GI Tract Flashcards
What is digestion?
The process of transforming the foods we eat into units for absorption.
Define absorption.
The movement of substances into or across tissues; particularly, the passage of nutrients into the gastrointestinal tract and then into the bloodstream.
What are cephalic phase responses?
The responses of the parasympathetic nervous system to the sight, smell, thought, and sound of food.
List the components of the gastrointestinal (GI) tract.
- Mouth
- Esophagus
- Stomach
- Small intestine
- Large intestine (colon)
- Rectum
- Anus
What is the mucosa?
The innermost layer of the gastrointestinal tract, composed of epithelial cells and glands.
What is the function of sphincters in the GI tract?
To control the flow of material between different parts of the GI tract.
What is chyme?
A mass of partially digested food and digestive juices moving from the stomach into the duodenum.
Define peristalsis.
The wavelike, rhythmic muscular contractions of the GI tract that propel its contents down the tract.
What is the role of enzymes in digestion?
Large proteins that accelerate the rate of chemical reactions without being altered in the process.
What is hydrolysis?
A reaction that breaks apart a compound through the addition of water.
Define passive diffusion.
The movement of substances into or out of cells without energy expenditure or transport proteins.
What is active transport?
The movement of substances into or out of cells against a concentration gradient, requiring energy (ATP).
What is endocytosis?
The uptake of material by a cell through membrane indentation and pinching off to form a vesicle.
What are emulsifiers?
Agents that blend fatty and watery liquids by promoting the breakdown of fat into small particles.
What is the function of the liver in digestion?
Produces and secretes bile, detoxifies harmful substances, and helps metabolise carbohydrates, lipids, proteins, and micronutrients.
What is bile?
An alkaline, yellow-green fluid produced in the liver that emulsifies dietary fats.
What is the role of cholecystokinin (CCK)?
A hormone that stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder.
What is amylase?
A salivary enzyme that catalyses the hydrolysis of amylose, a starch.
What is the function of the pyloric sphincter?
Regulates the passage of food from the stomach into the duodenum.
What is the primary function of the small intestine?
Completion of digestion and absorption of nutrients.
What are villi?
Small, finger-like projections that blanket the folds in the lining of the small intestine.
Define the term ‘lymph’.
Fluid that travels through the lymphatic system, made up of fluid drained from between cells and large fat particles.
What is constipation?
Infrequent and difficult bowel movements, followed by a sensation of incomplete evacuation.
Describe diarrhea.
Loose, watery stools that occur more than three times in one day due to rapid movement through the large intestine.
