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71 Cards in this Set
- Front
- Back
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Nutrient
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any substance consumed by an animal that is needed for survival, growth, development, tissue repair, or reproduction
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Do nutrients need to be digested
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sometimes
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Absorption
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small molecules transported from digestive cavity to animal’s circulatory system
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5 categories of organic(carbon-based) nutrients
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Carbohydrates
Proteins Lipids Nucleic acids Vitamins |
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Essential
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body cannot produce on its own
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4 groups of essential nutrients
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Essential amino acids
Essential fatty acids (“good fats”) Minerals Vitamins |
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Good Fats
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Omega-3 fatty acids are a family of polyunsaturated fatty acid (PUFA), which have three or more double bonds. Omega-3 fatty acids are found in foods such as walnuts, canola oil, marine cold water fish and fish oils.
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Bad Fats
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Examples of foods containing a high proportion of saturated fat include dairy products (especially cream and cheese but also butter and ghee), animal fats such as suet, tallow, lard and fatty meat, coconut oil, cottonseed oil, palm kernel oil, chocolate.
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Good Fats
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Omega-3 fatty acids are a family of polyunsaturated fatty acid (PUFA), which have three or more double bonds. Omega-3 fatty acids are found in foods such as walnuts, canola oil, marine cold water fish and fish oils.
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Bad Fats
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Examples of foods containing a high proportion of saturated fat include dairy products (especially cream and cheese but also butter and ghee), animal fats such as suet, tallow, lard and fatty meat, coconut oil, cottonseed oil, palm kernel oil, chocolate.
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Can Essential amino acids be synthesized by animal's cells
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no
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Are essential amino acids stored
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no
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How do carnivores and omnivores obtain them
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Eating meat
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Essential fatty acids
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Certain polyunsaturated fatty acids that cannot be synthesized by animal cells
Unsaturated fatty acids found primarily in plants Strict carnivores obtain them from fish or adipose tissue of birds and mammals |
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Minerals
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Inorganic (= not carbon based) ions
Many required in only trace amounts Less than 1 mg/day Some minerals can be stored (calcium) Not all minerals used at the same rate or in the same way |
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Vitamins
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Important organic nutrients that serve as coenzymes
Fat-soluble vitamins – vitamin A – stored in adipose tissue Water-soluble vitamins – vitamin C – not stored Not all animals require the same vitamins Only primates and guinea pigs can’t synthesize vitamin C |
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What is scurvy caused by
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vitamin c deficiency
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Heterotrophs
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Use organic carbon for growth
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Autotrophs
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Use inorganic carbon for growth
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Heterotrophs
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Use organic carbon for growth
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Autotrophs
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Use inorganic carbon for growth
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How do suspension feeders get food
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They filter organic material from the water
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What does digestion require
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enzymes capable of hydrolyzing bonds
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Intracellular digestion
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Only in some very simple invertebrates (sponges and some single-celled organisms)
Only tiny bits can be phagocytosed at one time No mechanism for storing food |
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Extracellular digestion
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In a cavity
Protects interior of cells from hydrolytic enzymes Can consume large food |
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Gastrovascular cavity
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Simple extracellular digestion
One opening is entry and exit Digestion and distribution of nutrients Food particles eventually phagocytosed |
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Alimentary canal or gastrointestinal (GI) tract
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May include tongue, teeth, salivary glands, liver, gallbladder, and pancreas
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Alimentary canal
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Single elongated tube with entry and exit ends
Lined by epithelial cells Synthesize and secrete digestive enzymes Secrete hormones Transport of digested material Several specialized regions Different environments for different processes Storage area |
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What must be absorbed b the epithelial cells lining the alimentary canal?
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Nutrients
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How may Nutrients be absorbed by the epithelial cells lining the alimentary canal
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Passive diffusion
Facilitated diffusion Active transport |
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Where are the nutrients absorbed by the alimentary canal transported
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To the blood
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Functional Regions
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Anterior end functions primarily in ingeston
Middle portion functions in storage and initial digestion Upper part of small intestine and associated organs(liver, gallbladder, pancreas) = main digestion |
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Saliva
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Moisten and lubricate food to facilitate swallowing
Dissolve food particles to facilitate taste Kill ingested bacteria |
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Pharynx and esophagus
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pathway only.
Swallowing begins in the esophagus as voluntary action. Action continues by involuntary peristalsis. |
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Crop
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for storage and softening
Found in birds and many invertebrates |
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Where does digestion begin?
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In the mouth
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Stomach
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saclike organ evolved for storing food.
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What does the stomach partially digest?
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Proteins
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What regulates the rate of emptying into small intestine?
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stomach
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What do glands secrete?
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Hydrochloric acid – kills microbes, dissolves particulate matter
Pepsinogen – converted to pepsin to begin protein digestion (cleaves peptide/carbon bonds) No lipid or carbohydrate digestion Food reduced to chyme |
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Bird Stomach
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Proventriculus secretes acid and pepsinogen
Gizzard grinds food using sand or small stones Takes the place of teeth as an adaptation to flight |
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Herbivores must digest cellulose but lack what
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Cellulase
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What fo Herbivores rely on to digest cellulose into monosaccharides
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Microbes
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What fo Herbivores rely on to digest cellulose into monosaccharides
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Microbes
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Simple stomach
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Uses cecum at connection between small and large intestine
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Complex stomach
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Has several chambers
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Forestomach
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3 lower esophageal pouches
Rumen and reticulum – contain cellulose digesting microbes Omasum – absorbs some of the water and salts from food |
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Cud
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occasionally regurgitated, rechewed and swallowed
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Abomasum
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true stomach – eventually food, microbes and by-products of microbial digestion
Contains acid and enzymes |
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Small intestine
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Nearly all of food and absorption of food and water occur in the first quarter.
Hydrolytic enzymes found on luminal surface or secreted by pancreas into lumen Products of digestion absorbed across epithelial cells and enter circulation Vitamins, mineral and water also absorbed |
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Villi
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Finger-like prjection used to increase surface area
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Epithelial cells
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Covered with microvilli creating bush border
Increases surface area 600 fold Increases likelihood of encountering digestive enzyme and being absorbed |
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What does each villus contain
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Capillary – nutrients other than fat absorbed into blood
Lacteal (lymphatic vessel) – allows for larger fat particles to enter, eventually dumped into blood |
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Which have longer intestines herbivores or carnivores
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Herbivores, to digest plant material
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Pancreas
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Secretes digestive enzymes and bicarbonate ion rich fluid
Bicarbonate neutralized acidic stomach chyme as it enters small intestine |
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Liver
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Site of bile production
Bile contains bicarbonate ions (neutralize acids), bile salts (solubilize fat) Bile stored in gallbladder |
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Large Intestines
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Primary function to store and concentrate fecal matter and absorb some salt and water
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What does bacteria produce
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Vitamins and flattus
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Cecum
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Chyme enters through sphincter
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Colon
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Ascending, transverse and descending
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Carbohydrates
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in omnivore: most are starch and cellulose with some monosaccharides and some disaccharides
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Mouth
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Starch digestion by salivary amylase
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Stomach
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additional starch digestion by pancreatic smylase
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Lactose intolerance
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Milk of all mammals contains lactose
Lactase digests lactose Once weaned, mammals never again drink milk, except for humans Developmental mechanism to turn off lactase not known 90% of world’s population can’t fully digest lactose after early childhood In Neolithic times, adults able to digest lactose enjoyed selective advantage and passed on their genes more frequently |
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Fat
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most in the form of triglycerides.
Digestion entirely in small intestine Phospholipids and bile salts emulsify fat into small droplets with increased surface area for igestion Bile salts form micelles allow lipids to diffuse into intestinal cells Triglycerides reform inside intestinal cells. Enters into general blood circulation |
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Do vitamins minerals and water require digestion
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NO
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How are vitamins, minerals and water absorbed
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In their full form
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How are fat-soluble vitamins absorbed
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They follow pathway for fat absorption
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Is water absorbed in the stomach
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Some but most in the small intestine
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What does the nervous system affect in the regulation of digestion?
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Control of muscular and glandular activity by local nerves in alimentary canal.
Long distance regulation by the brain |
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Hormones
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Secreted mainly by cells scattered throughout the epithelium of stomach and small intestine
Target cells in pancreas and gall bladdder |
