digestive system Flashcards
What are the main components of the digestive system?
Gastrointestinal tract and accessory digestive organs
Accessory digestive organs include salivary glands, pancreas, liver, and gall bladder.
What is the alimentary canal?
A continuous tube from mouth to anus
It includes the mouth, pharynx, oesophagus, stomach, small and large intestines, rectum, and anus.
What are the four main layers of the digestive tract?
Mucosa, submucosa, muscularis, serosa
Each layer has specific functions related to digestion and absorption.
What is the function of the mucosa layer?
Forms the surface of the lumen and acts as a protective surface
It is made of a mucus membrane (epithelial layer).
What role does the submucosa play in the digestive tract?
Provides elasticity and distensibility, contains blood supply, glands, and nerves.
What is the muscularis layer composed of?
Smooth muscle coat with inner circular and outer longitudinal muscle layers.
What is the function of peristalsis?
Produces contractions to push food along the digestive tract.
What initiates digestion in the mouth?
Mechanical breakdown by teeth and tongue, and secretion of salivary amylase.
What is chyme?
The semi-liquid mass of partially digested food that leaves the stomach.
What are the types of cells found in gastric glands?
Zymogenic, parietal, mucous, enteroendocrine.
What is the primary function of the small intestine?
Majority of chemical digestion and absorption of nutrients.
What are the three regions of the small intestine?
Duodenum, jejunum, ileum.
What increases the surface area for absorption in the small intestine?
Villi and microvilli.
What is the main function of the large intestine?
Water reabsorption and storage of faecal material.
What are the three main ways matter is moved through the large intestine?
Haustral churning, peristalsis, mass peristalsis.
What does gastrin stimulate?
Production of HCl in the stomach.
What is the role of secretin?
Stimulates the pancreas to produce bicarbonate.
What does cholecystokinin (CCK) stimulate?
Production of pancreatic juice and contraction of the gall bladder.
What is the role of the pancreas in digestion?
Secretes digestive enzymes and bicarbonate to neutralize stomach acid.
What is the function of bile?
Emulsifies fats and neutralizes acidic chyme.
What happens during the cephalic phase of digestion?
Initiated by sight, smell, or thought of food, leading to increased gastric secretions.
What triggers the intestinal phase of digestion?
Presence of fatty acids and glucose in the duodenum.
What is the function of the gall bladder?
Stores bile produced by the liver.
What are the enzymes involved in protein digestion?
Peptidases/proteases.
Fill in the blank: The liver metabolizes the products of digestion which enter via the _______.
Hepatic portal vein.
True or False: Digestion occurs in the oesophagus.
False.
What is the role of goblet cells in the large intestine?
Secrete mucus.
What is the function of the vagus nerve in digestion?
Stimulates digestion by increasing gut motility and promoting enzyme secretion.
