Chapter 10.8: Digestive System

types of digestion

mechanial, chemical

which organs use enzymatic digestion in the digestive system

mouth, stomach, small intestine

which organs use absorption in the digestive system

large intestine

what does the small intestine absorb

nutrients (carbs, proteins, fats, minerals, vitamins, water, salt)

what does the large intestine absorb

vitamins, water, salts

what does the body use to chemically digest

salivary amylase

what does salivary amylase do in saliva

breaks down starch into simpler carbohydrates

when saliva lubricates food, what does it create

bolus

upon swallowing, where does the food enter

pharynx

what does the pharynx do with the food digested

separates to form trachea and esophagus

what blocks the opening to the trachea to prevent choking

epiglottis

where does the food continue after entering the pharynx

esophagus

how is the bolus pushed down

by peristalsis (rhythmic waves of contraction)

how does food enter the stomach

by cardiac sphincter

what does the stomach lining have

gastric glands

which cells produce mucus

mucous cells

mucous cells function

lubricates and protects stomach lining from acid

what does food entry cause the stomach to do

distend

what does distend do

signal G cells to release gastrin

what is the function of gastrin

stimulate parietal cells to release vv acidic gastric juice, stimulate chief cells

what is the purpose of gastrin’s function of stimulating chief cells

screte gastric lipase and pepsinogen

what does gastric lipase do

breaks down fats into fatty acid and glycerol

what is pepsinogen

zymogen (inactive enzyme precursor)

what does pepsinogen do

activates into pepsin in acid

what does pepsin do

cleaves peptide bonds

how does chyme exit to the small intestine

pyloric sphincter

what is chyme

acidic semi-digested food

what organ is responsible for 90% of total digestive absorption

small intestine

what does the small intestine consist of

duodenum, jejunum, ileum

what is the mnemonic for the parts of the small intestine

DJ Eye

what secretes mucus

goblet cells

why do goblet ceells secrete mucus

to protect epitelial lining from acidic chyme

what does chyme trigger the release of

secretin

what does chyme triggering the release of secretin stimulate

pancreas release basic bicarbonate ions into duodenum

how does the pancreas release basic bicarbonate ions (HCO3-)

by pancreatic duct

what do proteins and fats that enter the small intestine stimuatlee the small intestine to release

cholecystokinin (CCK)

what does cholecystokinin (CCK) do

slows gastric emptying, stimulating pancreas to release digestive enzymes and gallbladder to release bild into duodenum

what ions and digestive enzymes does the pancreas secrete into the duodenum

bicarbonate, pancreatic amylase, proteases

what does bicarbonate do

neutralizes acidity

what does pancreatic amylase do

breaks don starch

what does proteases do

convert proteins to amino acids, trypsin and chymotrypsin initially released as zymogens

what is secreted by the duodenum into its lumen

enteropeptidase

what does the enteropeptidase do

converts trypsinogen to trypsin and chymotrypsinogen to chymotrypsin

which organ produces bile

liver

which organ stores and concentrates bile

gallbladder

why is bile important

lipid absorption

how is food moved by to the jejunum and ileum for absorption

peristalsis

what connects the small intestine (ileum) to the large intestine (colon)

ileocecal sphincter

process of fat absorption

liver produces bile flowing to gallbladder to store bile, chyme in small intestine cause duodenum to secrete CCK stimulating bile release, bile secereted into duodenum and emulsifies fat, lipases digest fat absorbed by small intestine

what are villi made of

enterocytes

what are enterocytes lined with

microvilli

what does villi and microvilli do

increase surface area and absorption efficiency

what are crypts

invaginations in intestinal wall

what contains cells that secrete enzymes and produce new epithelial cells for the lining

crypts

what happens inside the villus

nutrients (glucose & AA) are absorbed into blood capillaries and fats into lacteals

what are lacteals

specialized lymphatic capillaries

in addition to bile production, what processes is the liver involved in

protein synthesis, urea synthesis, storage, hormone synthesis, detoxification, glucose and fat metabolism

what is the mnemonic for the processes is the liver involved in besides bile production

PUSH DoG

what does blood maintenance comprise of in the liver

filters and detoxifies blood coming from digestive system, detoxifies body by metabolizing chemicals and drugs, destroys erythrocytes and bacteria

what does blood maintenance in the liver destroying erythrocytes and bacteria do

breaks down hemoglobin from old RBCs into bilirubin excreted in bile

glucose metabolism processes in the liver

glycogenesis, glycogenolysis, gluconeogenesis

what is glycogenesis

converts excess glucose into glycogen for storage in liver

what is glycogenesis stimulated by

insulin

what is glycogenesis inhibited by

glucagon, epinephrine

what is glycogenolysis

breaks down glycogen to glucose for bodily use between meals

what is glycogenolysis stimulated by

glucagon, epinephrine

what is glycogenolysis inhibited by

insulin

what is gluconeogenesis

converts glycerol and amino acids into glucose when glycogen stores are depleted

what is gluconeogenesis stimulated by

glucagon, epinephrine

what is gluconeogenesis inhibited by

insulin

what does protein metabolism comprise of in the liver

synthesizes plasma proteins from amino acids, converts ammonia into urea for excretion

what type of amino acids that synthesize plasma proteins in protein metabolism of the liver

blood clotting factors

where does water and mineral absorption occur in the large intestine

cecum

what is the appendix

projection in cecum

what kind of structure is the appendix

vestigial structure

where is water absorption completed and hardens feces in the large intestine

colon

where is feces stored in the large intestine

rectum

where is expelled through in the large intestine

anus

what kind of bacteria are in the large intestine

obligate anaerobes

functions of the large intestine

water absorption, mineral absorption, vitamin production and absorption

what is the mutualistic relationship within the large intestine

bacteria produced absorb vitamins, metabolize bile acid, ferment fiber

what is a key indicator of the health of the microbiome in the body

bile acid metabolism

where is are digestive enzymes, trypsin and chymotrypsin, found in the body

pancreas

where is the digestive enzyme, pancreatic amylase, found in the body

pancreas

where is the digestive enzyme, salivary amylase, found in the body

mouth

where is the digestive enzyme, pepsin, found in the body

stomach

where is the digestive enzyme, gastric lipase, found in the body

stomach

where is the digestive enzyme, peptidase, found in the body

small intestine

where is the digestive enzyme, enteropeptidase, found in the body

small intestine

trypsin and chymotrypsin function

protein breakdown

pancreatic amylase function

starch breakdown

salivary amylase function

starch breakdown into disaccharides

pepsin function

protein breakdown into peptides

gastric lipase function

fat breakdown into fatty acids and glycerol

peptidase function

peptide breakdown unto amino acids

enteropeptidase function

activate trypsinogen to trypsin