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.
<ul><li>Vagina </li></ul><ul><li>The vagina is a muscular tube lined by a stratified squamous mucosa containing abundant glycogen. </li></ul><ul><li>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. </li></ul><ul><li>There is a connective tissue layer beneath, the lamina propria, which may contain some lymphocytes, with prominent vessels, but no glands are present. </li></ul><ul><li>The lower end of the vagina has a surrounding skeletal muscle </li></ul><ul><li>The upper vagina merges with the uterus at the cervix. </li></ul>
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 .
<ul><li>Endometrium </li></ul><ul><li>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. </li></ul><ul><li>The endometrial cavity is lined by the endometrium, which is highly responsive to hormonal changes. </li></ul><ul><li>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. </li></ul><ul><li>Thus, endometrium consists of glands and stroma. </li></ul><ul><li>The stroma is composed of many small fibroblastic cells along with scattered lymphocytes, macrophages, and blood vessels. </li></ul>
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.
<ul><li>The fallopian tube is lined by a columnar epithelium , some with cilia and some with a secretory function. </li></ul><ul><li>Some of the cilia beat upward to help sperm ascend, while other beat downward to conduct ova toward the uterus. </li></ul><ul><li>Beneath this epithelium is a lamina propria and then a muscularis of inner circular and outer longitudinal layers. </li></ul><ul><li>The structure of the fallopian tube is complex in cross-section, with many fingers of epithelial-covered lamina propria creating a maze-like appearance. There is a surrounding mesothelium. </li></ul>FALLOPIAN TUBE
Normal adult fallopian tube has ciliated columnar cells lining
<ul><li>Each ovary contains the ova, or primordial germ cells, that contain a haploid number of chromosomes. </li></ul><ul><li>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. </li></ul><ul><li>The fetal ovary contains mostly ova, with an indistinct intervening stroma. </li></ul><ul><li>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 </li></ul>Ovary
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