Structure and Function of the Small Intestine

Small Intestine

Tube about 1" diameter, 22' long.

Alimentary Canal

Digestive tract from mouth to anus.

Duodenum

First section of Small Intestine, food breakdown.

Jejunum

Middle section, primarily absorbs nutrients.

Ileum

Final section, absorbs remaining nutrients.

Intestinal Villi

Projections increasing surface area for absorption.

Simple Columnar Epithelium

Tissue covering Villi, facilitates nutrient passage.

Blood Capillary

Carries simple sugars and amino acids.

Lacteal

Lymph capillary transporting fatty acids and glycerol.

Peristalsis

Muscular contractions moving food through intestines.

Ileocecal Valve

Sphincter controlling flow to Large Intestine.

Pancreas Secretions

Digestive enzymes aiding in food breakdown.

Liver Secretions

Bile aiding in fat digestion.

Nutrient Absorption

Process of taking in essential molecules.

Mucous Membrane

Lines intestines, secretes digestive enzymes.

Chyme

Partially digested food moving through intestines.

Electrolytes

Minerals absorbed in the Small Intestine.

Water Absorption

Process of reclaiming water from digested material.

Intestinal Glands

Secrete fluids for nutrient absorption.