Digestion Process Overview

Digestion Process Overview

• The digestive system breaks down food into absorbable nutrients.
• Food travels through the mouth, esophagus, stomach, small intestine, and large intestine.
• Accessory organs like the liver, gallbladder, and pancreas aid in digestion.

Mouth

• Ingestion: Food enters the mouth.
• Mechanical Digestion: Teeth and tongue mechanically break down food, turning it into a bolus.
• Chemical Digestion: Saliva, containing amylase, breaks down starch into glucose.

Esophagus

• Bolus moves to the stomach through peristalsis.

Stomach

• Mechanical Digestion: Stomach muscles churn food through muscular contractions.
• Chemical Digestion:
  • Hydrochloric acid (HCl) breaks down food and activates pepsinogen.
  • Pepsin breaks down proteins into amino acids.
• Sphincters control the flow of food:
  • Cardiac/Esophageal Sphincter: Controls the entry of bolus into the stomach.
  • Pyloric Sphincter: Controls the release of chyme from the stomach.

Liver

• An accessory organ that produces bile.
• Bile aids in the mechanical digestion of fats in the small intestine.

Gallbladder

• An accessory organ connected to the liver and the small intestine.
• Stores bile produced by the liver and releases it into the small intestine.

Pancreas

• An accessory organ aiding chemical digestion.
• Secretes:
  • Bicarbonate: A base that neutralizes stomach acid going into the small intestine.
  • Trypsinogen: Activates trypsin in the small intestine, breaking down proteins.
  • Pancreatic amylase: Breaks down starch into glucose.
  • Lipase: Breaks down lipids into fatty acids.

Small Intestine

• Chemical Digestion: Begins in the duodenum and occurs with pancreatic secretions, breaking down lipids (lipase), starches (amylase), and proteins (trypsin).
• Absorption: Absorbs monomers into the bloodstream or lymphatic system.
• Increased Surface Area: Villi and microvilli on the intestinal wall increase the surface area to increase diffusion/absorption.
• Movement: Food moves along the small intestine through peristalsis.
• Regulation: Ileocecal Sphincter controls the movement of “leftovers” from the small intestine to the large intestine.

Large Intestine

• Absorption: Absorbs water into the bloodstream; not regulated.
• Egestion: Releases wastes through the rectum.
• Regulation: Rectal Sphincter controls the movement of wastes out of the large intestine.
• Gut Flora: Bacteria in the large intestine produce vitamin B and vitamin K.

This quiz tests your knowledge on the digestion process, including the roles of the mouth, esophagus, and stomach. You will explore how food is mechanically and chemically broken down into nutrients. Additionally, accessory organs like the liver and pancreas are discussed.