Cervix and Vagina

Question 1

the cervix

Answer 1

The cervix is the narrow inferior portion of the uterus, part of which projects into the vaginal canal. The lumen of the cervix is called the endocervical canal. It has constricted openings at each end:
- Internal os: opens to the main uterine lumen
- External os: opens to the vagina
The cervix is divided into an upper endocervix and endocervical canal, and a lower portion that protrudes into the vagina called the ectocervix

Question 2

ectocervix

Answer 2

The external (vaginal) surface AKA the ectocervix is covered by non-keratinized stratified squamous epithelium, while the mucosa of the endocervix is lined by tall simple columnar epithelium

Question 3

endocervix

Answer 3

The endocervix rests on a thick lamina propria, with many large, branched mucus-secreting cervical glands. This mucus lubricates the vagina and nourishes spermatozoa. The wall of the cervix consists of dense CT and smooth muscle

Question 4

progesterone and cervical mucus

Answer 4

Under the influence of progesterone, the consistency of cervical mucus changes cyclically and plays a significant role in fertilization and early pregnancy
- At ovulation, mucus secretion is abundant and watery, facilitating sperm movements into the uterus
During pregnancy, the cervical glands proliferate and secrete highly viscous mucus that forms a plug in the cervical canal, which prevents the entry of sperm and microorganisms

Question 5

the vagina

Answer 5

A fibromuscular tube extending from the cervix to the external genitalia. The vagina serves as the depository for sperm and serves as part of the birth canal at parturition
The wall of the vagina lacks glands, and is composed of three layers: mucosa, muscularis, and adventitia

Question 6

vagina mucosa

Answer 6

Consists of a non-keratinized stratified squamous epithelium, and an underlying lamina propria, which is rich in elastic fibres and contains an extensive coiled venous plexus. The mucosa does not contain glands

Question 7

vagina muscularis

Answer 7

Comprises two poorly defined smooth muscle layers:
- The inner circular layer
- The thick outer longitudinal layer that is continuous with the myometrium of the uterus
The fibres of the two layer intermingle with each other

Question 8

vagina adventitia

Answer 8

Has a dense CT layer that blends with the surrounding tissues. It contains considerable elastic tissue, extensive venous plexus, and bundles of nerves