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63 Cards in this Set
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Thermoregulation |
- Maintaining the body temperature eithin a range that permits cells to function efficiently |
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Osmoregulation |
- Adaptation to osmotic environment |
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Excretion |
- Strategies for the elimination of waste products or protein catabolism |
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Conduction |
- Direct transfer of heat between molecules of the encmvironment and a body surface - Higher -> lower temp - Water is 50-100 times more effective in condicting heat: why animals in cold water cool more rapidly |
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Convection |
- Transfer of heat by the movement of air or liquid past a body surface (e.g. breeze) |
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Radiation |
- Emission of electromagnetic waves produced by all objects warmer than absolute zero - Does not require direct contact (e.g. sunlight) - Only heat transfer process able to minimally affect aquatic animals |
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Evaporation |
- Loss of heat from a liquid's surface as some molecules are lost as gas - Panting, sweat, bathing -> evaporative cooling, if surrounding air is not humid - Some birds: vascularized pouches in floor of mouth flutter -> increases evap cooming - Most amphibians: lose heat through evap cooling - Reptiles: regulate temp behaviorally by orienting selves - Mammals: may spread saliva (kang, rodents), saliva + urine (bats) to increase evap heat loss - Along with convection, most variable cause of heat loss |
In different animal types |
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Ectotherm |
- Derives body heat from surroundings + small amount from metabolism - E.g. most invertebrates, fishes, reptiles, and amphibians - Most ectothermic insects and fish are partial endotherms -> use metabolic heat to warm only certain body parts (e.g. locomotor muscles) |
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Endotherm |
- Derives most or all body heat from metabolism - E.g. mammals, birds, fishes, insects - Active metabolism -> high level of cellular respiration -> can be physically active for longer, consume more food - Enhances activity level of fishes by keeping swimming muscles warm - Evolution of endothermy -> withstand environmental fluctuations in terrestrial habitats |
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Vasodilation |
- Method of regulating heat exchange between animal and surroundings - Nerve signals -> BV wall muscles relax -> more blood flow -> activates sweat glands -> more heat transfer w/ surroundings |
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Vasoconstriction |
- Reduces blood flow -> warm blood diverted from skin to deeper tissues -> reduces heat transferred to environment -> activates skeletal muscles -> shivering, nonshivering thermogenesis - Occurs in cold |
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Countercurrent heat exchanger |
- Special arrangement of arteries and veins found in extremities of some endothermic animals - Arteries carrying warm blood come into contact with veins -> warm venous blood - Rate controlled by amount of venous blood that enters appendage - Maintains high temperature in thorax where flight muscles are located in bees, noctuid moths - Reduce heat loss in extremities with no blubber |
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Nonshivering thermogenesis |
- Along with skeletal muscle activity, increases amount of metabolic heat produced - Only birds and mammals - Hormonal triggering of heat production |
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Brown fat |
- Fat in shoulders and neck specialized for rapid heat production - Layer of fat below skin provides insulation: very thick in marine mammals, blubber - Found in mammals |
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Acclimatization |
- Physiological response that allows many animals to adjust to a new range of envi temp - Days/weeks, important for seasonal change - May involve cellular-level adjustments: increase prod. of certain enzymes to compensate foe lower activity of molecules; produce enzyme variants that have same fxn but diff. temp optima |
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Stress-induced proteins |
- Production stimulated in large temperature increase |
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Heat-shock proteins |
- Found in animal cells, yeast, bacteria - Help prevent protein denaturation and cell death - Homeostasis while organism adjusts to external environment |
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Torpor |
- Occurs when food supply is low and/or envi temps are extreme - Metabolism decreases, heat and respiratory systems slow down - Short-term: allow small endotherms with high metabolic rate/rate of energy consumption to survive on stored energy when they cannot feed - Bats and shrews enter torpor in day, chickadees and hummingbirds in cold nights - Some enter daily: human sleep, shrews |
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Hibernation |
- Type of torpor where body temp is lowered - Animal can survive cold and diminished food supply (some eat more as daylight decreases) |
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Estivation |
- Type of torpor characterized by slow metabolism and inactivity - Animal can survive heat and diminished water supply |
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Transport epithelium |
- Manage water balance, ion balance, and excretion of metabolic wastes - Regulate movement of solutes between internal fluids and external envi - (1) Single layer of cells joined by tight junctions, arranged in tubular networks with extensive SA (2) Channel (3) opening (4) external envi - Composition determines fxn; Birds: eliminate excess salts; Gills: pumps salt in/out based on if marine or freshwater |
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Ammonia |
- Toxic waste product of protein and nucleic acid metabolism - Water-soluble, permeates membranes - Invertebrates: diffuses across body surface - Fishes: Gill epithelium take up Na+ in water, expel NH4+ -> high Na+ in blod |
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Urea and Uric acid |
- Urea: mammals, adult amphibians (initially ammonia) - (1) NH4+ + CO2 in liver -> (2) kidneys via circulatory - Trimethylamine oxide (TMAO): protects shark proteins from denaturatiin by urea - Uric acid: land snails, insects, birds, reptiles - UA less soluble, excreted as pastelike precipitate through cloaca - If embryo releases ammonia/urea, can be stored as solid within egg - Terrestrial reptiles: mostly UA, crocodiles: ammonia and UA, aquatic turtles: urea, ammonia |
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Osmolarity |
- Total solute concentration - Hyperosmotic: greater solute concentration - Freshwaternanimals hyperosmotic to environment, so take in water |
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Osmoconformer |
- Animals do not actively adjust internal osmolarity - Body fluids isotonic with surroundings - Marine invertebrates |
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Osmoregulator |
- Animals regulate external osmolarity by discharging/taking in excess water - Marine animals, freshwater/terrestrial animals - Adaptations: protective outer layers, waxy cuticles, being nocturnal |
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Stenohaline |
- Animal that cannot survive a wide fluctuation in external osmolarity |
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Euryhaline |
- Animal can survive wide fluctuation in external osmolarity - E.g. anandromous fishes like salmon, which migrate between seawater and freshwater |
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Anhydrobiosis |
- Permits aquatic invertebrates to survive in dormant state when their habitat dries up e.g. tardigeades - Dehydrated and frozen animals contain disaccharide trehalose -> appears to replace water |
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Filtration |
- First step of urine production - Second step: modification of filtrate |
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Secretion |
- Modification of filtrate: solutes (e.g. salt, toxin) secreted from body fluids into filtrate |
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Reabsorption |
- Solutes reabsorbed from filtrate back into body fluid (e.g. glucose) |
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Protonephridium |
- Flame-bulb excretory system (flatworms, rotifers, some annelids) - Network of closed tubules lacking internal openings, smallest braches capped by flame bulb - (1) interstitial fluid passes through flame bulb (2) propelled by cilia along tubules - Nephridopores: openings through which urine emlties into external environment |
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Metanephridium |
- excretory tubules that have internal openings to collect body fluid, enveloped by network of capillaries that reabsorb essential salts pumped out by transport epithelium - (1) coelomic fluid enters funnel-shaped nephrostome, surrounded by cilia (2) passes through metanephridium (3) empties into a storage baldder that empties outside body - nephrostome collects coelomic fluid from body segment - most annelids |
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Malphigian tubules |
- remove nitrogenous wastes from hemolymph, function in osmoregulation - ouypocketings of gut that open into digestive tract at midgut/hind gut - transport epithelium moves solutes into lumen - from hindgut, fluid moves into rectum -> salt and water reabsorbed, nitrogenous wastes secrted - insects, other terrestrial arthopods |
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Renal artery |
- Where blood enters kidney |
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Renal vein |
- Where blood exits kidney |
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Ureter |
- where urine exits each kidney - two, both drain into urinary bladder - sphincter muscles near junction |
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Urinary bladder |
- stores urine - sphincter muscles near bladder-urethra junction control urination |
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Urethra |
- Where urine leaves body from urinary bladder |
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Renal cortex |
- outer region of kidney - contains nephrons and collecting ducts - each excretory tubule -> network of capillaries |
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Renal medulla |
- inner region of kidney - contains microsocopic nephrons and collecting ducts - hyperosmotic |
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Nephron |
- functional unit of kidney - single long tubule and associated capillaries - in freshwater fish (hyperosmotic to surroundings), nephrons use cilia to exple dilute urine; in amphibians, across skin |
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Glomerulus |
- ball of capillaries - lacking along with capsules in bony marine fishes -> kidneys just rid body of divalent ions taken in through seawater; monovalent ions excrete nitrogenous waste through gills |
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Bowman's capsule |
- cup-shaped blind end of renal tubule that receives filtrate from blood - embraces glomerulus - in cortex with proximal and distal convoluted tubules - if reabsorbed, (2) Bowman's capsule (3) efferent arteriole (4) peritubular capillaries |
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Podocytes |
- specialized cells of capsule - (1) afferent arteriole -> glomerulus (2) lumen of Bowman's capsule - With porous capillaries, nonselectively filter out blood cells and large molecules - filtrate: glucose, salts, vitamins, nitrogenous wastes, small molecules |
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Proximal tubule |
- (3) proximal tubule - secretes H+ ions and reabsorption of bicarb for constant body pH - reabsorbs glucose and amino acids through active transport, returns to interstitial fluid - reabsorbs NaCl and water -> salt diffuses into transport epithelium, membranes pump it out, balanced by passive transport of Cl- and water -> cells facing interstitial fluid have small SA to minimize leakage |
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Loop of Henle |
- (4) loop of Henle (D->A) - long hairpin turn with descending and ascending limb - in descending limb, transport epithelium is freely permeable to water only -> filtrate moving down continues to lose water, NaCl concentration increases - ascending limb permeable to salt but not water -> in thin segment near loop tip, NaCl diffuses out, increasing osmolarity of interstitial fluids; in thick segment near distal tubule, salt actively transported out - longer in dry environments -> concentrated urine |
description, adaptations |
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Distal tubule |
- (5) distal tubule - empties into collecting duct - regulates K+ and H+ secretion, and NaCl and bicarb reapsorption - hypoosmotic to interstitial fluids of cortex |
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Collecting duct |
- Receives filtrate from many nephrons - Filtrate now called presumptive urine - (6) collecting duct (7) renal pelvis (8) ureter - transport epithelium permeable to water but not salt -> filtrate loses water -> urea concentrated in urine - by excreting hyperosmotic urine, kidney can conserve water |
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Cortical nephrons |
- Nephrons with reduced loops of Henle confined to renal cortex - 80% of nephrons in humans - present in mammals and birds, nephrons in other vertebrates lack loop of Henle - reptiles have only cortical nephrons -> isoosmotic urine |
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Juxtamedullary nephrons |
- Nephrons with long looops that extend into renal meduilla - enables mammals to excrete nitrogenous waste without squandering water |
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Afferent arteriole |
- Branch of renal artery that divides to form capillaries of glomerulus |
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Efferent arteriole |
- Forms converging capillaries as they leave the glomerulus |
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Peritubular capillaries |
- Subdivision of efferent arteriole that intermingles with proximal and distal tuibles |
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Vasa recta |
- Capillary system branching downward from peritubular capillaries that serves loop of Henle - Countercurrent system: water lost, NaCl diffused in in descending vessel conveying blood to inner medullal; reversed in ascending vessel that flows towards cortex - Can supply tissues with substances without interfering with osmolarity gradient |
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Antidiuretic hormone |
- enhances fluid retention by increasing water permeability to epithelium to distal tubules and collecting duct - produced by hypothalamus, sotred and released from posterior pituitary - release triggered when osmoreceptor cells decreased increased blood osmolarity - can be inhibited by alcohol -> dehydration |
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Juxtaglomerular apparatus |
- specialized tissue near afferent arterioles which carries blood to glomeruli - responds to decrease in BP or BV, or decrease in Na+ conc in blood |
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Angiotensin II |
- directly increases BP by causing arteriole constriction - indirectly signals alodestorene release, stimulates thirst centers -> drinking, increasing BP and BV |
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Aldosterone |
- Stimulates Na+ reabsorption by distal tubules - Water follows by opsmosis |
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Renin |
- released by JGA inresponse to factors - leads to conversion of inactive angiotensinogen -> active angiotensin II |
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Renin-angiotensin-aldosterone system |
- Feedback circuit that responds to a decrease in BV caused by fluid loss - Ensures balance when ADH increases water reabsorption |
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Atrial natriuretic factor |
- Released by heart's arterial walls in response to increased BV and BP - Inhibits renin release, NaCl absorption, and reduces aldosterone release -> decreases Bv AND LOWERS Bp |
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