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32 Cards in this Set
- Front
- Back
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What is negative feedback?
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A method of maintaining homeostasis:
- receptor detects change in conditions - integrator (often the brain) evaluates change - effector initiated by integrator |
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Ectotherms
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Obtain body heat from their environment
AKA poikilotherms |
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Endotherms
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Generate their own body heat
AKA homeotherms |
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Four types of respiration
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1 - Direct with environment
(Annelids, Platyhelminthes) 2 - Gills: evaginated structures, use countercurrent exchange (Annelids, fish) 3 - Tracheae: oxygen enters through spiracles, diffuses out of moist ends (Insects) 4 - Lungs: invaginated structures |
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Open circulatory systems
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- blood pumped into cavity called
hemocoel - oxygen and nutrient rich fluid called hemolymph bathes cells - hemolymph returns to heart through ostia |
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Path of blood through heart
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1 - deoxygenated blood enters through
two vena cava into right atrium 2 - blood moves through right AV valve into right ventricle; blood pumped to pulmonary artery through pulmonary semilunar valve 3 - oxygenated blood goes to left atrium through pulmonary veins 4 - blood passes through left AV valve into left ventricle; pumped into aorta through aortic semilunar valve |
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Maintenance of the cardiac cycle
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- regulated by autorhythmic cells
- three steps: 1 - SA node contracts both atria, sends delayed impulse to AV node 2 - AV node sends impules to bundle of His, which branches into Purkinje fibers; both ventricles contract 3 - when ventricles contract (systole) blood goes thru pulmonary arteries and aorta, AV valves close; when ventricles relax (diastole), semilunar valves close |
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Red blood cells
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- erythrocytes
- transport oxygen - catalyze conversion of CO2 and H2O to HCO3 + H+ |
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White blood cells
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- leukocytes
- five major groups of disease-fighting cells |
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Platelets
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- involved in blood clotting
- convert inactive fibrinogen to active fibrin |
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Plasma
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- liquid portion of blood
- bulk flow of CO2 takes place in it |
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Flame cells
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- found in platyhelminthes, like
planaria - body fluids moved by cilia through tube system - wastes excreted through pores |
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Nephridia
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- found in pairs in most annelids
- interstitial fluids enter through ciliated nephrostome - fluids concentrated as they go through collecting tubule - waste goes out through excretory pore |
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Malpighian tubules
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- arthropods
- attach to midgut, body fluids from hemolymph collect - materials retained pass through walls of midgut as other fluids go on - excreted through anus |
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Structure of nephridia
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1 - Bowman's capsule- bulb-shaped body,
branch of renal artery enters, branches into dense capillary structure called glomerulus 2 - Convoluted tubule- winding tube; proximal c.t. at Bowman's capsule, distal c.t. joins at collecting duct; in the middle, forms loop of Henle, surrounded by capillaries 3 - collecting duct - empties into renal pelvis |
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Operation of human nephron
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1 - Filtration - pressure forces water
and small solute (glucose, salts, nitrogen waste) into Bowman's capsule, which will go to c.t. 2 - Secretion - as filtrate goes thru proximal and distal c.t., extra fluid is selectively secreted 3 - Reabsorption - H20 is reabsorbed, salts join interstitial fluids, which are concentrated as they exit |
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Hormones involved in urine salt regulation
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1 - Antidiruetic hormone (ADH)-
increases reabsorption of water and concen. of salt in urine by increasing permeability of duct to water 2 - Aldosterone- increases reabsorption of water and salt; increases permeability of distal c.t. and collecting duct to salt |
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Salivary amylase
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secreted in mouth by salivary glands; begins breakdown of starch into maltose
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Peristalsis
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Muscular contractions that move food through esophagus
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Purposes of the stomach
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1 - storage
2 - mixing (into chyme) 3 - physical breakdown (protein denaturing, muscle action) 4 - chemical breakdown (proteins broken by pepsin) 5 - controlled release (chyme movement into sm. intestine controlled by pyloric sphincter |
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Proteolytic enzymes
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AKA proteases
Digest proteins Include trypsin and chymotrypsin Produced by wall of sm. intestine |
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Proteolytic enzymes
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AKA proteases
Digest proteins - aminopeptidase (sm. intestine) - trypsin (pancreas) - chymotrypsin (pancreas) |
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Phosphatases
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enzymes from the small intestine
digest nucleotides |
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Enzymes for starch digestion
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- maltase (sm. intestine)
- lactast (sm. intestine) - pancreatic amylase (pancreas) - salivary amylase (mouth) |
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Gastrin
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- hormone used in digestion
- produced by stomach lining cells when food reaches stomach or body senses food availability; stimulates cells to produce gastric juices |
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Secretin
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- produced by cells of duodenum
- stimulates pancreas to produce bicarbonate to neutralize acid chyme |
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Cholecystokinin
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- produced by small intestine
- stimulates gall bladder to release bile |
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Auxin
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AKA indoleacetic acid (IAA)
- promotes elongation of cells - increases H+ in primary cell walls, loosening cellulose fibers, which lets turgor pressure make cell expand |
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Gibberellins
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AKA giberellic acid (more than 60 types)
- interact with auxins to stimulate shoot growth - promote fruit development - promote seed germiniation - inhibit aging of leaves |
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Cytokinins
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- stimulate cytokinesis
- influence direction of organogenesis - stimulate growth of lateral buds - delay senescence |
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Ethylene
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- gas that promotes ripening of fruit
- stimulates flower production - inhibits elongation of roots, stems, and leaves - influences leaf abscission |
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Abscissic acid (ABA)
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- growth inhibitor
- in buds, causes scales to form for dormancy periods - dormancy broken by giberellins |
