Gastrointestinal Anatomy: Basic Structure of GI Structure Flashcards
What are the 4 main functions of the GI system?
Motility (transport food and water through the body + waste management)
Absorption (bringing nutrients/water from lumen into the internal environment)
Secretion (synthesisse and reelase enzymes, mucus, and serous fluid into the lumen)
Digestion (break nutrients into smaller pieces)
These are structures that close off ends and separate sections of tube.
Sphincters
What is the type of epithelia found in the mouth/oral cavity and the esophagus? Why?
Stratified squamous epithelium, to protect from abrasion
What is the type of epithelia found in the stomach, small intestine and large intestine? Why?
Simple columnar, because columnar epithelia is much better in secretion and absorption
- has a larger surface area to absorb and secrete material
What is the type of epithelia found in the anus?
Stratified squamous epithelium (to protect from abrasion of the POOP)
Unicellular glands usually contain lots of these cells.
Goblet cells
These cells are columnar, they have apical mucus granules and a basal nucleus
Goblet cells
What are the 2 types of glands?
Simple and compound
What’s the difference between a simple gland and a compound gland?
A simple gland has a single duct (like the stomach and small intestine)
A compound gland has 2 or more ducts (like the salivary glands) - it also has an increased SA to perform more secretions
What are the 4 layers of the gut tube?
Mucosa, submucosa, muscularis (externa/proper), adventitia
This consists of the epithelium, basement membrane and a lamina propria. May contain glands, and has a layer of smooth muscle (muscularis mucosae) that moves mucus and produces tiny localised movements.
Mucosa
This consists of predominantly FCT, glands and blood vessels. It can perform many secretions, of which is regulated by the submucosal nerve plexus.
Submucosa
This layer consists of smooth muscle. It contains the myenteric plexus which is located between layers and regulates motility (transport of food and water and other things in the gut)
Muscularis
What are the 2 layers of the muscularis?
Circular muscle layer (inner) and longitudinal muscle layer (outer)
This is the outermost layer of the gut tube and consists of FCT; this provides support to organ and may also help it to anchor to neighbouring cells.
Adventitia