Gastrointestinal System
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What is the purpose of the gastrointestinal system?
Converts food into nutrients the body can use
What processes convert food into nutrients?
Digestion and absorption
Explain the process of digestion
Is the chemical and mechanical breakdown of foods into smaller compounds that can be utilized by the body
Explain the how food is generally absorbed after digestion
The nutrients are moved from the intestines (where absorption occurs) into the bloodstream
What is the alimentary canal?
The pathway in the body though which food travels while being digested and absorbed -as well as the accessory organs that release secretions necessary for digestion to occur
Pathway of food from mouth to being expelled
Mouth > pharynx > esophagus > esophageal sphincter > stomach > pyloric sphincter > small intestine (duodenum, jejenum, ileum) > cecum > large intestine (ascending, transverse, depending) > rectum > anus
Is food mechanically or chemically digested in the mouth?
Both! Mechanical=chewing Chemical: salivary glands releasing digestive enzymes
What is a bolus?
The chewed up food within the mouth
Explain peristalsis
A wavelike contraction of smooth muscle that moves digested material along the digestive tract
What occurs in the stomach?
The hollow organ below the esophagus where mechanical and chemical digestion occur
What structure separates the esophagus and the stomach?
Esophageal sphincter
What structure separates the stomach and the small intestine?
Pyloric sphincter
What is the typical pH of the stomach?
1-2
What causes the environment of the stomach to be so acidic?
The acidity is maintained by the gastric juices (HCl, enzymes that begin the chemical digestion of protein)
Once the bolus has been mechanically and chemically digested in the stomach, what does it become?
Chyme
Where does absorption start?
Small intestine
What are the 3 parts of the small intestine?
duodenum, jejenum, ileum
Which structures aid in absorption by releasing digestive secretions in the duodenum?
Liver and gallbladder
What does the liver and gallbladder release in the duodenum?
Bile
Where is Bile created and stored?
Created in the liver Stored in the gallbladder
How does bile get secreted into the duodenum?
Though the common bile duct
What macromolecules are digested in the duodenum?
Carbohydrates, protein, fats
The small intestine is lined with what structure to aid in absorption?
Villi/microvilli
What are functions of villi/microvilli?
Finger like folds in the lining of the intestine that increase surface area to aid absorption