Biology Facts Practice 12: The Human Digestive System

Incisor

Chisel shaped. Used for biting off pieces of food.

Canine

Also called "cuspid". Used for holding and tearing food.

Premolar

Also called "bicuspid". Used for grinding food.

Molar

The third set is also called "wisdom teeth". Used for grinding food.

Mouth

Digestion begins here.

Esophagus

Food enters the stomach through this muscle-lined tube.

Stomach

Serves as temporary storage for food, and continues the digestion process.

Pyloric sphincter

A powerful muscle that serves as a valve to control food transfer between the stomach and duodenum.

Gastric canal

Passageway for food inside the stomach.

Gastric folds

Give inner stomach its characteristic shape.

Duodenum

c-shaped section of small intestine where bile and pancreatic ducts enter

Jejunum

Contains the longest villi of any part of small intestine, which increases surface area for nutrient absorption.

Ileum

Remaining nutrients are absorbed here before entering the cecum at the base of the large intestine.

Ascending colon

Section of the large intestine where most fluids are absorbed for recycling.

Transverse colon

The middle section of the large intestine.

Descending colon

Section of large intestine where wastes are compacted and bound together.

Sigmoid colon

S-shaped curvature of colon near the pelvis.

Rectum

Temporary storage of solid wastes.

Mesentery

Web-like structure supporting the intestines and the blood vessels traveling to and from them.

Omentum

Fatty membrane containing lymph vessels and lymph nodes that may prevent infections in the abdominal cavity.

Liver

This organ cleanses the blood and processes nutritional molecules, distributing them to the tissues.

Gall bladder

Stores excess bile, a chemical used in digesting fats.

Pancreas

This organ secretes digestive enzymes and bicarbonate, a substance used to neutralize stomach acid entering the duodenum

Spleen

This organ filters the blood, produces some white blood cells, and destroys worn out red blood cells.

Appendix

The function of this worm-shaped organ is poorly understood.

Portal vein

Blood enters the liver from the stomach, intestines, spleen and pancreas through this blood vessel.

Inferior vena cava

Blood exits the liver on its way to the heart through this blood vessel.