Chapter 8- Digestive System Flashcards
What is the definition of digestion?
Both physical and chemical processes that reduce food to small soluble molecules that can be absorbed
What are the substances that can be absorbed? (4)
- amino acids
- sugars of carbohydrates
- glycerol and fatty acids of fats
- some minerals and water
What are used in chemical digestion?
Enzymes
Function of the mouth
Stores food while being chewed, place where saliva is mixed with food
Function of lips
Hold food in oral cavity, help direct food onto teeth
Function of teeth
Breaks food into smaller pieces to create a higher surface area for enzymes to work on
Function of salivary glands
Produce saliva for moistening and chemically digesting food
Function of the tongue
Directs food onto teeth, pushes food towards pharynx
Function and location of the pharynx
Where swallowing occurs, back of throat
Function of the epiglottis
Closes off trachea, prevents food from entering air passage
Function of the esophagus
Food is transported from the mouth to the stomach by peristalsis
What occurs when food is being swallowed and breathing occurs at the same time?
Choking
What is peristalsis
The rhythmical contraction of the esophageal wall/ intestinal tract
Function of the cardiac sphincter
Closes off the top part of the stomach to prevent food from being regurgitated into the esophagus
Function of stomach
Stores and churns food; helps with physical digestion
Where does the digestion of protein occur?
The stomach
What is made out of the food in the stomach?
Acid chyme
Where and why is gastrin produced?
Lower stomach, stimulates gastric glands to produce pepsinogen and HCl
What do pepsinogen and HCl react to produce?
Pepsin
What is the function of pepsin?
Chemically digests proteins to peptides
Function of the pyloric sphincter
Closes off the lower part of the stomach so that only a small amount of chyme enters the small intestine
What occurs in the duodenum?
Enzymes from the pancreas and the small intestine digest all 3 food groups here
Function and location of bile
Made in liver, stored in gall bladder, secreted into the small intestine, emulsifies fat
Function of the pancreas
Produces enzymes and sodium bicarbonate (neutralizes the acidic chyme)
Function of the gall bladder
Stores bile
Function of the liver
Produces bile
Function of the small intestine
Final digestion and absorption of nutrients
What are the two most important hormones secreted by the duodenal wall, and their functions
- Secretin: stimulates the release of pancreatic juices
* Cholocytokinin: stimulates the release of bile from the gall bladder
