Digestive System Flashcards
Digestive system
System of organs responsible for breaking down food molecules and absorbing nutrients
Digestion
Process of breaking down food into molecules that can be absorbed and used by the body
Nutrients
Molecules that must be absorbed for body to function properly
Alimentary canal
Long winding tract that begins at mouth and extends to anus
30 ft long
Absorption
Transport of digested nutrients from digestive to circulatory system
Mouth
Site of ingestion
Ingestion
Process of taking in food molecules
What does the mouth specialize in?
Digestion of carbohydrates
Saliva
Activates taste buds
Lubricates food
Uses enzymes to digest foods (mainly carbs)
Amylase
Enzyme in saliva that breaks down starches (carbs) into smaller polysaccharide chains
Chemical digestion
Digestion using enzymes
Mechanical digestion
Digestion that occurs due to movement of tissue
Primary site for mechanical digestion
Mouth
Performed by teeth
Esophagus
Responsible for transporting food from mouth to stomach
Peristalsis
Use of muscle contractions to move food
Sphincters
Specialized muscles that restrict movement of food/fluid
Cardiac sphincter
Sphincter at bottom of esophagus
Controls how much food enters stomach
Stomach
Primary site of food storage
What does the stomach specialize in the digestion of?
Proteins
What cells does the lining of the stomach contain?
Parietal cells
Peptic cells
Parietal cells
Produce Hydrochloric acid (stomach acid)
Peptic cells
Release enzyme called pepsinogen
What happens to pepsinogen once activated in stomach?
Turns into pepsin
Pepsin
Breaks down proteins into short polypeptide chains
Ulcer
Site where stomach breaks down and is exposed to HCL
Plyoric sphincter
At bottom of stomach
Controls how much digested food leaves stomach
Small intestine
Primary site of absorption and digestion of lipids
3 sections of small intestine
Duodenum
Jejunum
Ileum
Duodenum
Short section after pyloric sphincter that wraps around pancreas
Pancreas
Primary site of enzyme production in digestive system
Peptidases
Pancreatic enzymes that specialize in breaking down polypeptide chains into smaller chains
Ex. Trypsin
Disaccharases
Break down short carb chains into single monosaccharides
Ex. Lactase
Lipase
Break down lipids into fatty acids and glycerol
Emulsification
Process of breaking down fat globules
Liver
Produces substance called bile
Where is bile stored?
Gall bladder
Bile
Emulsifies ingested lipids; released into duodenum
Why is duodenum different PH than stomach acid
Blood vessels along duodenum pump bicarbonate ions into HCL, causing neutralization reaction
Jejunum
Primary site of nutrient absorption
Lined with tube-like structures called villi
Villi
Shaped like thin tubes along intestinal wall to maximize surface area
Nutrients are absorbed into villi then into bloodstream
What do access monosaccharides get stored in the liver cells as?
Glycogen
Ileum
Re absorbs substances necessary for digestion (enzymes, bile, vitamins)
Ileocecal valve
Controls passage of fluid from small to large intestine
Large intestine (colon)
Final major organ of digestive system
Re absorbs water that enters from ileum
Home to the gut microbiome
Diarrhea
When waste passes to quickly through large intestine and water is not absorbed
Colonic bacteria
Bacteria from microbiome living in large intestine
Vitamins created by colonic bacteria
Vitamin B12
Vitamin K
Riboflavin
Thiamine
Rectum
Stored solid waste material (feces)
Final sphincter of alimentary canal
Anal sphincter (anus)
