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75 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Undernourished |
- Diet is deficient in calories - Glycogen in liver and muscles -> fat from adipose tissues [where excess calories stored] -> breakdown of own proteins - -> Atrophy, consumption of brain proteins |
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Essential nutrients |
- Chemicals an animal requires but cannot synthesize - AA, FA, vitamins, minerals
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Four aspects |
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Malnourished |
- Unbalanced diet, including excessive eating |
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Essential amino acids |
- human adults can only produce 12/20 amino acids needed to make proteins - kwashiorkor: unbalanced diet -> deficiency, humans cannot store excess AA |
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Essnetial fatty acids |
- unsaturated, e.g. linoleic acid -> phospholipids for membranes - most diets include sufficient quantities |
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Vitamins |
- req'd in much smaller quantities (0.01 to 100 mg/day) - may serve catalytic function in coenzymes - water-soluble: excess in urine - fat-soluble ADEK: excess stored as fat |
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Minerals |
- inorganic, may serve maintenance roles (Ca2+) or as parts of enzymes/other molecules (Cu, Fe) |
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Herbivores |
- eat autotrophic organisms - have teeth with broad, ridged surfaces for grinding vegetation |
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Carnivores |
- eat other animals - have pointed canines and incisors used to crush, shred, and tear away flesh |
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Omnivores |
- eat other animals and autotroph - have relatively unspecialized dentition |
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Ingestion |
- first stage of food processing - act of eating |
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Digestion |
- second stage of food processing - cleaves macromolecules into component monomers (polysacch -> simple sugars, proteins -> amino acids, fats + glycerol -> fatty acids) |
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Enzymatic hydrolysis |
- Hydrolytic enzymes catalyze digestion of macromolecules by adding water - Occurs in specialized compartment, preventing damage of animals' own cells |
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Absorption |
- third stage of food processing - uptake of small molecules |
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Elimination |
- fourth stage of food processing - undigested material passes out of digestive compartment |
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Suspension-feeders |
- Sift food particles from water - E.g. clams, oysters (trap food on gills), baleen whales (strain food from water) |
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Substrate-feeders |
- Live on or in food source and eat through - E.g. leaf miners |
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Deposit-feeders |
- Type of substrate-feeder that ingests partially decayed organic materials along with substrate - E.g. earthworms |
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Fluid-feeders |
- Suck nutrient-rich fluids from a living host - E.g. leeches; aphids ingest phloem from trees |
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Bulk-feeders |
- Eat relatively large pieces of food - Most animals -> kill prey or tear off vegetation |
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Intracellular digestion |
- Food vacuole: simplest digestive compartment - When hydrolytic enzymes are secreted into food vacuole and digestion occurs - Sponges: all digestion intracellular |
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Extracellular digestion |
- Occurs in continuous compartments - After some hydrolysis |
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Gastrovascular cavity |
- Digestive sac with a singular opening - Functions in both digestion and nutrient distribution - Possessed by most animals with a simple body plan |
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Complete digestive tract |
- Combination of extracellular and intracellular digestion that allows animals to feed on larger prey items - Phagocytosis: for microscopic foods - Possessed by animals more complex than cnidarians and platyhelminthes |
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Alimentary canal |
- Digestive tube running in between two openings: mouth and anus - Can be organized into specialized regions -> stepwise digestion and absorption for efficiency - Unidirectional |
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Peristalsis |
- Rhythmic smooth muscle contraction - Pushes food along tract |
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Sphincters |
- Modifications of the muscle layer into ringlike valves - Occur at some junctions between compartments - Regulate passage of materials through system |
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Salivary gland |
- Accessory gland |
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Pancreas |
- Accessory gland - Compound gland: exocrine produces hydrolytic enzymes and bicarbonate buffer to neutralize acid chyme - Endocrine produces and secretes hormones (insulin, glucagon) |
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Liver |
- Accessory gland - Produces bile |
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Gallblader |
- Accessory gland - Stores bile |
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Oral cavity |
- Where physical and chemical digestion begin - Chewing -> makes food easier to swallow, increases surface area for enzymes - Saliva: (1) mucin, protects mouth from abrasion and lubricates food (2) buffers that neutralize acids, (3) antibacterial agents (4) salivary amylase |
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Salivary amylase |
- Enzyme that hydrolyzes starch and glycogen -> maltose, small polysaccharides |
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Bolus |
- Formed by tongue as it tastes and manipulates food - Pushed back into oral cavity and pharynx |
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Pharynx |
- intersection of digestive and respiratory system |
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Epiglottis |
- Swallowing moves it to block entrance of trachea (glottis) - Directs food through pharynx, to esophagus |
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Esophagus |
- Muscular tube that conducts food from pharynx to stomach through peristalsis |
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Stomach |
- Large, saclike structure just below diaphragm that stores food and performs preliminary digestion - Has elastic wall with rugae: folds that can expand to accommodate up to 2L of food - Storage capacity permits periodic feeding |
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Gastric juice |
- Composed of HCl (secreted by parietal cells in stomach epithelium) and Pepsin - HCl provides acidity, which kills bacteria, denatures protein, and starts conversion of pepsinogen to pepsin |
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Pepsin |
- Splits peptide bonds next to some amino acids - Endopeptidase: only splits peptide bonds located within polypeptide chain |
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Pepsinogen |
- Secreted by chief cells in stonach epithelium - A zymogen (inactive protease), precursor to pepsin |
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Acid chyme |
- Nutrient broth - Result of churning and enzyme action |
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Pyloric sphincter |
- Regulates passive of acid chyme into small intestine - Located at bottom of sromach - Relaxes at intervals - Permits small quantities of chyme to pass |
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Small intestine |
- About 6m in length - Site of most enzymatic hydrolysis of food and andorption of nutrients |
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Duodenum |
- first 25 cm of small intestine - Where carbohydrate (C) digestion begins again, pancreatic amylases hydrolyze starch and glycogen into disaccharides - Each disaccharide has own disaccharidase - Final breakdown of carbohydrates occurs where sugars will be absorbed |
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Bile |
- Does not contain digestive enzymes - Contains bile salts which emulsify fat - Contains pigments that are byproducts of destroyed RBCs |
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Trypsin |
- Endopeptidse that catalyzes conversion of more trypsinogen to trypsin - Catalyzes conversion of other zymogens |
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Chymotrypsin |
- Endopeptidase - Digests large polysaccharides into shorter chains by breaking internal peptide bonds adjacent to certain amino acids - Converted from chymotrypsinogen by trypsin |
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Carboxypeptidase |
- Exopeptidase that splits amino acids, one at a time, off the end of a polypeptide with a free carboxyl group - Production looped by trypsin |
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Amimopeptidase |
- Protein-digesting enzyme secreted by lining of small intestine - Begins at the end of a polypeptide that has a free amino group - Splits off one amino acid at a time |
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Dipeptidase |
- Protein-digesting enzyme secreted by lining of small intestine - Splits small polypeptides |
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Enteropeptidase |
- Converts trypsinogen to trypsin in small intestine protein digestion (C -> P -> NA -> F) - Activates zymogens secreted by pancreas |
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Nucleases |
- Hydrolyze DNA and RNA into nucleotides during nucleic acid digestion (N) - Other hydrolytic enzymes (nucleotidases and nucleosidases) break nucleotides -> nucleosides, nitrogenous bases, sugars, phosphates |
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Emulsification |
- Occurs during fat digestion (F), exclusive to small intestine - Produces many small fat droplets that collectively have a large surface area exposed for digestion |
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Lipase |
- Secreted by pancreas into duodenum - During fat digestion (F), hydrolyzed gats into glucerol and fatty acids |
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Jejunum |
- Specialized for nutrient absorption |
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Ileum |
- Specialized for nutrient absorption |
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Villi |
- Projections from large folds in the walls - Increases surface area for absorption tk about 300m² |
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Microvilli |
- Microscopic projections from villi |
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Brush border |
- Microvillar surface - Exposed to lumen of intestine |
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Lacteal |
- Tiny lymph vessel - Along with capillaries, penetrate hollow core of each villus |
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Chylomicrons |
- Absorbed glycerol and fatty acids recombined in epithelial cells to form fats, that are coated with proteins - Enter lacteals |
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Hepatic portal vessel |
- Where capillaries and veins draining nutrients from villi converge - Leads directly to liver - Various organic molecules used, stored, or converted to different forms - Blood flows at a rate of 1L/min |
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Gastrin |
- Released from the stomach in response to presence of food - Stimulates gastric juice (HCl and pepsin) release from stomach - Stimulates mitosis and development of new mucosa cells |
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Secretin |
- Released from duodenum in response to acid chyme entering from stomach - Signals pancreas to release bicarbonate buffer to neutralize acid chyme |
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Cholecystokinin (CCK) |
- Released from duodenum in response to acid chyme entering from stomach - Signals gallbladder to release bile - Signals pancreas to release pancreatic enzymes into duodenum - May be involved with satiety reflex of brain |
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Enterogastrone |
- Released from duodenum in response to presence of far in chyme - Inhibits peristalsis in stomach - Slows digestion |
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Large intestine |
- Connects to small intestine at a T-shaped junction containing a sphincter |
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Colon |
- Around 1.5 m long - Inverted U - Water reabsorption |
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Cecum |
- Blind end of T in large intestine |
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Appendix |
- Fingerlike extension of cecum composed of lymphoid tissue |
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Feces |
- Wastes of digestive tract - Moved through colon through peristalsis - Intestinal bacteria live on organic material in feces, and some produce Vit. K absorbed by host - May contain an abundance of salts |
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Rectum |
- Stores feces - Has involuntary sphincter |
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Ruminant |
- Organism with elaborate alimentary canal structure - Swallows food then brings it back up to keep chewing - E.g. cow, sheep |
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Anus |
- Has voluntary sphincter - For feces elimination |
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