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37 terms

Chapter 21- Nutrition and Digestion

STUDY
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ingestion
-eating food
digestion
-breaking down food into small molecules
-mechincal vs. chemical digestion
absorption
-taking up the products of digestion by cells lining the digestive system
-nutrients then move to the circulatory system
elimination
-releasing undigested material
alimentary canal
-complete digestive tract- tube from mouth to anus
accesory glands
-secrete digestive juices through ducts
-salivary glands, liver, gallbladder, pancreas
peristalsis
-alternating waves of contraction and relaxation of smooth muscle
-involuntary
-moves through esophagus and intestines
sphincter
-regulates movement through parts of the digestive system
-ring-like band of muscle
-esophagus, stomach, rectum
oral cavity
-teeth, tongue, salivary glands
-mechanical and chemical digestion
saliva
-protects soft lining of the mouth and lubricates food
-buffers= neutralizes food acids and prevents tooth decay
-antibacterial agents= kill bacteria
-amylase= digestive enzyme, starch
pharynx
-area in throat, openings to esophagus and trachea
esophagus
-muscular tube, food from pharynx to stomach
-muscles at top= voluntary
-muscles at bottom= involuntary
stomach
-stores food:
has many folds so it can stretch
can hold up to 2 liters of food/drink
-chemical digestion
sphincter
-muscular rings that regulate the passage of food
cardiac sphincter
esophagus to stomach
pyloric sphincter
stomach to small intestine
gastric juices
-protein digesting enzyme, mucus, and strong acid
pepsin
chemically digests proteins
gastrin
hormone that stimulate the secretion of gastric juice
small intestine
-finishes digeting large molecules and absorbs nutrients
-6 meters long
duodenum
-first 25 cm of the small intestine
-material from the stomach mixes with digestive juices
pancreas
produces pancreatic juice
-enzymes= breaks down complex sugars
-buffer= neutralize acid from stomach
liver
produces bile
-bile salts= break up fats into droplets
-detoxies substances
gall bladder
stores bile
-hormone from duodenum= stimulates release of bile
small intestine
produces intestinal enzymes
-breaks down proteins and nucleic acids
villi
finger-like projections within the inner wall
microvilli
each villus has more tiny projections
-increases the surface area
large intestine
-A.K.A. the colon
-absorbs water
-forms feces
-absorbs vitamins B and K
cecum
where small and large intestines meet
appendix
extends from the cecum
-contains a mass of white blood cells
ATP
-body's energy currency (comes from glucose)
organic molecules
-building blocks to build the body's own molecules
-amino acids= proteins
essential nutrients
-nutrients you can't build for yourself
-4 types
essential fatty acids
-used to build cell membranes
-found in seeds, grains, veggies
essential amino acids
-20 different amino acids needed to build
-found in animal produce
vitamins
-organic nutrients, small quantity needed
minerals
-not organic, small quantities needed