Special Histology and Embryology: Practical Course - V. K. Napkhanyuk 2001

Reproductive System
Female Reproductive System
Vagina

The vagina is a musculo-fibrous tube, 7-9 cm long and 2-3 cm in diameter, extending within the lesser pelvis between the Urethra and the rectum.

The vaginal wall consists of three layers: mucosal, muscular, and adventitial.

The vaginal mucosa is lined with stratified squamous epithelium, which is divided into three layers: basal, intermediate, and superficial (or functional).

The superficial, or functional, layer of the vaginal mucosa undergoes significant rhythmic (cyclic) changes throughout the successive Phases of the Menstrual cycle. The Cells of the superficial layers contain keratohyalin granules rich in Glycogen. The breakdown of glycogen by microbial action leads to The production of lactic acid; consequently, vaginal mucus has an acidic reaction and bactericidal properties that prevent the proliferation of microorganisms. Glands are absent in the vaginal wall.

The lamina propria of the mucosa forms papillae that project into the epithelium and are infiltrated by lymphocytes. Elastic fibers within the lamina propria form superficial and deep networks.

The muscular layer of the vagina is formed by longitudinal bundles of smooth myocytes, interspersed with a small number of circularly arranged Muscle elements.

The adventitial layer of the vagina consists of loose irregular Connective Tissue that connects the vagina to adjacent Organs.

Slide 9. Cross-section of the human vagina (Fig. 79).

Low magnification. Examine and sketch the slide.

The vaginal wall consists of three tunics: mucosa, muscularis, and adventitia.

Mucosa: non-keratinized stratified squamous epithelium. It comprises three layers: basal, intermediate, and superficial (or functional). The lamina propria is formed by loose connective tissue, with elastic fibers forming superficial and deep networks. It contains Blood Vessels, frequently exhibiting lymphoid infiltrations.

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Fig. 79. Cross-section of the human vagina. Hematoxylin and eosin stain. x 40:

1 — mucosa (a — non-keratinized stratified squamous epithelium; b — lamina propria of the mucosa; c — blood vessels); 2 — muscular layer; 3 — connective tissue; 4 — adventitia

The muscular layer is predominantly formed by longitudinally oriented bundles of smooth muscle cells, though a small number of circularly arranged smooth muscle bundles are present in its middle portion.

The adventitia consists of loose irregular connective tissue.

Label the following on the diagram: 1) mucosa: a) stratified squamous epithelium, b) lamina propria of connective tissue (blood vessels, lymphoid infiltrations); 2) muscular layer: a) smooth muscle bundles; b) blood vessels; 3) adventitia — loose irregular connective tissue (blood vessels, nerve bundles).

Electron micrograph 47. Oocyte from an ovarian follicle. x 25,000:

1 — Nucleus; 2 — nucleolus; 3 — yolk granules in the Cytoplasm; 4 — multivesicular bodies; 5 — Cell membrane (ovolemma) with microvilli; 6 — zona pellucida; 7 — follicular cells of the granulosa layer; 8 — processes of follicular cells (from Rodin's atlas)

Control Questions

1. Sources of ovarian development.

2. Structure and histophysiology of the Ovaries in an adult female.

3. Oogenesis.

4. Ovulation. Mechanisms.

5. Corpus luteum. Histophysiology.

6. Mechanism of follicular atresia.

7. Endocrine Functions of the ovaries.

8. Fallopian tubes. Development. Structure.

9. Uterus. Development. Structure.

10. Structural Features of the cervical mucosa.

11. Blood supply to the uterus.

12. Vagina. STRUCTURE OF THE vagina.

13. Sexual cycle. Ovarian-Menstrual Cycle.

14. CHARACTERISTICS OF THE postmenstrual period.

15. Characteristics of the premenstrual period.

16. Features of cyclic Changes in the vaginal mucosa.

17. Age-related changes in the FEMALE REPRODUCTIVE ORGANS.

18. Hormonal Regulation of the FEMALE Reproductive System.

19. Histological structure of the external genitalia.

20. Structure and histophysiology of the Mammary Glands.

Electron photomicrograph 48. Apical part of a ciliated epithelial cell of the oviduct mucosa. x 63,000:

1 — cytoplasm; 2 — cytolemma; 3 — cell cilia; 4 — basal bodies (kinetosomes) (after Brockman and Fredricsson)

Situational problems

1. Three human ovarian specimens were examined. The first shows primordial, primary, and numerous atretic follicles in the cortical layer. The second, In addition to the aforementioned structures, contains secondary and tertiary (mature) follicles. The third specimen shows a small number of follicles (primordial, primary, secondary), their massive atresia, and The Development of connective tissue. Which age periods are characterized by such an organ structure?

2. During an abortion, all layers of the endometrium were radically removed in a woman. What pathological condition will this lead to?

3. Histological examination of the endometrium obtained by curettage revealed the presence of A large number of strongly developed and expanded uterine glands. Which phase of the cycle does this state of the endometrium correspond to? What structural Features of the Ovary can be noted in this case? Which sex hormone is predominantly secreted during this period?

4. Remnants of the functional layer of the endometrium (glandular Regions of the fundus) were found in the uterus. Which phase of the menstrual cycle is in question?

5. On days 22–23 of the cycle, follicles of varying degrees of maturity and atretic bodies are present in the ovary. Does this organ structure correspond to the norm? Is Pregnancy possible?

6. Numerous poorly differentiated cells are found in the uterine stroma. During which stage of the menstrual cycle is this histological picture observed?

7. A Miscarriage occurred at the third month of pregnancy. The function of which ovarian structures was impaired? What are the possible causes of the miscarriage?

8. Histological analysis of an endometrial biopsy from a healthy woman reveals large, compactly arranged, polygonal cells rich in Lipids and glycogen within the stroma. What cells are these? During which period of the menstrual cycle was the biopsy taken?

9. A parturient woman exhibits weak labor activity caused by poor myometrial contractility. Which hormonal agents should be administered in this case?

Sample Examination Questions

1. Ovary. Structure, oogenesis, and endocrine function. Cyclic changes during Puberty and their hormonal regulation. Age-related changes.

2. Uterus, uterine tubes, vagina. Structural and functional characteristics. Cyclic changes and their regulation. Age-related features.