Overview : The vulva is a part of the female reproductive system and is also part of the external genitalia. The vulva consists of labia minora, labia majora, mons pubis, clitoris, vestibular bulb, vulval vestibule, urinary meatus the vaginal opening, hymen, and Bartholin's glands. other parts of the vulva include sebaceous glands, urogenital triangle, and pudendal cleft. Pelvic floor muscles support the structures of the vulva and vulva including the entrance to the vagina. Vulva goes through changes during childhood, puberty, menopause, and post-menopause. Structure: A) Mons pubis: it is present in both sexes and act as a cushion during sexual intercourse and is more pronounced in female. the mons pubis is a soft fatty tissue at the front of the vulva in the pubic region covering the pubic bone. the lower part of the mons pubis is divided by a fissure called pudendal cleft. it separates mons pubis and labia majora, the mons pubis, and labia majora get covered by pubic hair at pu...
OVERVIEW :
The rectum is the last part of the large intestine and is placed between the sigmoid colon above and the anal canal below. Ironically the name comes from Latin rectum intestinal which means a straight line, but the rectum is not curved and is actually curved in front to back direction and also inside to side direction. Distension of the rectum causes the desire to defecate.
LOCATION AND EXTENT :
The rectum is located in the posterior part of the pelvis right in front of the sacrum and coccyx. The rectum begins as a continuation of the sigmoid colon at the level of the 3rd sacral vertebra. The rectum ends by becoming continuous with the anal canal at the anorectal region. The anorectal junction lies 2-3 cm in front and a little below the tip of the coccyx.
DIMENSIONS :
In humans the rectum is 12 cm long, in the upper part, it has the same diameter of 4 cm as of sigmoid colon but in the lower part, it is dilated to form rectal ampulla.
COURSE AND DIRECTION :
Rectum first runs downwards and backward, then downwards and finally downwards and forwards.
The rectum shows two types of curvatures in its course -
A) Anteropoaterior curves: two in number as follows -
1) The sacral flexure
2) the perineal flexure
B) Lateral curves: three in number -
1) The upper lateral curve
2) The middle lateral curve
3) The lower lateral curve
SUPPORTS OF THE RECTUM :
The rectum is supported by the following structures -
A) Pelvic floor
B) Fascia of waldeyer
C) Lateral ligaments of the rectum
D) The pelvic peritoneum
E) Perineal body with its muscles.
BLOOD SUPPLY:
The main arteries supplying the rectum are as follows:
A) Superior rectal arteries - is a continuation of the inferior mesenteric artery and supplies coats of the rectum.
B) Middle rectal artery - arises from the anterior division of the internal iliac artery and supplies the superficial coats of the lower rectum.
C) Median sacral artery - small branches arising from the back of the aorta and supplies the posterior wall of the anorectal junction.
FUNCTION:
The rectum acts as the temporary storage site for the feces. The rectum receives the fecal material from the large intestine transmitted through regular muscle contractions called peristalsis. As the rectal wall expands due to materials filling it from within stretch receptors from the nervous system located in the stimulate the desire to pass the feces, a process called defecation.
The urge to voluntarily defecate occurs after the rectal pressure increases to beyond 18mm hg and reflex expulsion at 55mm Hg.
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