GI System Flashcards
What does the epiglottis do?
During the swallowing process it covers the trachea, this preventing food from going down the respiratory tract
How does the mouth digest food?
Chewing mechanically breaks down the food whilst taste buds stimulate the production of saliva that contains the enzyme amylase which breaks down carbohydrates into glucose.
Define peristalsis
The involuntary constriction and relaxation of the muscles of the intestine. This creates wave like motion which push the contents along the canal.
How does the stomach digest food?
The stomach digests food by continuing peristalsis to mechanically break down the food as well as producing acidic gastric juices which chemically digests the contents. This forms chyme. The stomach also produces pepsin.
What does pepsin do?
Pepsin is an enzyme found in the stomach which breaks down proteins into smaller chain amino acids
Name the sphincter a if the GI tract.
Upper oesophageal sphincter Lower oesophageal sphincter Pyloric sphincter Ileocecal sphincter Involuntary and voluntary anal sphincters
How is bile created?
The liver secretes diluted bile into the gallbladder which stores and concentrates it before being released into the small intestine
How does bile work?
Bile emulsifies fats so they can be digested more easily
What are the components of pancreatic juice?
There are two main components. Firstly an alkaline solution consisting if bicarbonate and water whose purpose is to neutralise the acidic stomach contents. It comes from the epithelial cells of the pancreatic ducts.
Secondly it contains digestive enzymes including lipase for fat molecules, pancreatic amylase for carbs and trypsin and chymotrypsin to break up peptide fragments.
What is the purpose of the small intestine?
Primary function is to digest and absorb through the epithelial cells of the villi. The majority is absorbed in the jejunum with exceptions for iron in duodenum, vit B12 and bike salts in terminal ileum
Name the three structural parts to the small intestine.
Duodenum
Jejunum
Ileum
What is the purpose of the large intestine?
The main function is to absorb water back into the system, therefore concentrating the bodies waste material into feces
What nutrients are required by cells?
Source of energy -brain relies only on glucose 20 amino acids (8 essential) Vitamins Minerals/trace elements Essential fatty acids Water
Name some examples of water soluble nutrients.
Glucose
Amino acid
Vitamin B & C
Name some fat soluble nutrients.
Essential fatty acids
Chylomicra (lipid particles emulsified by bile)
Vitamins A, D, E, K
