Digestive System Overview Quiz

Overview

• The digestive system is a complex network of organs working together to break down food into absorbable nutrients, providing the body with energy and building blocks for cells.
• It involves both mechanical and chemical processes.
• Key players include the mouth, esophagus, stomach, small intestine, large intestine, and accessory organs like the liver, pancreas, and gallbladder.

Mouth

• Mechanical digestion begins in the mouth with chewing (mastication).
• Saliva, containing enzymes like amylase, initiates chemical digestion, breaking down carbohydrates.
• Tongue shapes food into a bolus for swallowing.

Esophagus

• Muscular tube connecting the mouth to the stomach.
• Peristalsis, wave-like muscle contractions, moves food through the esophagus.
• Epiglottis prevents food from entering the trachea (windpipe).

Stomach

• J-shaped organ that stores and partially digests food.
• Muscular contractions churn the food (mechanical digestion).
• Gastric glands secrete gastric juice, containing hydrochloric acid (HCl) and enzymes like pepsin, initiating protein digestion.
• Mucus protects the stomach lining from acid.

Small Intestine

• Long, coiled tube where most nutrient absorption occurs.
• Divided into three sections: duodenum, jejunum, and ileum.
• Duodenum receives secretions from the pancreas and liver, which further digest proteins, carbohydrates, and fats.
• Enzymes like maltase, sucrase, and lactase break down further carbohydrates.
• Villi and microvilli increase the surface area for absorption.
• Nutrients are absorbed into the bloodstream.

Large Intestine

• Wider and shorter than the small intestine.
• Absorbs water and electrolytes from undigested food.
• Houses beneficial bacteria that aid in further digestion and vitamin production.
• Forms and stores feces.
• Processes undigested material into feces.

Accessory Organs

• Liver: produces bile, crucial for fat digestion and absorption.
• Gallbladder: stores and concentrates bile.
• Pancreas: produces numerous digestive enzymes and bicarbonate to neutralize stomach acid.
• Pancreatic enzymes break down carbohydrates, proteins, and fats.
• Bicarbonate neutralizes the acidic chyme (partially digested food from stomach) entering the small intestine.

Disorders and Problems

• Heartburn: burning sensation in the esophagus due to acid reflux.
• Peptic ulcers: sores in the lining of the stomach or duodenum caused by bacteria (H. pylori) or excessive acid production.
• Irritable bowel syndrome (IBS): chronic disorder causing abdominal pain, bloating, and changes in bowel habits.
• Inflammatory bowel disease (IBD): includes Crohn's disease and ulcerative colitis, causing inflammation in the digestive tract.
• Diverticulitis: inflammation of small pouches in the digestive tract.
• Celiac disease: an autoimmune disorder triggered by gluten consumption, leading to damage in the small intestine.
• Gallstones: solid crystalline masses formed in the gallbladder.

Digestive Processes

• Mechanical digestion involves physical breakdown of food.
• Chemical digestion uses enzymes to break down food into simpler molecules.
• Absorption is the process of moving nutrients from the digestive tract into the bloodstream.
• Elimination is the removal of undigested material from the body.