Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
37 Cards in this Set
- Front
- Back
disgestion
|
the process that physically and chemically breaks down food
|
|
digestive systems
|
-take in food and break complex molecules into simpler forms that can be absorbed
-material that cannot be absorbed is expelled |
|
ruminant animals
|
-herbivores that are able to break down cellulose and extract nutrients from tough plant matter
-Have elaborate digestive systems that house microorganisms which break down cellulose (using cellulase enzymes) |
|
rumination
|
regurgitate and rechew food (cud)
|
|
intestinal length is...
|
-correlated with diet
-because cell walls are difficult to digest, herbivore intestines are long to allow more time for nutrient absorption -carnivore intestines are relatively short because proteins are easy to digest |
|
incisors used for
|
biting
|
|
canines used for
|
tearing
|
|
premolars used for
|
grinding
|
|
molars used for
|
crushing and chewing
|
|
crop
|
stores and moistens food
|
|
stomach
|
secretes enzymes
|
|
gizzard
|
muscular with a hard lining for grinding food (birds)
|
|
small intestine
|
further digestion and absorption
|
|
functions of saliva
|
-contains amylase: breaks down starches into sugars
-contains bacteria-killing enzymes and antibodies -lubricates food: helps with swallowing -carries food molecules to taste buds on tongue for food quality identification |
|
stomach
|
disrupts food, begins protein digestion
|
|
small intestine
|
most digestion and absorption occurs here
|
|
rectum
|
stores feces
|
|
salivary glands
|
secrete lubricating fluid and starch-digesting enzymes
|
|
pharynx
|
shared digestive and respiratory passage
|
|
epiglottis
|
directs food down the esophagus
|
|
esophagus
|
transports food to the stomache
|
|
gallbladder
|
concentrates, stores bile from liver
|
|
pancreas
|
secretes buffers, several digestive enzymes (also an endocrine organ)
|
|
large intestine
|
absorbs water, houses bacteria, produces feces
|
|
appendix
|
no human function
|
|
oral cavity, tongue, teeth
|
grind food, mix with saliva
|
|
esophagus
|
-Swallowing forces food into a muscular tube called the esophagus
-The esophagus forms waves of muscular contraction (peristalsis) that carry food to the stomach |
|
stomach
|
-is an expandable muscular sac
-connects to the small intestine, but the pyloric sphincter muscle keeps food from entering it |
|
3 major functions of the stomach
|
-food storage and gradual release into the small intestine
-mechanical food breakdown by using churning contractions -chemical food breakdown by stomach gland secretions |
|
food in the stomach is gradually turned into
|
chyme (a mixture of partially digested food and stomach secretions)
|
|
peristaltic waves
|
propel food toward small intestine
|
|
pyloric sphincter
|
opens and lets chyme enter small intestine in small amounts
|
|
small intestine
|
-Most digestion occurs in the small intestine
-The small intestine is a narrow tube about 10 feet long -Most absorption occurs in the small intestine -The small intestine is well adapted for absorption of nutrients -Has numerous folds with fingerlike projections (villi) on its surface to increase absorptive surface area -Each villus cell has many microvilli that increase surface area even more |
|
Food is digested and absorbed with the aid of digestive secretions from three sources:
|
-liver
-pancreas -cells of the small intestine |
|
2 parts of large intestine:
|
-Colon: most of its length
-Rectum: the terminal compartment |
|
large intestine
|
-about 5 feet long and three inches wide
-a mix of water, undigested nutrients, and fiber enters the large intestine -the large intestine contains bacteria that consume unabsorbed nutrients and synthesize vitamins -the large intestine absorbs vitamins, leftover water, and salts |
|
digestion is controlled by
|
-the nervous system and hormones
-Nervous control of digestion Nervous system responds to sensory input, such as sight, smell, and taste |