digestive system Flashcards
What are the 4 stages of digestion?
Ingestion, digestion, absorption, elimination.
What are the organs in the digestive system food goes through?
mouth, esophagus, stomach, small intestine, large intestine, rectum, anus.
What are the accessory organs?
salivary glands, gallbladder, liver, pancreas.
What type of digestion happens in the mouth?
mostly mechanical, but also a little bit of chemical energy.
How is food mechanically digested in the mouth?
It is chewed and moistened with saliva to become a ball called a bolus.
What covers the opening to the trachea so that you don’t breathe your food?
The epiglottis
How is food chemically digested in the mouth?
salivary amylase breaks starches down into disaccharides.
What is peristalsis?
Waves of muscle contractions that move things(food).
What happens in the esophagus?
The bolus moves down the esophagus into the stomach.
What type of digestion happens in the stomach?
Mostly chemical but a little mechanical.
How is food chemically digested in the stomach?
Stomach acid(HCl) activates pepsinogen into pepsin enzyme which breaks down proteins into dipeptides.
How is food mechanically digested in the stomach?
the muscular wall contracts to churn food.
How is the stomach lining protected from HCl?
It secretes a protective mucus that covers the lining.
Where are the sphincters in the stomach?
The cardiac sphincter is at the stomachs entrance and the pyloric sphincter is by the exit of the stomach.
What does the pyloric sphincter do?
It squirts chyme into the duodenum of the small intestine after food has gone through the stomach.
What is acid reflux?
It is commonly known as heartburn and happens when acid from the stomach escapes into the esophagus.
What are gastric ulcers?
Stomach mucus is eroded and the cells lining the stomach are damaged creating an ulcer(sore).
How are gastric ulcers caused?
They can be caused by many different factors including: NSAIDS, Alcohol, gastric hyper-acidity, cigarettes, etc. Also H. Pylori in the pyloric sphincter can cause an ulcer.
What types of digestion occur in the small intestine?
Mostly chemical but a little mechanical.
How does mechanical digestion occur in the small intestine?
Muscles squeeze which breaks up the bits of food.
How does chemical digestion occur in the small intestine?
Bile from the liver breaks up fat(bile is not an enzyme). Juices from the pancreas and intestine break up carbs and proteins.
What enzymes break up carbs in the small intestine?
Pancreatic amylase breaks starches into disaccharides. Disaccharides are broken up into monosaccharides by lactase, sucrase, and others.
What enzymes break up proteins in the small intestine?
Large polypeptides are broken into smaller polypeptides by trypsin and others. Smaller polypeptides are broken into amino acids by peptidases.
How does the small intestine absorb nutrients?
monosaccharides and amino acids are transported from the lumen to the bloodstream to the body cells. Lipid monomers use lymph vessels to get to body cells.
