MICROSCOPIC STRUCTURE OF OVARIES, UTERUS, AND FALLOPIAN

TUBE.

1

Dr. Amal Abd El hafezAssociate professor of histopathology

Objectives• At the end of this practical session you will be able to

identify sections, label diagrams and discuss:• The ovarian structure. • Varying stages of follicular development leading to

ovulation or follicular atresia.• The histological characteristics of the oviducts

[Fallopian tubes= uterine tubes].• The body of a mature uterus and various layers of the

uterus.

2

The female reproductive system consists of: two ovaries, two oviducts (uterine= Fallopian tubes), the uterus including body and cervix, the vagina, and the external genitalia.

Its functions: 1-Produce female gametes (oocytes=ova)

2-Site of fertilization, hold a fertilized oocyte during its complete development through embryonic and fetal stages until birth. 3- The ovaries produce female sex hormones [estrogen and progesterone] that control organs of the reproductive system and influence other organs of the body.

INTRODUCTION

3

The Female Reproductive System 4

• Ovaries are covered by:1-Simple cuboidal germinal epithelium [misnomer, its

mesothelial derived], 2- tunica albuginea.

• the ovary is divided into:1- outer cortical region, 2- inner medullary region.3-Ovarian hilum

• Ovarian tissue is composed of:1- ovarian follicles [at different stages of development, in the

cortex], 2- ovarian stroma [spindle cells + collagen fibers].

The ovarian structure

5

The ovary

6

• consists of:1. Oocyte=ovum=egg: in the center.2. Follicle cells: surround the oocyt and include: Granulosa cells

and Theca cells [derived from ovarian stroma]• Theca & granulosa cells work together to produce hormones.

• 4 types of follicles are known:1. Primordial follicle2. Primary follicle3. Secondary follicle4. Tertiary=Graafian follicle

What are the ovarian follicles?

7

Follicle Development= Folliculogenesis

8

• The process in which a primordial follicle grows and

develops into Graafian follicle with the potential to

either ovulate its egg into the oviduct at mid-cycle or

to die by atresia.

Stages of Folliclar Development= Folliculogenesis

1. Primordial follicles: Present in ovary from birth till puberty [about half a million], oocyte surrounded by one layer of flat squamous cells.

2. Primary follicle: Start to develop after puberty, [each month 20-30 follicle] two or more layers of cuboidal granulosa cells called zona granulosa and a layer called zona pellucida surround the oocyte.

9

3. Secondary follicle: oocyte surrounded by the zona pellucida, multiple layers of granulosa cells [cumulus oophorus]+ theca cells, has a fluid-filled spaces between granulosa cells.

10

4. Graafian follicle : Bulges from the surface of the ovary. Shows the theca externa, theca interna, basal lamina, granulosa cells forms corona radiata, around the oocyte, and follicular antral fluid.

11

At ovulation: Oocyte + Zona pellucida+ corona radiataare expelled to peritoneal cavity

5. Corpus luteum : ruptured follicle after ovulation, it produces progesterone for 2 weeks [Corpus luteum of menstruation]

• If a pregnancy occurred, it continues hormone production to maintain the wall of the uterus during the early period of fetal development [Corpus luteum of pregnancy]

6. If fertilization does not occur, the corpus luteum degenerates into a mass of scar tissue called the corpus albicans.

12

13

Corpus albicans

Corpus luteum

7. Atretic follicle: WHAT? An ovarian follicle that has undergone

degeneration or involution. WHEN? Follicles at any stage of development [fetal

period, before puberty, reproductive period] may undergo atresia.

HOW? Follicle →Glassy membrane → corpus fibrosa→ disappear.

14

Uterine Tubes (Fallopian Tubes=oviduct)• Formed of interstitial part, isthmus, ampulla,

infundibulum, fimbriae.• Function: Capture ovum from ovarian surface toward

the uterus, site of fertilization.

• Histology:(1) a mucosa: folds of a simple columnar epithelium

[ciliated and secretory] and a lamina propria composed of loose connective tissue.

(2) a thick muscularis composed of smooth muscle.(3) a serosa composed of visceral peritoneum.

15

Fallopian Tube Histology16

Cilia and tubal fluid move ovum/zygote toward the uterus

• Hollow, thick-walled organ composed of: body, and cervix. The wall of the uterus is relatively thick and is composed of three layers

• Endometrium:

– Simple columnar epithelium [ciliated and secretory, some times pseudostratified ]

– Stroma of connective tissue and endometrial glands

• Stratum functionalis: Shed during menstruation.

• Stratum basalis: Replaces stratum functionalis each month.

17

The Uterus

18

• Myometrium

Interlacing bundles of smooth muscle, contain large blood vessels.

• Perimetrium

Serosa or adventitia.

Phases of the Endometrium [stages of the menstrual cycle]

Proliferative phase: from end of menstruation to 14 days of menstrual cycle under estrogen effect. Endometrial glands are straight. Cells are crowded with frequent mitoses. The stroma is dense.

19

Secretory phase (or luteal): Second 14 days of menstrual cycle under progesterone effect. Glands are tortuous [serrated, Saw-toothed] and their lumena are filled with gslycoprotein secretions. Stroma is edematous.

20

The menstrual phase: First 4-5 days of the cycle. Ischemia [due to↓ER,PR] leads to shedding of stratum functionalis.

21

ovary

ovary

uterus

uterus

Fallopian tube

Fallopian tube

RECOMMENDED REFERENCES, WEBSITES

• Junqueira's Basic Histology: Text and Atlas, Thirteenth Edition 2013

• ISBN-13: 978-0071780339 ISBN-10: 0071780335 Edition: 13th

• The histology tutor:http://www2.yvcc.edu/

histologyzoomer/HistologyTutorials/histology_tutorials.htm

28