Human Digestive System Flashcards
Major and Accessory Organs
Mouth/Oral Cavity
Entrance to system; food is moistened and chewed; polysaccharide digestion start
Pharynx
Entrance to tubular part of system (and to respiratory system); moves food forward by contracting sequentially
Salivary Glands (accessory organ)
Glands (three main pairs, many minor ones) that secrete salvia, a fluid with polysaccharide-digesting enzymes, buffers, and mucus (which moistens food and lubricates it)
Esophagus
Muscular, saliva-moistened tube that moves food from pharynx to stomach
Stomach
Muscular sac; stretches to store food taken in faster than can be processed; gastric fluid mixes with food and kills many pathogens; protein digestion starts. Secretes ghrelin, an appetite stimulator
Liver (accessory organ)
Secretes bile (for emulsifying fat); roles in carbohydrate, fat, and protein metabolism
Small Intestine
Duodenum (C-shaped, 10 inches long) receives secretions from liver, gallbladder, and pancreas.
Jejunum (3 feet long) is where most nutrients and digested and absorbed.
Ileum (6-7 feet long) is where some nutrients are absorbed, delivers unabsorbed material to large intestine
Gallbladder (accessory organ)
Stores and concentrates bile that the liver secretes
Large Intestine (colon)
Concentrates and stores undigested matter by absorbing mineral ions, water; about 5 feet long. Divided into ascending, transverse, and descending portions
Pancreas (accessory organ)
Secretes enzymes that break down all major food molecules; secretes buffers against HCl from the stomach. Secretes insulin, a hormonal control of glucose metabolism
Rectum
Distension stimulates expulsion of feces
Anus
End of system; terminal opening through which feces
Gastrointestinal tract
Starts at the stomach and extends to the tube’s terminal opening
