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77 Cards in this Set
- Front
- Back
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Heterotroph
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Organism that obtains organic food molecules byeating other organisms
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Autotroph |
Organism that uses solar energy or inorganic chemical energy to synthesize its own organic molecules |
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Kilocalorie (kcal)
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Unit of energy for metabolism
1 kcal =1,000 calories = 1 Calorie |
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Calorie (Cal)
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=1000 calories=1 kcal
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Metabolic rate
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Total energy expenditure per unit of time
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Carbon skeleton
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-Building blocks for larger organic molecules
-Acetyl CH3CO- group obtained from food to build more complex molecules |
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Essential amino acids
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-Cannot be synthesized by an animal, must be obtained via food
-Human adults have 8 |
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Complementary diet
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A diet of Grain and Legumes which are necessary in order to obtain all 8 essential amino acids
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Essential fatty acids |
Unsaturated fatty acids that animals cannot synthesize -Linoleic acid is one that helps to synthesize other unsaturated fatty acids including signaling molecules and membrane phospholipids |
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Macronutrients
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Mineral elements required in large amounts
-Calcium ~.1g/day |
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Micronutrients
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Mineral elements required in small amounts
-Iron~15 mg/day |
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Vitamins
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-Carboncompoundsrequiredforgrowthandmetabolismthatcannotbesynthesized
-Function as coenzymes or parts of coenzymes |
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Malnutrition
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Nutrient deficiency
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Deficiency disease
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The result of chronic malnutrition
Eg: -Scurvy-Lack of Vitamin C -Berberi-Lack of B1 -Hypothyroidism-Lack of iodine -Pernicious anemia-Lack of B12 (production or absorption) |
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Predators
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Animals that eat other organisms
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Herbivores
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Prey on plants
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Carnivores
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Prey on animals
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Omnivores
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Prey on plants and animals
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Enamel |
Calcium phosphate that covers the crown of teeth |
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Dentine |
Bony material in crown and root of teeth |
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Pulp cavity
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Blood vessels, nerves and dentine producing cells in teeth
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Mouth
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Opening at end of tubular gut that takes in food
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Anus
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Opening at end of tubular gut that eliminates food
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Stomach
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Storage chambers for food that allow for gradual digestion to occur
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Intestine
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-Where digestive enzymes hydrolyze food molecules.
-Water, nutrients and ions absorb across the lining of the tube |
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Feces
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Undigested wastes
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Rectum
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Muscle that assists the anus in elimination of wastes
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Proteases
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Break bonds between adjacent amino acids in proteins
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Carbohydrases
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Hydrolyze carbohydrates
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Peptidases
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Hydrolyze small peptides
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Lipases
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Hydrolyze fats
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Nucleases
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Hydrolyze nucleic acids into component nucleotides
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Zymogen |
Digestive enzyme produced in an inactive form -Cannot act of the cells that produce it -Activated by another enzyme within the lumen of the GI tract |
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Lumen
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Gut cavity
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Mucosa |
-Layer of epithelial cells in vertebrate gut tissue -May secrete mucus, digestive enzymes, or hormones -May aid in absorption |
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Submucosa |
-Layer of epithelial cells in vertebrate gut tissue -Contains blood and lymph vessels and nerves |
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Enteric nervous system |
-Nerve nets in the submucosa and in between smooth muscle layers -Only from synapses with other nerves in the network -Responsible for communication with the gut -CNS can influence the system, but it is autonomous |
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Peritoneum
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-A membrane that surround the gut and lines the wall of the cavity
-Connective tissue including epithelial tissue that secretes lubricating fluids so organs can easily slide against one another |
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Esophagus
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Brings food from the mouth to the stomach
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Epiglottis
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Tissue covering the entrance to they larynx that keeps food out of the trachea
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Peristalsis
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Waves of muscle contractions that move food toward the stomach
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Sphincter |
A ring of circular smooth muscle that prevents food from moving backwards in the esophagus |
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Segmentation movements
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-Movements of the gut that periodically contract but do not generate a wave of contraction that moves food only in one direction
-Food can move in more than one direction |
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Gastric pits
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Contian 3 types of secretory cells in the stomach
1) Chief Cells 2) Parietal Cells 3) Epithelial cells |
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Chief cells
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Secrete pepsinogen, the zymogen(inactive form) of the protease pepsin
-Low pH of stomach converts it to the active form by removing a small portion exposing the active site -Pepsin can then activate other pepsinogen molecules |
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Autocatalysis
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A process by which the active form of a protease can activate the inactive form
E.g. Pepsin can activate Pepsinogen |
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Parietal cells
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Secretes HCL into the stomach to keep pH below 1
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Chyme |
A mixture of gastric juices and partly digested food in the stomach |
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Small intestine
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Where most chemical digestion occurs
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Duodenum
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Initial section of the small intestine and the site of the majority of digestion
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Jejunum
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One of two parts of the small intestine responsible for the majority of absorption
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Ileum
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One of two parts of the small intestine responsible for the majority of absorption
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Villi
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-Finger-like projections that are on the folds of the small intestine wall
-Increase surface area |
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Microvilli
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Smaller projections on the villi
-Further increase surface area giving the small intestine enormous surface area to absorb nutrients |
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Bile salts
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-Emulsify fats in chyme which enlarges the surface area of fat so that lipase digest fat
-Synthesized in the liver |
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Bile |
-Secreted by the liver and contains bile salts -Flows through the hepatic duct into the duodenum |
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Gallbladder
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Site of bile storage
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Cholecystokinin(CKK)
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-A hormone which stimulates the wall of the gallbladder to contract rhythmically and squeeze bile into the duodenum
-Fat entering the duodenum signals epithelial cells to release CKK |
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Micelles
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Formed by the lipophilic ends of bile salts merging with fat droplets
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Trypsin |
-In the duodenum, the active form of the protease trypsinogen which is activated b enterokinase -Activates other zymogens |
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Chylomicrons
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-Triglycerides and cholesterol that are coated with proteins so that they are water soluble
-Pass into lacteals |
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Lacteals
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Vessels of the lymph system that carry chylomicrons
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Hepatic portal vein
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A system of veins leaving the digestive tract that goes to the liver with nutrients
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Colon
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-The large intestine
-Produces feces -Absorbes water and ions -Too much water -> Constipation -Too little water -> Diarrhea |
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Secretin
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-From the duodenum
-Causes pancreas to secrete bicarbonate |
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Gastrin
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Released by he stomach, stimulating stomach movements and secretion of digestive juices
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Absorptive state |
-The period after a meal when food is in the gut and nutrients are absorbed -Blood glucose levels rise -Insulin release promotes uptake/utilization of glucose for metabolic activities or synthesis of fat or glycogen |
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Postabsorptive state
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-The period when the stomach and small intestine are empty and metabolism runs on internal reserves
-Blood glucose levels fall -Insulin release decreased -> glucose absorption slowed -Most cells switch to folic acid for fuel -Glucagon release promotes glycogenoloysis and gluconeogenesis |
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Lipoprotein
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-Core of hydrophobic fat and cholesterol covered with hydrophilic proteins so they can be transported int he blood
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High-density lipoprotein
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Removes cholesterol form tissues and carries it to the liver
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Low-density lipoprotein
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Transports cholesterol in the body
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Very low-density lipoprotein |
Transports triglycerides to fat cells |
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Arcuate nucleus |
-Hormones act on the arcuate nucleus and send signals to two areas of the brain: 1) suppress eating area 2) stimulate eating area -insulin and leptin activate the suppress area and inhibit the stimulate area -ghrelin activates the stimulate area and inhibits the suppress area |
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Leptin
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-A hormone released by fat cells in proportion to how much lipid they contain
-Provides feedback to the brain on the status of the body's fat reserves |
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Ghrelin
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A hormone secreted by the stomach when it is empty promoting hunger
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What are water soluble vitamins? |
-B Complex and C -Excess is eliminated in urine |
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What are fat soluble vitamins? |
-A, D, E, K
-Can accumulate to toxic levels in body fat and liver |
