Unit III - The Digestive, Urinary, and Reproductive Systems

Function of the Digestive System

Breaks down food into absorbable nutrients to fuel the body and eliminates indigestible waste, specifically…

• Ingestion

• Propulsion

• Mechanical Breakdown

• Chemical Digestion

• Absorption

• Defecation

Organs of the Alimentary Canal

• Mouth

• Pharynx

• Esophagus

• Stomach

• Small Intestine

• Large Intestine

Accessory Digestive Organs

• Teeth

• Tongue

• Salivary Glands

• Liver

• Gallbladder

• Pancreas

The Peritoneum

• Location: lines the walls of the abdominopelvic cavity

• Functions:

  • Lubricates abdominal organs

  • Supports and suspends abdominal organs

Tissue Composition of Mucosa

• Epithelium

• Areolar Connective Tissue

• Smooth Muscle

Function of Mucosa

• Secretion

• Nutrient Absorption

• Barrier Protection

Tissue Composition of Submucosa

• Areolar Connective Tissue

• Dense Irregular Connective Tissue

• Blood Vessels / Lymph Vessels

• Nerve Fibers

Function of Submucosa

• Nourishment

• Elasticity

• Local Neural Signaling

Tissue Composition of Muscularis Externa

• Smooth Muscle

Function of Muscularis Externa

• Segmentation

• Peristalsis

Tissue Composition of Serosa

• Areolar Connective Tissue

• Simple Squamous Epithelium

Function of Serosa

• Lubrication

• Friction

• Reduction

• Anchoring

Stimuli of Digestive Activity

• Distension of the Abdomen

• Changes in Osmolarity

• Changes in pH

• Chemical Changes

Controls of Digestive Activity