Nutrition and Digestion Flashcards
What are the dietary modes?
Carnivores: eat other animals
Herbivores: eat autotrophs (plants)
Omnivores: eat both animals and plants
Detritivores: eat dead/decaying matter
What type of eaters are most animals?
opportunistic
What must diet satisfy for?
energy, atoms (carbon and nitrogen), and essential nutrients
What are essential nutrients?
cannot be made by cells, but needed for life essential amino acids essential fatty acids vitamins minerals
What is undernourishment?
diet provides less energy than needed for maintenance of body and functions (starvation)
What is malnourishment?
long-term lack of one or more essential nutrients from the diet, leading to deformity/disease
What are the four stages of food processing?
ingestion, digestion, absorption, and elimination
What are the four types of feeders?
suspension (filter): pushing, sucking, flowing water through structures
substrate: live on or in their food source
fluid: often parasites that suck nutrient rick liquids
bulk: have jaws and test to eat large chunks and are swallowed
Describe test in mammals/vertebrates.
types of dentition based diet species has adapted to
teeth vary in size, shape, and cutting surface
vary in number of different types
What is digestion?
breaking down food into molecules small enough to later absorb
What is mechanical digestion?
chewing breaks food into smaller pieces
What is chemical digestion?
enzymatic hydrolysis splits molecule bonds
What is intracellular digestion?
endocytosis into cells occurs before complete digestion
lysosomes fuse and form food vacuoles where particles are further broken down
What is extracellular digestion?
completely digest food before absorption into cells
most animals do this though a simple gastrovascular cavity or complex alimentary canal
What is the first stage of extracellular digestion?
mechanical digestion in the oral cavity through chewing
salivary glands begin chemical digestion with Amylase to lubricate food
tongue forms a bolus of food for swallowing
What is the pharynx?
mammals have a junction between both the esophagus and windpipe (trachea) to the lungs
How does swallowing occur?
sphincter releases that causes the epiglottis to block the trachea
bolus is move to the stomach via peristalsis from smooth muscle
What is gastric juice?
hydrochloric acid: break up ECM and denature proteins
Pepsin: when large cellular components are exposed so proteins are digested into amino acids
What are the three cell types of the gastric gland?
parietal cells: secrete H+ and Cl- into stomach
chief cells: secrete pepsinogen which becomes pepsin when mixed with HCl
mucous cells: secrete mucous to protect lining from gastric juice
What are the three divisions of the small intestine?
duodenum
jejunum
ileum
Describe the duodenum.
entry point for digestive enzymes
most digestion occurs here
makes its own digestive enzymes from the epithelial lining
What is the pancreas?
sends lipases, proteases, and nuclease to breakdown fats, proteins, and nucleic acids
What is the liver?
makes bile salts, which are first stored in the gallbladder, and are used to breakdown fats
What part of small intestine perform the most absorption?
jejunum and ileum
