Digestive System Flashcards
What are catabolic reactions?
reactions that break down molecules
What are anabolic reactions?
reactions that result in net energy storage within cells
As temperature increases, chemical reaction rate ____.
increases
What are endotherms?
animals that produce their own heat as byproducts of metabolic reactions
What are ectotherms?
animals that obtain most of their heat from the environment
While ____ maintain a steady body temperature, ____’ body temperature fluctuates with the environment
endotherms; ectotherms
What is digestion?
the process of breaking down food into smaller molecules that can be absorbed into the body
What are the four stages of digestion?
- ingestion
- digestion
- absorption
- elimination
What is gastrin?
enzyme released by the stomach that stimulates HCl production
What is pepsin?
enzyme that breaks down proteins
What is lipases?
an enzyme that breaks down lipids
What is trypsin?
enzyme that breaks down proteins
What is secretin?
hormone released by duodenum that stimulates pancreas to secrete bicarbonate ions to neutralize stomach acid
What is bile?
fluid produced by the liver and stored in the gallbladder that aids in fat digestion by emulsifying lipids
What is CCK?
hormone released by duodenum that stimulates gallbladder to release bile into duodenum
What happens in the mouth during digestion?
food is ingested and broken down mechanically and chemically by amylase and lipase
What happens in the esophagus during digestion?
food travels from mouth to stomach thru the process of peristalsis
What happens in the stomach during digestion?
- food enters stomach
- gastrin is released
- HCl is produced to increase stomach acidity
- pepsinogen is activated into pepsin
- pepsin breaks down proteins and lipases break down lipids
What happens in the small intestine during digestion?
- duodenum secretes secretin to neutralize small intestine
- chyme from stomach enters the small intestine thru duodenum
- nutrients are absorbed into body
What are chief cells?
cells in the stomach that secrete pepsinogen
What are parietal cells?
cells that release H+ and Cl-
How is pepsin activated in the stomach?
- when food enters the stomach, parietal cells release H+ and Cl, which synthesize into HCl
- chief cells secrete pepsinogen
- high acidity activates pepsinogen → pepsin
- as pepsin levels rise, more pepsinogen is secreted
How do glucose and Na+ enter the intestinal cell from the lumen?
Na+/glucose cotransporters
How does glucose exit the intestinal cell into the extracellular fluid/blood?
glucose transport protein
