Unit 4: Digestion Flashcards
What does the mouth do?
It eats and swallows food by chewing and mixing it with saliva. Saliva contains lubricants and enzymes that start starch digestion.
What does the esophagus do?
It moves food from the mouth to the stomch by peristalsis.
What does the stomach do?
It churns the food in secreted water and acid to kill of foreign bacteria. It is also involved in the inital stages of protein digestion.
What does the small intestine do?
It carries out the final stages of digestion of lipids, carbs, proteins, and nucleic acids. It also neturalizes stomach acid and absorbs nutrients. Plus, it breaks disacchirides into monosacchirides.
What does the pancreas do?
It secrets lipase, amylase, and protease (the enzymes).
What does the liver and gall bladder do?
The liver breaks up lipid droplets by secreting surfactants in the bile and the gall bladder regulates the release of the bile and stores it.
What does the large intestine do?
It reabsorbs water and does further digestion (especially of carbs). It also forms and stores feces/stool.
What does the rectum and anus do?
They temporarily store the feces and control defecation.
What is the enzyme, exocrine glands, and what do they do?
They include the salivary glands, pancreas, stomach, and small intestine glands. They secrete specific components through ducts (channels). Enzymes are very important to the digestive system.
How are most enzymes made?
By the cells that line the small intestine.
Amylase–
is secreted from the MOUTH and PANCREAS. Its substrate/macromolecule is STARCH and the product/monomer is MALTOSE.
Pepsin (protease)–
is secreted from the STOMACH. Its substrate is PROTEIN (POLYPEPTIDE) and the product is DIPEPTIDES.
Trypsin (protease)–
is secreted from the PANCREAS. Its substrate is PROTEIN (POLYPEPTIDE) and the product is DIPEPTIDES.
Lipase–
is secreted from the PANCREAS. Its substrate is LIPIDS and the product is GLYCEROL & FATTY ACIDS.
Amylase (enzyme) can fit and break 1,4 bonds in amylose and amylopectin forming maltose. What does amylase make when it can’t attach and break the 1,6 bonds?
It makes a third sugar called dextrin (small polysaccharide).
How does folded stomach lining affect the stomach?
It creates gastric pits which contains the neccesary cells to secrete components of the digestive juices.
How are gastric pits created and what do they contain?
They are created due to the high folding in the stomach lining and they are full of cells that secrete various components of the digestive juices.
What are mucus cells?
They give a protective mucus layer that protects the lining from the enzymes and acidic (low) pH. It can be damaged by H. pylori bacteria which leads to open sores or ulcers (acids and enzymes eat away at the epithelial layer).
What are pariental cells?
These secrete an acid that kills ingested bacteria and they use acidic pH to convert pepsinogen into active pepsin.
What are chief cells?
They secrete inactive pepsinogen and stay inactive so thst the chief cells don’t become digested.
What are G (gastrin) cells?
This secretes the hormone gastrin which stimulates parietal and chief cells to secrete enzymes and acid.
What is peristalisis?
It is when the stomach walls contract and mechanically digest food.
What activates protein digestion?
The HCI that is contained in the gastric juice activates pepsinogen converting it to pepsin that digests protein.
