Digestive System Overview and Histology

The digestive system is a long, muscular tube that begins at the mouth and ends at the anus. It's responsible for breaking down food into smaller molecules that the body can absorb and use.

The salivary glands produce saliva, which contains enzymes that start the digestion of carbohydrates.

The stomach is a muscular sac that churns food and mixes it with gastric juices, which contain enzymes and acids that break down proteins.

The small intestine is a long, coiled tube where most of the digestion and absorption of nutrients takes place.

The large intestine is a shorter, wider tube where water is absorbed from the remaining food matter and waste is formed.

The mucosa is the innermost layer of the digestive tract wall, containing epithelial cells for protection, secretion, and absorption.

The submucosa is a layer of loose connective tissue beneath the mucosa, containing glands and blood vessels.

The muscularis is a layer of smooth muscle that helps move food through the digestive tract via peristalsis.

The serosa is the outermost layer of the digestive tract wall, protecting and lubricating the organs.

The esophagus is a muscular tube that connects the pharynx to the stomach, allowing food to pass from the mouth to the stomach.

The first part of the small intestine, responsible for receiving chyme from the stomach and mixing it with pancreatic juice and bile.

The middle part of the small intestine where the majority of nutrient absorption occurs.

The last part of the small intestine, responsible for nutrient absorption and absorbing bile salts.

Finger-like projections in the small intestine that increase surface area for nutrient absorption.

The process of moving food through the digestive tract by muscle contractions.

The main digestive enzyme secreted by the pancreas, responsible for breaking down starches into sugars.

The primary hormone secreted by the pancreas that lowers blood glucose levels by stimulating glucose uptake by cells.

The primary hormone secreted by the pancreas that raises blood glucose levels by stimulating glycogen breakdown in the liver.

The largest internal organ, responsible for producing bile and performing many vital metabolic functions.

Star-shaped liver cells that line the sinusoids and perform numerous metabolic functions.

The muscularis layer of the digestive tract has inner circular and outer longitudinal muscle layers responsible for peristalsis.

The mucosa, the innermost layer, has different types of epithelial cells for protection, secretion, and absorption. This is where most of the digestive action happens.

The submucosa layer contains glands and blood vessels. Important for transporting nutrients and creating supportive structures.

The serosa is the outermost layer, protecting and lubricating the digestive organs. It's like the outer lining of the tube.

The stomach churns food and mixes it with gastric juices containing enzymes and acids for protein breakdown.

The small intestine, a long tube, is where most of the digestion and absorption of nutrients happen. This is the primary site of nutrient absorption.

The large intestine, a shorter, wider tube, absorbs water from remaining food and forms waste. This is where waste is formed and compacted.

The pancreas secretes digestive enzymes like amylase and lipase into the small intestine to break down carbohydrates and fats. It also produces insulin and glucagon, hormones that regulate blood sugar.

Blood spaces lined with Kupffer cells (liver macrophages) in the liver, serving as filters for blood.

The pancreas is an organ with both exocrine and endocrine functions. The exocrine part produces digestive enzymes, while the endocrine part secretes hormones like insulin and glucagon.

The liver is responsible for producing bile, an essential substance for lipid digestion.