Anatomy and Physiology - Essay 2

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  • Topic: Uterus, Cervix, Ovulation
  • Pages : 2 (1679 words )
  • Download(s) : 57
  • Published : April 23, 2012
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ANATOMY AND PHYSIOLOGY 

The vagina is a thin-walled tube 8 to 10 cm long. It lies between the bladder and rectumand extends from the cervix to the body exterior. Often called the birth canal, the vagina providesa passageway for the delivery of an infant and for the menstrual flow to leave the body.The cervix (from Latin "neck") is the lower, narrow portion of the uterus where it joinswith the top end of the vagina. Where they join together forms an almost 90 degree curve. It iscylindrical or conical in shape and protrudes through the upper anterior vaginal wall.Approximately half its length is visible with appropriate medical equipment; the remainder liesabove the vagina beyond view. It is occasionally called "cervix uteri", or "neck of the uterus".During menstruation, the cervix stretches open slightly to allow the endometrium to beshed. This stretching is believed to be part of the cramping pain that many women experience.Evidence for this is given by the fact that some women's cramps subside or disappear after their first vaginal birth because the cervical opening has widened.

 
The portion projecting into the vagina is referred to as the portio vaginalis or ectocervix.On average, the ectocervix is three cm long and two and a half cm wide. It has a convex,elliptical surface and is divided into anterior and posterior lips. The ectocervix's opening is calledthe external os. The size and shape of the external os and the ectocervix varies widely with age,hormonal state, and whether the woman has had a vaginal birth. In women who have not had avaginal birth the external os appears as a small, circular opening. In women who have had avaginal birth, the ectocervix appears bulkier and the external os appears wider, more slit-like andgaping.The passageway between the external os and the uterine cavity is referred to as theendocervical canal. It varies widely in length and width, along with the cervix overall. Flattenedanterior to posterior, the...
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