controlling the internal environment thermoregulationosmoregulationexcretion
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Controlling the Internal Controlling the Internal EnvironmentEnvironment
ThermoregulationThermoregulation
OsmoregulationOsmoregulation
ExcretionExcretion
Heat ExchangeHeat Exchange
• Conduction - direct transfer of heat
• Convection - transfer of heat by the movement of air or water across a surface
• Radiation - emission of electromagnetic waves
• Evaporation - loss of heat from changing a liquid into a gas
Thermoregulation AdjustmentsThermoregulation Adjustments
• Adjusting the rate of heat exchange– vasodilation/vasoconstiction– countercurrent heat exchange
• Cooling by evaporation
• Behavioral responses
• Changing the rate of metabolic heat production
Endothermic Endothermic AnimalsAnimals
• Fish– Bluefin tuna– Swordfish– Great white shark
• Countercurrent heat exchange
Amphibians and ReptilesAmphibians and Reptiles
• Most are ectothermic– regulate temperature by behavior
Mammals and Mammals and BirdsBirds
• Contraction of muscles– moving– shivering
• Nonshivering thermogenesis– triggered by
hormones
Feedback MechanismsFeedback Mechanisms
• High body temperature– hypothalamus
activates skin blood vessels to dilate and the sweat glands to produce sweat
• Low body temperature– hypothalamus
activates skin blood vessels to constrict and the skeletal muscles to shiver
Temperature Range Temperature Range AdjustmentsAdjustments
• Slow changes– acclimatization (enzymes and membranes)
• Fast changes– heat-shock proteins
OsmoregulationOsmoregulation
• Marine Fish– hypoosmotic– lose water to environment– must excrete salt– small amounts of urine
• Freshwater Fish– hyperosmotic– gain water from
environment– must take in salt– large amounts of urine
Functions of the Functions of the Excretory SystemExcretory System
• Filtration• Reabsorption• Secretion• Excretion
Invertebrate StructuresInvertebrate Structures
• Protonephridia (flame cells)
• network of closed tubules
• used mostly for osmoregulation
• found in platyhelminthes, some annelids, mollusk larvae
Invertebrate StructuresInvertebrate Structures• Open tubules surrounded by a nephrostome• Osmoregulation and excretion• Found in annelids
Invertebrate StructuresInvertebrate Structures• Malpighian
Tubules• Open into the
digestive tract• Osmoregulation
and excretion• Insects and
terrestrial arthropods
Excretory SystemsExcretory SystemsOrigins in VertebratesOrigins in Vertebrates
• Pronephros, Mesonephros, Metanephros
Vertebrate Excretory SystemsVertebrate Excretory Systems
• Pronephros– adult hagfish, embryonic fish, amphibians,
reptiles, birds, mammals
• Mesonephros– adult lamprey, fish, amphibians, embryonic
reptiles, birds, mammals
• Metanephros– adult reptiles, birds, mammals
Blood Filtrate to UrineBlood Filtrate to Urine
• Bowman’s Capsule and the Glomerulus– (filters the blood)
• Proximal tubule– reabsorbed (NaCl, Potassium, Water,
Nutrients)– secretes ( ammonia)– regulates (pH)
Blood Filtrate to UrineBlood Filtrate to Urine
• Loop of Henle – Descending loop
• reabsorbed (water)
– Ascending loop• reabsorbed (NaCl)
Blood Filtrate to UrineBlood Filtrate to Urine
• Distal tubule– reabsorbed (NaCl, Water)– secrete (potassium)– regulate (pH)
• Collecting duct– reabsorbed (NaCl, Water, Urea)