Ovarian Structure and Function Quiz

Female Reproductive System

• The female reproductive system includes ovaries, uterine tubes (oviducts), uterus, cervix, vagina, vestibule, vulva, and associated glands. It's involved in ova production, fertilization, and pregnancy accommodation.
• Objectives include recalling and naming organs, identifying associated structures histologically, comparing organs across species (mammalian and avian), and relating structures to their functions.

Organs and Functions

• Ovaries: Responsible for female gamete (ova) development and maturation. They also act as endocrine glands secreting hormones like estrogen, progesterone, testosterone, and androgens. A corpus luteum forms in the ovary during certain stages of the reproductive cycle and pregnancy, producing hormones. In some species, the shape of ovaries can vary (e.g., bean-shaped in mares).
• Uterine Tubes: Transport ova and sperm (for fertilization), forming the zygote and initiating embryo development. This process occurs within the distal part of the uterine tubes.
• Uterus: Houses the developing embryo/fetus, allowing its implantation and nurturing development, and formation of the placenta. The uterine lining's modifications during pregnancy are species-specific.
• Cervix: Acts as a part of the birth canal. The structure and secretions of the cervix can change based on the stage of the reproductive cycle.
• Vagina, Vestibule and Vulva: Together form the birth canal and the copulatory organs. They undergo changes in structure that are noticeable in sexually mature organisms and noticeable in the ovarian parenchyma and uterine mucosa.

Ovarian Follicles

• The ovary comprises follicles in various developmental stages (primordial, primary, secondary, tertiary), impacting the reproductive cycle.
• Different follicles reflect varying stages of development and secretory activity.
• Primordial follicles are the most numerous and contain oocytes at an early stage.
• Primary follicles become evident at puberty, while more advanced follicles (secondary and tertiary) emerge as the organism matures.
• Mature follicles expand to have an antrum filled with follicular fluid which supports the oocyte to prepare for ovulation.
• Post-ovulatory follicles remain, which form the corpus luteum (in some species) to support pregnancy.

Corpus Luteum and Corpus Albicans

• The corpus luteum forms after ovulation and produces hormones vital to maintaining pregnancy (progesterone).
• If pregnancy doesn't occur, the corpus luteum regresses, often to become the corpus albicans.
• Each stage has characteristic tissue structure and function in the ovary that varies based on species.

Uterine Tubes (Oviducts)

• The fallopian tubes consist of four regions: infundibulum, ampulla, isthmus, and interstitials.
• The fimbriae, finger-like projections of the infundibulum, help guide ova into the tubes and promote transport.
• The mucosa of the tubes can have folds and, in some, have ciliated cells aiding the transit of both ovum and sperm.
• The tubes have smooth muscle structures to support the passage of cellular components and provide propulsion to the uterine cavity.

Uterus and Cervix

• The uterine wall is composed of three layers (innermost: endometrium, middle: myometrium, and outer: perimetrium) to support the developing fetus, placenta, and pregnancy.
• The cervix has a specific structure (usually with mucus-secreting glands). The cervix's structure and secretions change across the reproductive cycle, e.g., formation of cervical "plugs" during pregnancy.
• Species exhibit variations and changes in cellular and tissue types throughout the female reproductive cycle.
• The uterine wall layers exhibit distinct characteristics and functions according to the species and the stage of reproductive cycle.

Vagina

• Primarily involved in the birth canal as well as sexual intercourse, the vagina has a stratified squamous epithelium, which provides protection against abrasion.
• The vagina is structurally similar to the end of the fallopian tubes, in that it contains smooth muscle layers surrounding a non-vascular layer.
• Changes in cells and overall structure of the vagina are noticeable during the reproductive cycle, reflecting hormonal influence.
• The vaginal epithelium contains varied cell types and thicknesses depending on the species and the stage of estrus.

Cyclic Changes in the Ovary

• The ovary goes through cyclic changes. These changes are in direct correlation with proestrus, estrus, metestrus, diestrus, and anestrus stages of the estrus cycle.
• Cyclic changes influence hormonal regulation and support of the reproductive system.

Vaginal Cytology

• Vaginal cytology is a method of diagnosing the estrous stages in animals (like dogs or cats).
• A detailed study of cell types in the vagina provides information on the reproductive condition.