Digestive System Overview
Chapter Goals
- Name and describe the organs of the digestive system, their locations, and functions.
- Define combining words for organs and related terminology.
- Describe signs, symptoms, and diseases affecting the digestive system.
Main Functions of the Digestive System
- Ingestion: Food taken into the mouth.
- Digestion: Breakdown of food both mechanically (by teeth) and chemically (by stomach and small intestine).
- Enzymes aid in breaking down complex nutrients:
- Proteins → Amino acids
- Sugars → Glucose
- Fats → Fatty acids/triglycerides
- Absorption: Nutrients absorbed in the small intestine, entering the bloodstream.
- Elimination: Removal of solid waste not absorbed into the bloodstream.
- Large intestine concentrates waste and passes it out through the anus.
Anatomy of the Digestive System
- Oral Cavity: Cheeks, lips, hard & soft palate, rugae, uvula, tongue, tonsils, gums, teeth, pharynx.
- Teeth Structure: Crown, root, enamel, dentin, pulp, gingiva, cementum, root canal.
- Process of Swallowing (Deglutition):
- Involves the oral cavity, pharynx, esophagus, epiglottis, and trachea.
Stomach and Intestines
- Stomach: Lower esophageal sphincter, fundus, curvatures, rugae, body, antrum, pylorus.
- Esophagus: Muscular tube moving the bolus to the stomach.
- Small Intestine: Duodenum, jejunum, ileum.
- Large Intestine: Cecum, colon segments, rectum, anus.
Accessory Organs and Their Roles
- Liver: Produces bile, regulates glucose, manufactures blood proteins, detoxifies.
- Gallbladder: Stores bile.
- Pancreas: Produces enzymes (amylase, lipase, protease) and insulin.
Vocabulary and Key Concepts
- Enzymes: Catalysts in digestion (e.g., amylase, lipase, protease).
- Bile: Produced by the liver, stored in the gallbladder, aids in fat digestion.
- Peristalsis: Rhythmic contractions moving food through the digestive tract.
- Absorption: Movement of nutrients into the bloodstream.
- Villi: Small projections in the small intestine aiding nutrient absorption.
Common Conditions and Terms
- Jaundice: Caused by high levels of bilirubin.
- Hyperbilirubinemia: Excess bilirubin in the blood.
- Insulin: Hormone reducing blood sugar by promoting uptake into cells.
Key Questions and Terminology
- What are the parts of the oral cavity?
- What is mastication and deglutition?
- How does the liver maintain blood glucose levels?
- What is the role of bile and how is it produced?
- What processes are affected if enzymes are absent or dysfunctional?
This introductory guide to the digestive system provides a comprehensive overview of its structure and function, and sets the stage for learning medical terminology associated with it.