LECTURE 2: HISTOLOGY OF FEMALE GENITAL TRACT BY EN. MOHD NAZRI B. ABU UiTM CLINICAL CYTOLOGY ML236
A human begins life as a fertilized ovum. This single cell gives rise to the millions of cells that form the human body. In the first few days following fertilization, the developing embryo consists of a ball of cells. This implants on the wall of the uterus and begins to grow further, supported by nutrients and blood from the mother. INTRODUCTION
Embryology Simplified Fertilized -------> Cellular division, ------> Adult ovum differentiation, and growth human The three major embryologic categories of cells, called the germ cell layers, are: Ectoderm : forms the epithelium that covers the body, and gives rise to cells in the nervous system Endoderm: forms the gastrointestinal tract and associated structures involved in digestion Mesoderm : forms the connective tissues and "soft" tissues such as bone, muscle, and fat
External Female Genitalia The external genitalia, including -labia majora -labia minora -clitoris, are covered by keratinized stratified squamous epithelium. The clitoris has erectile tissue consisting of irregular endothelial-lined sinuses with intervening fibrovascular connective tissue
INTERNAL FEMALE GENITAL TRACT The female genital tract consists of the the internal genitalia with -vagina -uterus (Cervix & endometrium) -fallopian tubes -ovaries.
The vagina is a muscular tube lined by a stratified squamous mucosa containing abundant glycogen.
There is no epithelial keratin layer, but the mucosa is protected by an acid environment resulting from bacterial growth on a glycogen substrate supplied by the mucosa.
There is a connective tissue layer beneath, the lamina propria, which may contain some lymphocytes, with prominent vessels, but no glands are present.
The lower end of the vagina has a surrounding skeletal muscle
The upper vagina merges with the uterus at the cervix.
The vagina has a stratified squamous epithelium, beneath which is a vascular lamina propria without any glands.
Cervix - The cervix is the lower end of the uterus. -The outer cervix is lined by a stratified squamous mucosa containing abundant glycogen. -The underlying fibrovascular connective tissue of the lamina propria merges with smooth muscle bundles; there may be some scattered lymphocytes. -At the cervical os, the squamous epithelium changes to a tall columnar mucinous epithelium- squamocolumnar junction is called the transformation zone.
Normal cervix is seen at high power, with non-keratinizing squamous epithelium. The basal cells are seen at the right, and there is progressive maturation to the surface, where the flattened squamous cells have a low nuclear/cytoplasmic ratio with abundant pale-staining cytoplasm containing glycogen. The epithelium lies above the basement membrane. The submucosa is at the far right
cervix-On surfaces receiving greater wear and tear, there is a thick layer of acellular keratin (keratinizing squamous epithelium), as on skin .
The body of the uterus consists of a thick muscular wall surrounding the endometrial cavity, which in the non-pregnant uterus is just a slit-like cavity.
The endometrial cavity is lined by the endometrium, which is highly responsive to hormonal changes.
The actual endometrial epithelial surface of columnar cells, some of which are ciliated, is not prominent. What is prominent are glands in a thick lamina propria.
Thus, endometrium consists of glands and stroma.
The stroma is composed of many small fibroblastic cells along with scattered lymphocytes, macrophages, and blood vessels.
At low power the uterus has a superficial columnar layer of cells, seen here overlying a stratum basalis layer with developing proliferative phase endometrium. The myometrium composed of smooth muscle bundles is below the endometrial layer which lines the central endometrial cavity of the uterus.
Each ovary contains the ova, or primordial germ cells, that contain a haploid number of chromosomes.
an ovum has a karyotype of 23, X and can be fertilized by either a 23, X or 23, Y sperm to produce a 46, XX female or 46, XY male offspring.
The fetal ovary contains mostly ova, with an indistinct intervening stroma.
Beginning and late gestation and throughout childhood, ova disappear, until at the time of reproductive maturity at menarche, less than a couple of hundred ova remain in each ovary which can be released during each menstrual cycle throughout
Normal adult ovary at low magnification reveals a dense ovarian cortex with abundant stroma and few follicles. A developing follicle is near the center. At the lower right is a pink cloud-like corpus albicans