Digestive System Overview

Digestive System Overview

• The digestive system is an organ system responsible for taking in food, digesting it, absorbing nutrients, and excreting waste
• It comprises the digestive tract and accessory organs
• The digestive tract includes the mouth, esophagus, stomach, small intestine, and large intestine

Digestive Tract

• The digestive tract forms a continuous pathway
• Food moves through the tract in a unidirectional manner
• Digestion is achieved through mechanical and chemical processes

Mechanical Digestion

• Mechanical digestion involves physically breaking down food into smaller pieces
• Includes actions like chewing (in the mouth) and churning (in the stomach)

Chemical Digestion

• Chemical digestion involves breaking down food into simpler molecules using enzymes and chemicals
• Happens in the mouth (saliva) and stomach (acids and enzymes) to the small intestine

Oral Cavity (Mouth)

• Teeth (incisors, canines, premolars, molars): used for tearing, grinding, and crushing food
• Tongue: manipulates food during chewing, pushing food back to the molars
• Salivary glands: produce amylase, an enzyme which breaks down starch and moistens food
• Resulting food mass is called a bolus

Esophagus

• A muscular tube connecting the mouth to the stomach
• 2 cm in diameter
• The cardiac sphincter is the connection point between the esophagus and the stomach
• Peristalsis, muscle contractions, moves the bolus through the esophagus and into the stomach

Stomach

• J-shaped organ used to store and digest food
• Mechanical digestion: smooth muscles churn bolus into chyme
• Chemical digestion: digestive juices (enzymes and acids) break down food molecules
• Chyme is released into the small intestine through the pyloric sphincter

Small Intestine

• Major site for digestion and absorption of nutrients into the bloodstream
• Three parts: duodenum, jejunum, ileum
• Approximately 6 meters long

Accessory Organs

• Organs that play a supporting or supplementary role in the digestive process
• Includes the liver, gallbladder, and pancreas

Liver

• Organ that produces bile
• Bile helps break down fats into smaller molecules
• Bile is released into the duodenum

Gallbladder

• Stores bile produced by the liver
• Releases bile into the small intestine to aid digestion

Pancreas

• Secretes pancreatic juice containing digestive enzymes
• Breaks down carbohydrates, proteins, and fats
• Also produces insulin, which regulates blood glucose levels

Large Intestine

• Absorbs water and vitamins from undigested matter
• About 1.5 meters long but wider than the small intestine
• Stores undigested matter and toxins in the rectum
• Excretes waste in the form of feces through the anus.

This quiz covers the key aspects of the digestive system, including the structure and function of the digestive tract and the processes involved in mechanical and chemical digestion. You'll explore how food is processed from ingestion to waste excretion. Test your knowledge on the organs involved and their roles in digestion.