Overview of the Digestive System

Mouth
- Mechanical digestion through chewing.
- Saliva contains enzymes (amylase) for chemical digestion of carbohydrates.
Esophagus
- Transports food from the mouth to the stomach via peristalsis (muscle contractions).
Stomach
- Temporarily stores food, mixes it with gastric juices (acid and enzymes).
- Begins protein digestion (pepsin) and converts food into chyme.
Small Intestine
- Consists of three sections: duodenum, jejunum, ileum.
- Primary site for nutrient absorption.
- Pancreatic enzymes and bile aid in fat digestion.
Large Intestine (Colon)
- Absorbs water and electrolytes.
- Forms waste (feces) for elimination.
- Houses beneficial bacteria (gut microbiota) that aid digestion.
Rectum and Anus
- Rectum stores feces until elimination.
- Anus controls fecal excretion through sphincters.

Salivary Glands: Produce saliva that contains enzymes for carbohydrate digestion.
Liver: Produces bile, which emulsifies fats.
Gallbladder: Stores bile until needed for digestion.
Pancreas: Produces digestive enzymes (lipase, amylase, proteases) and bicarbonate to neutralize stomach acid.

Ingestion: Intake of food through the mouth.
Mechanical Digestion: Physical breakdown of food (chewing, churning in the stomach).
Chemical Digestion: Enzymatic breakdown of complex molecules into simpler forms.
Absorption: Nutrients absorbed through the intestinal walls into the bloodstream.
Elimination: Disposal of indigestible substances as feces.

Hormones (e.g., gastrin, secretin, cholecystokinin) regulate digestive processes and enzyme secretion.
Nervous system influences digestive activity through the enteric nervous system.

Gastroesophageal Reflux Disease (GERD): Acid reflux causing heartburn.
Irritable Bowel Syndrome (IBS): Affects the large intestine, causing cramping, diarrhea, and constipation.
Celiac Disease: Immune response to gluten leads to intestinal damage.
Peptic Ulcers: Sores in the stomach lining due to excess acid or H. pylori infection.

Provides essential nutrients required for the functioning of the digestive system.
Supports overall health and prevents digestive disorders.

The digestive system is responsible for breaking down food into nutrients that the body can absorb and use.
It involves four major processes: ingestion, digestion, absorption, and elimination.

Mouth: Chewing begins mechanical digestion. Saliva contains amylase for the chemical digestion of carbohydrates.
Esophagus: Uses peristalsis (muscle contractions) to move food from the mouth to the stomach.
Stomach: Temporarily stores food, mixes it with gastric juices (acid and enzymes), and begins protein digestion with pepsin. Converts food into chyme.
Small Intestine: Divided into three sections: duodenum, jejunum, and ileum. The primary site for nutrient absorption, where pancreatic enzymes and bile aid in fat digestion.
Large Intestine (Colon): Absorbs water and electrolytes. Forms waste (feces) for elimination. Houses beneficial bacteria (gut microbiota) that aid digestion.
Rectum and Anus: Rectum stores feces until elimination. The anus controls fecal excretion through sphincters.

Salivary Glands: Produce saliva containing enzymes for carbohydrate digestion.
Liver: Manufactures bile, which emulsifies fats.
Gallbladder: Stores bile until needed for digestion.
Pancreas: Produces digestive enzymes (lipase, amylase, proteases) and bicarbonate to neutralize stomach acid.

Ingestion: Taking in food through the mouth.
Mechanical Digestion: The physical breakdown of food, including chewing and churning in the stomach.
Chemical Digestion: Enzymatic breakdown of complex molecules into simpler forms.
Absorption: Nutrients are absorbed through the intestinal walls into the bloodstream.
Elimination: Disposal of indigestible substances as feces.

Hormones: Regulate digestive processes and enzyme secretion. Examples include gastrin, secretin, and cholecystokinin.
Nervous System: Influences digestive activity through the enteric nervous system.

Gastroesophageal Reflux Disease (GERD): Acid reflux causing heartburn.
Irritable Bowel Syndrome (IBS): Affects the large intestine, causing cramping, diarrhea, and constipation.
Celiac Disease: Immune response to gluten leads to intestinal damage.
Peptic Ulcers: Sores in the stomach lining due to excess acid or H.pylori infection.