The organs of the digestive system are divided into two main groups:
These are the hollow organs through which food passes, is digested, absorbed, and eventually eliminated.
Connects the mouth to the esophagus.
Involved in swallowing (deglutition).
A muscular tube that transports food from the pharynx to the stomach via peristalsis (wave-like contractions).
Stomach
A muscular sac that mixes food with gastric juice (acid and enzymes).
Begins protein digestion with pepsin.
Converts food into chyme (a semi-liquid mixture).
Small Intestine
Main site of digestion and nutrient absorption.
Divided into three parts:
Duodenum – receives bile and pancreatic enzymes.
Jejunum – major site for absorption of nutrients.
Ileum – absorbs remaining nutrients and bile salts.
Large Intestine (Colon)
Absorbs water and electrolytes.
Forms and stores feces.
Includes: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.
Rectum and Anus
Rectum stores feces.
The anus controls the elimination of feces through internal and external sphincters.
These organs assist in digestion but food does not pass through them.
Salivary Glands
Secrete saliva containing amylase to start starch digestion.
Major glands: parotid, submandibular, sublingual.
Liver
Produces bile, which helps emulsify fats.
Processes nutrients absorbed from the intestine.
Gallbladder
Stores and concentrates bile and releases it into the duodenum.
Pancreas
Secretes digestive enzymes (for carbohydrates, proteins, and fats) and bicarbonate to neutralize stomach acid.