Ch. 23 Review Flashcards
List the 6 major activities involved in the processing of food
- Ingestion
- Mechanical Breakdown
- Propulsion
- Digestion
- Absorption
- Defecation
These activities are the functions of the digestive system.
What are the layers of the alimentary canal?
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
The mucosa layer includes epithelium, lamina propria, and muscularis mucosae.
Describe the mucosa layer of the alimentary canal.
The mucosa consists of:
* Epithelial lining (simple columnar)
* Lamina propria (loose areolar CT)
* Muscularis mucosae (smooth muscle)
Functions include secretion, absorption, and protection.
What is the tissue type of the submucosa?
Areolar connective tissue
The submucosa is highly vascular and contains blood and lymph vessels.
What are the two major layers of the muscularis external?
- Inner Circular layer
- Outer Longitudinal layer
The inner circular layer can thicken to form sphincters.
What is the tissue type of the serosa?
Areolar connective tissue covered with mesothelium
The serosa is also known as the visceral peritoneum.
What epithelial tissue type is found in the mouth?
Stratified squamous epithelium
It is keratinized in some areas.
What type of epithelium is found in the stomach?
Simple columnar epithelium
All cells in the stomach are secretory.
What are the names of the sphincters in the digestive system?
- Lower esophageal sphincter (cardiac sphincter)
- Pyloric sphincter
- Ileocecal sphincter
- Hepatopancreatic sphincter
These sphincters control food passage and secretion.
What adaptations does the stomach have to its muscularis externa?
It has an additional oblique muscle layer
This aids in breaking down food and moving it to the small intestine.
What is the primary function of gastric mucous neck cells?
To produce thin mucus that protects the stomach lining
This mucus protects against gastric acid.
What hormone controls the secretion of gastric juices?
Gastrin
It regulates HCl secretion and digestive enzymes.
What are the phases of gastric secretion regulation?
- Cephalic phase
- Gastric phase
- Intestinal phase
Each phase has distinct triggers and effects on gastric secretion.
What is the major type of motility in the stomach?
Peristalsis
It aids in mechanical breakdown and propulsion of chyme.
What are the three major modifications of the small intestine wall?
- Circular folds
- Villi
- Microvilli (brush border)
These structures increase surface area for absorption.
What is the role of the simple columnar absorptive cells in the small intestine?
To absorb nutrients and electrolytes from digested food
These cells are primarily found in the epithelial villus mucosa.
What do intestinal crypts secrete?
Intestinal juice (water with mucus)
They help absorb nutrients and contain various cell types.
What are the two types of motility found in the small intestine?
- Segmentation
- Peristalsis
Segmentation mixes chyme, while peristalsis moves food residue towards the large intestine.
What is the main digestive role of the liver?
To produce bile
Bile helps emulsify fats.
What are the three functions of hepatocytes?
- Glycogen storage
- Protein production
- Detoxification
They metabolize and inactivate various compounds.
What is the function of the gall bladder?
To store excess bile
It releases bile into the small intestine when needed.
What are the major functions of pancreatic juice?
Contains enzymes that breakdown all categories of food
Produced by acinar cells.
Describe the unique structural features of the large intestine.
- Teniae coli
- Haustra
- Epiploic appendages
These structures contribute to the function and appearance of the large intestine.
What is the gastroileum reflex?
Caused by stomach activity and gastrin release leading to increased ileum segmentation
It helps push food residues into the large intestine.