Large intestine (colon)

Appendix

Finger like sac attached to cecum

Rectum

Stimulates defecation reflex & holds feces

Anus

Opening through which feces are eliminated

Internal anal sphincter

Involuntary control

External anal sphincter

Voluntary control (learned when toilet trained)

Functions of large intestine

• Bacteria ferment remaining carbohydrates & proteins. They also synthesize some B vitamins and Vitamin K

• Finishes absorption of water & vitamins

• Secretes mucus to lubricate feces

• Forms & eliminates feces

Diarrhea

• Increased motility of colon & decreased water absorption by colon

• Result: frequent watery feces

• Caused by: illness, lactose intolerance, stress, food poisoning

• Can cause dehydration & electrolyte imbalances

Constipation

• Decreased motility of colon & increased water absorption by colon

• Result: infrequent, dry, hard feces that are difficult to pass

• Caused by: insufficient fiber or fluids in diet, lack of exercise, stress, waiting to defecate

• Give laxatives, fiber, drink more water, exercise

Colorectal cancer

• One of the leading causes of cancer death, even though it’s slow growing

• Begins as polyps on inside of colon; some polyps turn cancerous

• Signs & symptoms: constipation, diarrhea, abdominal pain or cramping, pencil thin stools, rectal bleeding, blood in stool

• Risk factors:

diet high in fat and low in fiber

Inflammatory bowel disease (like crohns”

Genetics

• Prevention:

High fiber, low fat diet

Regular screenings at age 30

Appendicitis

Inflammation of the appendix, can cause life threatening peritonitis if it bursts

Hemorrhoids

Varicose veins of the rectum or anus

Irritable bowel syndrome

Pain and alternating bouts of diarrhea & constipation, possibly due to stress

Inflammatory bowel disease

Inflammation of any part of the GI tract

• Crohn’s disease is one type

Cephalic phase

Brain & nerves prepare mouth & stomach for eating

Gastric phase

Nerves & hormones promote gastric secretion & motility

Intestinal phase

Nerves & hormones slow stomach emptying & promote continued digestion of food in small intestine