function of the mouth
Site of ingestion, Food is chewed here. Enzymes begin to break it up
Ingestion
Intake of food
digestion
The process by which the body breaks down food into small nutrient molecules-proteins, carbs, nucleic acids, lipids
Absorption
The process by which nutrient molecules pass through the wall of the digestive system into the blood stream
where mechanical and chemical occurs in the digestive tract
the stomach (both), mouth(both), small intestine (chemical digestion)
assimilation
moving the nutrients from the bloodstream and storing + using them in tissue
Egestion
The removal of nonsoluble waste materials.
function of saliva
moisten food and forms bolus, starts chemical digestion, inhibits bacteria
function of epiglottis
seal off the windpipe during eating, so that food cannot enter lungs
function of esophagus
to carry food, liquids, and saliva from the mouth to the stomach
Compostion of gastric juice
water, mucus, pepsinogen, hydrochloric acid, gastrin
Gastrin
Digestive hormone that stimulates sustained secretion of gastric juice from the stomach
Secretin
A hormone secreted by the small intestine (duodenum) in response to low pH (e.g., from stomach acid). It promotes the release of bicarbonate from the pancreas to act as a buffer.
enterogastrone
a hormone secreted by the small intestine that decreases gastric secretions and motility, slows peristalsis can help with indigestion and helps digest fats
Cholecystokinin
An intestinal hormone that stimulates the gallbladder to release bile
what the stomach mostly digests
protein
chemical digestion
Process by which enzymes break down food into small molecules that the body can use
mechanical digestion
Physical breakdown of large pieces of food into smaller pieces
function of duodenum
Regulates stomach and gallbladder emptying in response to acidic chyme.
function of pancreas
produces enzymes that digest fats, proteins, carbohydrates and nucleic acid
pancreatic juice contains:
proteases, lipases, nucleases, pancreatic amylases, peptisades
endocrine gland
something is made but it stays within that creation space- glands that produce hormones (insulin and glucagon)
exocrine glands
makes something but it is released to somewhere else- glands that produce enzymes (enzymes in pancreatic juice)
functions of the liver
detox blood, lipid metabolism, carbohydrate metabolism,creates and secrete bile, turn glucose into glycogen
hormone that carries glucose to the bloodstream
insulin
lipid metabolism
stores triglycerides and produces cholesterol
emulsification of fats
breaking fats into small emulsion drops using bile salts
carbohydrate metabolism
changes glucose to glycogen, breaks glycogen down into glucose—glucose released into bloodstream via insulin
function of the gall bladder
stores bile
large intestine composed of:
caecum, appendix, colon, rectum
bile
A substance produced by the liver that breaks up fat particles.
bile salts
compounds in bile that aid in emulsification
Pepsin
Enzyme that breaks down proteins in the stomach
Amylase
Enzyme in saliva that breaks the chemical bonds in starches
Lipase
pancreatic enzyme necessary to digest fats
nuclease
DNA cutting enzyme
villi
Fingerlike extensions of the intestinal mucosa that increase the surface area for absorption
Parts of villi
microvilli, epitheleum, blood capillaries
cardiac sphincter
opening from the esophagus to the stomach
mechanical digestion in the stomach
peristalsis
Peristalsis
Involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system.
Most digestion occurs in the
duodenum, pancreas, gall bladder
2 transport systems of villi
blood vessels- simple sugars, amino acids, vitamins, minerals
lacteals- lymph fluid
lacteals
contains lymph: helps absorb fat and fat soluble substances
body cannot not absorb:
cellulose, dead cells, bacteria, undigested food
the _______ __ of _______ in the colon helps trigger the _________ _________ which initiate bowel movement
build up, waste, nerve impulses
what is absorbed in the colon
water, salts, and vitamins
hormonal control
When food passes the cardiac sphincter, gastrin (a hormone) is released from the stomach wall and it travels via bloodstream to the gastric glands causing secretions.
Nervous control
sight, smell, or taste triggers a reflex which causes hormones to start secretions from gastric glands in the stomach.