Lesson Eight Flashcards
Digestion
Includes both physical and chemical processes that reduce food to small soluble molecules that can be absorbed
Certain substances that can be absorbed
- amino acids of proteins
- sugars of carbohydrates
- glycerol and fatty acids of fats
- some minerals and water
Oral cavity
Storage place for food while it’s being chewed, where saliva mixes with food
Salivary glands
Produce saliva for moistening and chemically digesting food. Saliva contains the enzyme salivary amylase which begins the chemical digestion of starch to maltose
Pharynx
Where oral and nasal cavities join, this is where swallowing occurs
Epiglottis
Flap of tissue, which closes off the trachea, keeping food from entering the air passage
Esophagus
Tube leading from pharynx to stomach.
Swallowing
Reflex action normally performed automatically. Food enters esophagus because air passages are blocked. The opening to the nose is covered by the soft palate. No breathing occurs or choking may occur
Peristalsis
Rhythmical contraction of the esophageal wall pushing food along. Also occurs along the intestinal tract. Smooth muscle cause contraction.
Cardiac (esophageal) sphincter
Band of muscle that closes off top part of stomach
Stomach
Stores and churns food to chemically and physically digest it. Chemical digestion of proteins begins here
Gastrin
Hormone produced by lower part of the stomach which enters blood stream to later stimulate gastric glands to produce pepsinogen and HCl. They react together and produces pepsin. Pepsin digests proteins to peptides
How does the gut protect itself from HCl and what is it called if it does fail itself?
It produces a mucous layer. If a portion of the gut is burned it is an ulcer.
Pyloric sphincter
Band of muscle which closes off the lower part of the stomach and only allows small amounts of chyme to enter the small intestine
Duodenum
First 10 inches of small intestine. Enzymes from both the pancreas and the small intestine digest all 3 food groups here. Bile also is secreted in the small intestine to emulsify fat
Pancreas
Produces enzymes and sodium bicarbonate (bicarbonate neutralized the acidic chyme to bring it to a pH if 8.5)
Gall bladder
Stores bile which is secreted into small intestine
Liver
Produces bile to emulsify fats which is then stored in the gall bladder
Small intestine
Final digestion and absorption of nutrients through the villi
The duodenal wall produces….
Secretin and CCK (cholocytokinin) in response to the prescience or acidic chyme
What does secretin do?
Stimulates the releases of pancreatic juices from the pancreas. Also stimulates the release of bile from the gall bladder
Small intestine is how long?
7m- first 10” are the duodenum
Duodenum has what secreted into it?
Sodium bicarbonate
Pancreatic amylase
Trypsin
Lupase
Small intestine enzymes
Peptidase
Maltose
Main function of the small intestine
Absorption of nutrient molecules (AA, glucose, fatty acids, and glycerol). Other disaccharides are digested in small intestine by their own enzymes (lactase aids in lactose digestion)
What makes the small intestine good for absorption?
Convoluted walls, and has vili (which have microvili)
Within each villus are
Blood vessels, and small lymph vessels called a lacteal which absorbs fluids and returns it to the veins later on.
Absorption occurs across the walls of each Villus by….
Active transport: glucose and amino acids enter the blood vessels and travel to the liver. Glycerol and fatty acids enter the lacteals
Appendix
Found at junction of small intestine and large intestine. Unknown function.
Large intestine
Absorption of water from undigested food, contains e.coli. E.coli produce some essential substances for the body. E.coli helps metabolize what we cannot.
Rectum
Enlarged portion of colon where undigested food it stored temporarily
Anal sphincter (anus)
Bands of muscle which allow undigested wastes to exit the body
Salivary amylase
Made in Salivary glands, acts in mouth, 7, acts upon starch to produce maltose
Pepsin
Made in stomach, acts in stomach, 3.5, acts upon proteins to produce peptides
Pancreatic amylase
Made in pancreas, acts in small intestine, 7.5, acts upon starch produces maltose
Trypsin
Made in pancreas, acts in small intestine, 7.5, acts upon proteins, produces peptides
Lipase
Produces in pancreas, acts in small intestine, 7.5, acts upon fat droplets, produces glycerol and fatty acids
Nuclease
Produced in pancreas and small intestine, acts in small intestine, 7.5, acts upon nucleic acids (DNA RNA) to produce nucleotides
Peptidases
Produced in small intestine, acts in small intestine, 7.5, acts upon peptides, produces amino acids
Maltase
Produced in small intestine, acts in small intestine, 7.5, acts upon maltose, to produce glucose
Nucleosidases
Produced in small intestine, acts in small intestine, 7.5, acts upon nucleotides, produces base, sugar, phosphate
Insulin
Hormone, produced by pancreas, secreted when high blood sugar, causes liver and muscles to take up and store excess glucose as glycogen. Promotes synthesis of proteins and fats, LOWERS BLOOD SUGAR
Glucagon
Pancreatic hormone, secreted when blood sugar low, causes liver and muscles to break down glycogen to glucose, stops protein and fat synthesis, raises blood sugar level
Exocrine
Produces some enzyme substances
Endocrine
Produces hormone
Functions of liver
- destroys old RBC concerts hemoglobin to product in bile
- produces bile that is stored in gall bladder
- stores glucose as glycogen after eating and breaks down glycogen to glucose between eating to remain glucose concentration.
- produced urea(from breakdown of AA)
- Makes blood proteins from AA
- detoxifies the blood by removing poisonous substances and metabolizing them
