Cervix | Parts of Cervix скачать в хорошем качестве

Cervix | Parts of Cervix

#gynecology #femalegenitalia #cervix #uterus #pregnancy #womb #obstetricsandgynecology #anatomyofuterus CERVIX: The cervix is composed mainly of fibrous connective tissues. The smooth muscle fibers average 10–15%. Only the posterior surface has got peritoneal coat. Epithelial Lining of the cervix Endocervical canal and glands There is a median ridge on both the anterior and posterior surface of the canal from which transverse folds radiate. This arrangement is called arbor vitae uteri. The canal is lined by single layer of tall columnar epithelium with basal nuclei. Those placed over the top of the folds are ciliated. There are patches of cubical basal or reserve cells underneath the columnar epithelium. These cells may undergo squamous metaplasia or may replace the superficial cells. The glands which dip into the stroma are of complex racemose type and are lined by secretory columnar epithelium. There is no stroma unlike the corpus and the lining epithelium rests on a thin basement membrane. The change in the epithelium and the glands during menstrual cycle and pregnancy are not so much as those in the endometrium. Portio vaginalis It is covered by stratified squamous epithelium and extends right up to the external os where there is abrupt change to columnar type. It is covered by stratified squamous epithelium and extends right up to the external os where there is abrupt change to columnar type. The transitional zone (transformation zone) may be of 1–10 mm width with variable histological features. The zone consists of endocervical stroma and glands covered by squamous epithelium. The zone is not static but changes with hormone level of estrogen. The site is constantly irritated not only by hormones but also by infection and trauma. Thus, there is more chance of severe dysplasia, carcinoma Secretion: The endometrial secretion is scanty and watery. The physical and chemical properties of the cervical secretion change with menstrual cycles and with pregnancy. The cervical glands secrete an alkaline mucus with pH 7.8. The mucus is rich in fructose, glycoprotein and mucopolysaccharides. It also contains sodium chloride. The fructose has got nutritive function to the spermatozoa. Under estrogenic stimulation, glycoprotein network is arranged parallel to each other thus facilitating sperm ascent. Progesterone produces interlacing bridges thereby preventing sperm penetration. Cervical mucus contributes significantly to the normal vaginal discharge. A part forms the mucus plug which functionally closes the cervical canal and has got bacteriolytic property. in situ or even invasive carcinoma at this zone