25

1) Uterine tube 2) Fimbriae 3) Ovary 4) Follicle 5) Stigma

Question 26

400,000 oocytes remain in ovaries at puberty, but only 400 are ovulated in lifetime, what happens to all the others that aren’t ovulated?

Answer 26

Most of the others die by atresia and apoptosis.

Question 27

What pushes the oocyte through ovulation?

Answer 27

A surge of LH and FSH induces an increase in volume and pressure of the follicular fluid, enzymatic proteolysis of follicular wall/stroma, deposition of glycosaminoglycans between the oocyte-cumulus complex and granulosa cells and prostaglandins trigger contraction of smooth muscle fibers in the theca externa. Note that at this time the oocyte has completed meiosis I and entered meiosis II.

Question 28

What is left behind after ovulation?

Answer 28

Mural granulosa cells and theca interna cells. LH secretion induces follicular collapse. Blood and fibrin invade the follicular cavity. These remaining cells become the granulosa letein and theca lutein which form the corpus luteum. They begin secreting progesterone and small amounts of estrogen. Finally, a rich vascular network forms within the corpus luteum and lasts for 14 days if no implantation occurs. After 14 days it degenerates and forms the corpus albicans. Levels of estrogen/progesterone decline, the pituitary is released from negative feedback and FSH secretion begins follicular maturation again.

Question 29

What are these large, blood-filled spaces?

Answer 29

Corpa hemorrhagica. This is the very beginning of the formation of a corpus luteum.

Question 30

What hormones are responsible for the growth and proliferation of the uterus?

Answer 30

Early on = estrogen, later on = progesterone.

Question 31

What would you expect to see on a higher power image of the structure taking up the entire ovarian cortex?

Answer 31

This is the corpus luteum. You would see the granulosa lutein (large cells, round nucleus, foamy cytoplasm) and surrounding theca luteal cells.

Question 32

What would you expect to see on EM of a granulosa luteal cells?

Answer 32

Lots of mitochondria w/tubular cristae, smooth ER and lipid droplets. These are all present in all cells that make steroid hormones.

Question 33

What happens to the corpus luteum on fertilization and implantation?

Answer 33

It grows in size, produces high levels of estrogen and progesterone (inhibits follicular development), steroid secretion declines after 8 weeks as placenta becomes major source of estrogen and progesterone and persists throughout pregnancy.

Question 34

What path does the egg follow after it is ovulated and where is it typically fertilized?

Answer 34

Infundibulum -\> Ampulla (site of fertilization) -\> Isthmus -\> Uterine part of oviduct

Question 35

What part of the female reproductive tract is shown below?

Answer 35

Note the mucosal infoldings on top of a lamina propria, muscularis and serosal layer. This is the fallopian tube.

Question 36

How does the uterine tube change as you get closer to the uterues?

Answer 36

Decreased mucosal infoldings, increased muscularis thickness, increased secretory epithelial cells and change in temperature.

Question 37

What cells would you likely see on higher power of this image from the oviduct?

Answer 37

Note the simple columnar epithelium. There are ciliated cells and peg cells between the ciliated cells. The peg cells secrete fluid with nutrients, factors that aid in sperm capacitation and antimicrobial factors into the uterine tube. The ciliated cells sweep the oocyte towards the uterus.

Question 38

Where are most ciliated cells found in the oviduct?

Answer 38

Infundibulum and ampulla. Note that ciliated cells increase as estrogen increases.

Question 39

What increases numbers of peg cells in the oviduct?

Answer 39

Increased progesterone secretion.

Question 40

How does the oviduct help transport the sperm up the tube?

Answer 40

Muscularis peristaltic contractions.

Question 41

How long does the conceptus remain in the uterine tube for?

Answer 41

About 4 days. At 4 days increased progesterone levels causes muscle relaxation of the isthmus so the conceptus can undergo cleavage in the uterine tube and pass to the uterus.

Question 42

Abnormal regions of implantation

Answer 42

Ovarian, tubal, intramural, abdominal and cervical pregnancies are all irregular.

Question 43

Hormonal control of the menstrual cycle

Answer 43

\*

Question 44

3 phases of the uterine menstrual cycle

Answer 44

Proliferative phase (estrogen driven), Secretory phase (progesterone driven), and Menstruation (absence of estrogen/progesterone)

Question 45

What layers of the uterus are shown below?

Answer 45

\*

Question 46

What are the layers of the endometrium?

Answer 46

Basal layer (repopulates functional layer) and functional layer (shed during menstruation).

Question 47

What is the function of the glands shown below?

Answer 47

The uterine tubular glands secrete nutrients that maximize the environment for conceptus implantation.

Question 48

How do you know this uterine section is in the proliferative phase?

Answer 48

During the proliferative phase of the menstrual cycle the epithelium reconstitutes the uterine glands lost after menses. The stromal arteries lengthen and collagen/ground substance is secreted.

Question 49

How can you tell that your are in the late proliferative phase on a histological section of the uterus?

Answer 49

The uterine tubes begin to coil.

Question 50

How can you tell you are in the secretory phase by looking at a histological section of the uterus?

Answer 50

Increased thickness from hypertrophy, edema and increased vascularity. You also see content in the widened lumen of the uterine tubes.

Question 51

What structures are indicated in the image below?

Answer 51

Spiral artery in the functional layer of the uterus.

Question 52

Why do women slough off the functional layer of the uterus as progesterone levels fall?

Answer 52

Loss of progesterone causes contraction of the spiral arteries and ischemia which causes sloughing off of the functional layer.

Question 53

How do you know you are looking at a section of a uterus that is in the menstrual phase?

Answer 53

Less edema, shrunken uterine tubules and disruption of epithelium/blood vessels and absence of epithelial cells.

Question 54

How does the myometrium grow during pregnancy?

Answer 54

Hypertrophy and hyperplasia

Question 55

What are the two components of the placenta?

Answer 55

Fetal part (formed by chorionic villus) and maternal part (derived from stratum functionalis of endometrium, becomes deciduous basal is of placenta)

Question 56

How does implantation occur?

Answer 56

The chorion (made of cytotrophoblasts with cell walls) invades the uterine wall with syncytiotrophoblasts (no cell walls) and penetrates the endometrial layer.

Question 57

What structures of the endometrium are invaded by the syncytiotrophoblasts that allows for nutrient delivery to the fetus?

Answer 57

Uterine tubes full of glycogen and blood vessels.

Question 58

How does blood flow become established to the implanting fetus?

Answer 58

Hypoxia drives proliferation of cytotrophoblasts. They infiltrate the spiral arteries and become endothelium, form in intervillous spaces. The maternal spiral arteries become large caliber low-resistance vessels that provide adequate placental perfusion.

Question 59

What goes wrong with the cytotrophoblasts in pre-ecclampsia?

Answer 59

The cytotrophoblasts don’t become endothelial cells, requiring an increase in pressure to perfuse the placenta.

Question 60

What are the different types of chorionic villi develop that house the pools of maternal blood for the embryo?

Answer 60

Primary villi: syncytiotrophoblast cells with a core cytotrophoblasts. Tertiary villi: core of mesoderm and blood vessels, this is where gas and nutrient exchange occurs between the mom and baby.

Question 61

What are the different components of the maternal placenta?

Answer 61

Decidua basilis: chorionic villi. Decidua capsularis and decidua parietalis (these fuse).

Question 62

What hormones are made by the placenta?

Answer 62

hCG, progesterone and estrogen.

Question 63

What happens when the decidua basalis is located on the inferior side of the amniotic sac?

Answer 63

Placenta previa. There is no way for the baby to get through the cervix because of the blood supply and the child must be delivered via C-section.

Question 64

Where does the needle have to go for chorionic villus sampling?

Answer 64

Decidua basalis layer where the chorionic villi are located.

Question 65

What structures are indicated in the image below?

Answer 65

1) Amniotic epithelium 2) Baby blood vessel 3) Chorionic villi 4) Intervillous space

Question 66

What makes it possible to sample maternal blood for fetal DNA?

Answer 66

Since the outside of the chorionic villi are lined by syncytiotrophoblasts, they form syncytial knots which break off and enter the mother’s circulation. These are composed of fetal DNA.

Question 67

How does the epithelium change as you approach the cervix from the vagina?

Answer 67

Stratified squamous epithelium of the vagina changes to simple cuboidal epithelium of the uterus/cervix, the cervix will also have wide glands.

Question 68

How do the secretion from these glands differ throughout the menstrual cycle?

Answer 68

Watery during menstruation, thicker mucus plug during implantation phase that prohibits sperm from messing with the conceptus.

Question 69

What is this?

Answer 69

Nabothian cervical cysts from walling off of cervical glands. Self-limiting.

Question 70

What area of the cervix is sampled in pap smears?

Answer 70

Zone of transition, it is most prone to cervical cancer.

Question 71

What are the layers of the vaginal wall?

Answer 71

Mucosal layer (avascular), muscular layer w/large blood vessels and an adventitial layer.

Question 72

What cyclic changes occur in the vaginal epithelium?

Answer 72

Estrogen promotes synthesis and accumulation of glycogen. Additionally the cells are continually desquamated.

Question 73

What antiseptic properties does the vagina have?

Answer 73

Estrogen promotes glycogen formation. Lactobacilli vaginalis promotes glycogen conversion to lactic acid and lactic acid prevents growth of many other microbes in the vagina. This is why women are more prone to yeast infection when they take antibiotics.

Question 74

What type of glands are in the mammary gland?

Answer 74

Modified apocrine sweat glands

Question 75

What makes up the architecture of the mammary gland?

Answer 75

Branched alveoli, lobes with suspensory ligaments and lots of fat.

Question 76

What cells make cholostrum and milk?

Answer 76

Cells of the alveoli

Question 77

How does the mammary gland change in menstrual cycle?

Answer 77

Cell height increases and mild accumulation within alveoli, but is still inactive

Question 78

How do you know this is an active mammary gland?

Answer 78

The secretory cells have proliferated in the acini and ducts. Note the intralobular duct (1) and interlobular duct (2). Additionally plasma cells are secreting antibodies in the milk.

Question 79

How does milk get out of the acini?

Answer 79

Contraction of myoepithelial cells (pale cells surrounding acinar cells)

Question 80

What type of duct is this?

Answer 80

Larger ducts are lactiferous ducts, note the stratified columnar epithelium.

Question 81

What is the status of this mammary gland?

Answer 81

Post-menopausal mammary gland. Many of the elements apoptose and involute due to loss of estrogen.