Digestive System Flashcards
Role of carbohydrates in the body
main source of energy
Role of proteins in the body
provide raw materials for growth and repair of structures
Role of lipids in the body
make up the cell membrane and help the body absorb fat-soluble vitamins
Role of vitamins in the body
helps body preform chemical reactions
Role of minerals in the body
participates in a variety of things (calcium for bones, iron for hemoglobin)
needed to replace minerals lost in sweat, urine, and digestive wastes
Role of water in the body
help in bodily processes where many chemical reactions happen in water, makes up the bulk of blood and other bodily fluids, prevents overheating
Functions of the Digestive System
to convert food into small molecules that the cells of the body can use (and get rid of the unnecessary parts of food)
What are the four stages of digestion?
ingestion, digestion, absorption, and elimination
What happens during ingestion?
food goes into the mouth
What happens during digestion?
food is broken down into smaller molecules (mouth, stomach, small intestine)
What happens during absorption?
small molecules are absorbed into the small intestine and enter the circulatory system (through blood vessels)
nutrients leave the alimentary canal and enter the circulatory system to be delivered to cells
What happens during elimination?
substances that cannot be digested or absorbed go through the large intestine and leave the body as feces out the anus
What enzyme breaks down proteins in the stomach?
pepsin
What enzyme breaks down proteins in the small intestine?
trypsin
Alimentary Canal
the organs that food passes through whilst being digested; the pathway of food
Accessory Organs
organs that aid the digestive process but food does not pass through it
What organs make up the alimentary canal?
mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus
What organs are accessory organs?
salivary glands, liver, gallbladder, pancreas, bile duct
Why are organs of the alimentary canal and accessory organs separated into two categories?
alimentary canal has food passing through and is directly involved
accessory organs do not have food passing through and only provides support
their roles and functions in the digestive system are different
Mechanical Digestion
physical breakdown of food into smaller pieces to increase surface area
Chemical Digestion
chemical breakdown of large molecules into molecules small enough to enter cells (enzymes)
Where does digestion happen?
mouth, stomach, small intestine
How is food mechanically digested in the mouth?
chewing by teeth grinds and cuts food
also tongue by moving food around
How is food mechanically digested in the stomach?
3 layers of smooth muscle in the stomach churn the bolus
How is food mechanically digested in the small intestine?
bile produced by liver and released by gallbladder into the bile duct breaks large globs of fats into smaller droplets
How is food chemically digested in the mouth?
salivary amylase breaks down carbs into monosaccharides
How is food chemically digested in the stomach?
pepsin breaks down proteins into peptides and amino acids
How is food chemically digested in the small intestine?
lipase - lipids into glycerol and fatty acids
sucrase, maltase, lactase, amylase - carbs into monosaccharides
trypsin - proteins into amino acids
Bile
a fluid loaded with lipids and salts
What produces bile?
the liver
Where is bile stored?
in the gallbladder
Where is bile released?
into the small intestine using the bile duct
What is bile used for?
to emulsify fats (to break down large fats into smaller fats)
How does bile emulsify fats?
squeezes itself in between fat droplets to separate them and make them smaller
Where does chemical digestion of carbohydrates occur?
mouth, stomach, small intestine
When does the digestion of lipids start and end?
start small intestine (duodenum), end small intestine (duodenum
When does the digestion of carbohydrates start and end?
start mouth, end small intestine (duodenum)
When does the digestion of proteins start and end?
start stomach, end small intestine (duodenum)
Result of chemical digestion for carbohydrates
monosaccharides
Result of chemical digestion for proteins
amino acids
Result of chemical digestion for lipids
glycerol and fatty acids
Salivary Amylase
enzyme that is secreted by the salivary glands and breaks down carbohydrates into monosaccharides
Pepsin
enzyme that is secreted by glands in the stomach that breaks down proteins into amino acids
Trypsin
enzyme that is secreted by the pancreas and enters the small intestine that breaks down proteins into amino acids
Lipase
enzyme that is secreted and released by the pancreas and enters the small intestine and breaks down lipids into glycerol and fatty acids
Pancreatic Amylase
enzyme released by the pancreas into the small intestine to break down carbohydrates into monosaccharides
What muscle types are used in the digestive system?
smooth muscle and skeletal muscle
What part of the digestive system uses skeletal muscles?
the mouth
What part of the digestive system uses smooth muscles?
the rest of the digestive system that is not the mouth
Peristalsis
contractions of smooth muscle
What does peristalsis have to do with the digestive system?
The esophagus is made up of smooth muscle. Peristalsis occurs which creates enough force for food to go toward the stomach
Function of rectum
stores undigested food/waste for later excretion through the anus
Nutrition
process by which the body obtains raw materials for food
Nutrients
the source of raw materials that the body uses to build tissues and provide energy for cellular work
Essential Nutrients
nutrients that must be supplied in diet because the body cannot make them
Organic Nutrients
carbs, proteins, lipids (fats), vitamins
Vitamins are sometimes called…?
coenzymes because they help out actual enzymes do their job
Inorganic Nutrients
water and minerals
Bolus
chewed clump of food that leaves the mouth
Chyme
bolus that has turned into an acidic liquid (oatmeal-like) in the stomach
Epiglottis
flap that covers the trachea (windpipe) when food moves from the pharynx to the esophagus
Gastric Juice
“stomach juice” is a mixture of mucus, hydrochloric acid, and pepsin
Which part of the small intestine do secretions from the pancreas and gallbladder enter?
duodenum
Villi
finger-like projections in the small intestine
Purpose of Villi
to increase the surface area for absorption of food
What neutralizes stomach acid before food enters the small intestine?
sodium bicarbonate (a base) produced by the pancreas
Organs involved in absorption
small intestine, large intestine (water only)
