paksusuolenperäaukon

Paksusuolenperäaukon refers to the terminal part of the large intestine that terminates at the anus. This anatomical region comprises the rectum and the anal canal. The rectum is the final section of the large intestine, storing feces before defecation. It measures approximately 12 to 15 centimeters in length in adults. The rectum's primary function is to act as a reservoir for waste material, gradually filling and signaling the need to defecate.

Following the rectum is the anal canal, the shortest segment, measuring about 4 centimeters. This canal is lined with specialized tissue and contains internal and external sphincter muscles. These sphincters control the voluntary and involuntary release of feces. The internal sphincter is composed of smooth muscle and is under autonomic control, while the external sphincter is skeletal muscle and can be consciously controlled.

The process of defecation involves the coordinated action of the rectum, anal canal, and pelvic floor muscles. When the rectum is sufficiently filled, stretch receptors send signals to the brain, prompting the urge to defecate. Relaxation of the external anal sphincter and contractions of the abdominal muscles facilitate the expulsion of feces through the anal opening. Any disruption to this intricate system can lead to various functional disorders.