Digestive System Flashcards
What is the role of the digestive system?
It is specialized to breakdown food both physically and chemically and then absorb the nutrients into the bloodstream.
What are the four components(steps) of digestion?
1) Ingest
2) Digestion
3) Absorption
4) Egestion
What is ingestion?
Ingestion is the taking in of nutrients
What happens during digestion?
The breaking down of organic molecules into smaller complexes
What is absorbtion?
The transport of digested nutrients to the tissues of the body
What is egestion?
The removal of materials from the food that the body cannot digest
Where does digestion begin?
The mouth
What type of digestion begins in the mouth? Physical or chemical?
Physical
How is physical breakdown started in the mouth?
Food is chewed by the teeth.
Why is it important for food to be chewed?
To make it easier for chemicals to work on it.
What does the tongue do in the digestive system?
Rolls food into a ball-like mass called a bolus. The tongue then pushes it to the back of the mouth for swallowing.
How does chemical digestion happen in the mouth?
An enzyme called salivary amylase produced by the salivary glands break down starch in the mouth into disaccharides.
What is the pharynx?
Connects the esophagus to the trachea.
What is the epiglottis?
a cartilage flap that closes over the trachea when food is being swallowed.
What is the esophagus made up of?
Smooth muscle and cartilaginous rings.
What is secreted in the esophagus?
mucus
What does the esophagus do?
Moves bolus to the stomach through peristalsis.
What is peristalsis?
wavelike contractions of muscle to push food through
How many layers does the stomach have?
4
What do the 3 outer layers of the stomach do?
Mix food with gastric secretions to create chyme.
What the ridges on the innermost layer of the stomach called?
Rugae
What is in gastric juice?
water, mucus, salt, HCl and enzymes
What is the pyloric sphincter?
A valve at the lower end of the stomach that controls the passing of food into the small intestine.
Where does protein digestion start?
The stomach
What lines the stomach?
secretory cells
What are secretory cells?
cells that secrete things
Where does most of food absorption happen?
The small intestine
What 3 things are absorbed in the stomach?
Water, certain vitamins, alcohol
What does the esophagel sphincter do?
Controls the entry of food into the stomach.
What physical breakdown happens in the stomach?
Peristalsis pushes food around in the stomach breaking it down to form chyme.
What is chyme?
A thick mixture of food and gastric juices.
What is responsible for chemical breakdown in the stomach?
Gastric juice
What does HCl in the stomach do to protiens?
Begins to soften and break them down
What happens to amylase in the stomach?
It denatures as the HCl in the stomach is to acidic
What stimulated the production of Gastrin?
The anticipation of eating
What is gastrin?
A hormone found in the stomach.