Rectum

The rectum is the final straight portion of the large intestine in humans and some other mammals, connecting the sigmoid colon to the anus. It acts as a temporary storage site for feces before elimination through defecation. The rectum is typically about 10-15 centimeters (4-6 inches) long.

The walls of the rectum are muscular and capable of expanding to accommodate increasing volumes of fecal matter. Nerve endings in the rectal wall are sensitive to distension, triggering the urge to defecate. This urge can be consciously suppressed, delaying defecation.

The rectum plays a crucial role in maintaining continence, the ability to control bowel movements. Problems with rectal function can lead to conditions such as fecal incontinence or constipation.

The rectum is susceptible to various diseases and conditions, including:

• Hemorrhoids: Swollen veins in the rectum and anus.
• Anal fissures: Small tears in the lining of the anus.
• Rectal prolapse: When the rectum protrudes through the anus.
• Rectal cancer: Cancer that develops in the lining of the rectum.
• Proctitis: Inflammation of the lining of the rectum.

Diagnosis of rectal conditions may involve physical examination, sigmoidoscopy, colonoscopy, or imaging studies. Treatment options vary depending on the specific condition and may include medication, lifestyle changes, or surgery.