Rectum

• Anal canal - lined with skin that contains no hair or sebaceous gland but does contain many somatic sensory nerves, making it susceptible to pain stimuli
• External sphincter - composed of SKELETAL MUSCLE and is under VOLUNTARY CONTROL
• Internal sphincter - composed of SMOOTH MUSCLE and is under INVOLUNTARY CONTROL by the autonomic nervous system
• Intersphincteric groove - divide the two sphincter
• Anorectal joint - divides point of the anal canal and rectum
• Rectum - the lowest portion of the large intestine and is approximately 12 cm long, extending from the end of the sigmoid colon to the anorectal joint