Nutrition in animals Types of digestivesystems
Whatisdigestion? • Digestionisthemechanical and chemicalbreakdown of foodintosmallercomponentsthat are more easilyabsorbedinto a bloodstream, forinstance. Digestionis a form of catabolism: a breakdown of largefoodmoleculestosmallerones.
Types of digestion in animals: • . Externaldigestionis more primitive, and mostfungistillrelyonit. In thisprocess, enzymes are secretedintotheenvironmentsurroundingtheorganism, wherethey break downanorganic material, and some of theproductsdiffuse back totheorganismgastrovascular cavity:Extracellulardigestiontakes place withinthiscavity. It has onlyoneopeningtotheoutsidethat functions as both a mouth and ananus.
Internaldigestion • Animalsform a tube in whichinternaldigestionoccurs, whichis more efficientbecause more of thebrokendownproducts can becaptured, and theinternalchemicalenvironment can be more efficientlycontrolled.
Stages in the Digestive Process • Breakingtheselargemoleculesintosmallercomponentsinvolves: • Ingestion: theintake of food • movement: propels food through the digestive system • secretion: release of digestive juices in response to a specific stimulus • digestion: breakdown of food into molecular components small enough to cross the plasma membrane • absorption: passage of the molecules into the body's interior and their passage throughout the body • elimination: removal of undigested food and wastes
Cutaneusrespiration: gas exchangeiscarriedoutthroughtheskin. • The Body Surface: moist skin • Flatworms and annelids use their outer surfaces as gas exchange surfaces. Earthworms have a series of thin-walled blood vessels known as capillaries. Gas exchange occurs at capillaries located throughout the body as well as those in the respiratory surface. • Adult Amphibians use their skin as a respiratory surface.
Respiration in animals: a waytointakeoxygen- Branchialrespiration
Gills and tracheae: trachealrespiration.tracheaeend in orificescalledspiracles
Pulmonaryrespiration: Lungs • Internalcavitieswhichhaveverythin, dampwalls full of bloodvessels. • Movements: inhalation and exhalation • (Inhalar y exalar) • Vertebrates and someinvertebratesliketerrestrialsnails. • http://www.youtube.com/watch?feature=player_embedded&v=obnAWTWdV7c • http://www.youtube.com/watch?v=rNTEOCFmOIQ
Circulatorysystem: itcarriesoxygen and nutrientstothecells and removescarbondioxide and wastes • Types: • Open circulatorysystem: theheartpumpsthe fluid throughthebodycavitydirectlytotheorgans. (Molluscs and arthropods) • Closedcirculatorysystem: Thebloodalwayscirculatesinsidebloodvesselspumpedby a heart. Simple (fish) and double (mammals) • Simple: thebloodpasses once throughtheheartand thegills. • Double: thebloodpassesthroughthehearttwice. Firstloop: heart-lungs-heart • Secondloop: heart-body-heart
Excretion: theprocess of collectingwasteproducts and expellingthemoutside. • Carbondioxide: respiratorysystem • Ammoniac and urea: excretorysystem • Someanimalsexpelwastesdirectlythroughthe pores(sponges) • Insects: Malpighiantubules • Vertebrates: Kidneys, ureteres, bladder and urethra.