Unit 5: Digestive System Flashcards
What organs are a part of the digestive tract?
Mouth, pharynx, esophagus, stomach, small intestine, large intestine
accessory organs: liver, pancreas, gall bladder
What does the mouth do?
Food is masticated and shaped into a bolus to be swallowed
The tongue tastes the food using chemoreceptors and teeth break down the food. The palate separates the nasal cavity from the mouth cavity and the salivary glands produce saliva to assist digestion
What does the pharynx do?
Region between the mouth and esophagus. The epiglottis blocks the glottis of the trachea so food does not enter the respiratory system
What does the esophagus do?
It is a muscular tube that acts as the pathway for food to travel from the pharynx to the stomach. Food moves through peristalsis.
There is a lower esophageal sphincter, which prevents backflow of acidic stomach components.
What does the stomach do?
Responsible for some of the digestion of the food. It has rugae, thick folds that allows for expansion.
Digestion begins from the molecule gastrin, a hormone that is secreted when the stomach begins stretching. It signals for the release of gastric juice.
What is the role of the small intestine?
Most chemical digestion occurs here!!
Responsible for the absorption of nutrients. It is longer than the large intestine but smaller in diameter. It contains villi to increase the surface area
Composition:
Duodenum: first section, site of the common bile duct. Secretes bile and pancreatic juice (basic) to counteract the acidity of the chyme
Jejunum: middle portion
Ileum: includes peyer’s patches which regulates presence of pathogenic bacteria
What are digestive secretions controlled by?
Hormones secretin and CCK (Cholecystokinin)
secretin is regulatory and is released when there is low pH in the duodenum
cck helps digest protein and fat in duodenum and is released when there are partially digested proteins and fats
What makes up the large intestine?
Cecum, colon, rectum, anal canal
Main role of large intestine?
Absorb water, salts, nutrients and store undigested material until it can be released
What does the colon do?
Removes water from digested material
What does the pancreas do?
Exocrine (secrete to ductal) and endocrine (secrete to bloodstream)
exocrine: produces pancreatic juice to neutralize stomach acid and produces digestive enzymes
endocrine: produces insulin, glucagon, somatostatin
What does the liver do?
Detoxifies and synthesizes proteins
Produces bile
What does the gallbladder do?
Holds excess bile from the liver and sends to duodenum when needed
