digestive tract & layers overview

What organs make up the digestive tract (alimentary canal or GI tract)?

Oral cavity → Pharynx → Esophagus → Stomach → Small intestine → Large intestine.

What are the accessory organs of the digestive system?

Salivary glands, liver, gallbladder, and pancreas.

What are the four main layers of the GI tract (deep to superficial)?

Mucosa, Submucosa, Muscularis, and Serosa (or Adventitia).

What are the three components of the mucosa layer?

Epithelium, lamina propria, and muscularis mucosae.

What types of epithelium are found in the GI tract mucosa?

Stratified squamous non-keratinized and simple columnar (with or without microvilli and goblet cells).

What cells are found in the GI tract epithelium?

Exocrine cells and enteroendocrine cells.

What is the lamina propria made of and what does it contain?

Areolar connective tissue; contains blood vessels, lymph vessels, and MALT (mucosa-associated lymphatic tissue).

What structures are part of MALT in the lamina propria?

Solitary lymphatic nodules and aggregated lymphatic nodules.

What is the muscularis mucosae and what is its function?

A thin layer of smooth muscle that creates folds in the mucosa to increase surface area.