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Respiratory System. Size, shape and diffusion. All body cells need to obtain Oxygen molecules and eliminate carbon dioxide Gas exchange These gases move by diffusion, But diffusion slow Implication: Two steps of gas exchange in large animals
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All body cells need to obtain Oxygen molecules and eliminate carbon dioxide Gas exchange These gases move by diffusion, But diffusion slow Implication: Two steps of gas exchange in large animals Oxygen must be dissolved in water before animals can take it up. Implication: Water bodies have less dissolved oxygen than the atmosphere Implication: Water also is more dense than air Implication: Why do we need oxygen?
An advantage of gas exchange in fresh water, compared with gas exchange in air, is that _____. ventilation requires less energy in water the respiratory surface does not have to be as extensive in water water is easier to move over the respiratory surface water loss through evaporation across the respiratory surface can be minimized water usually contains a higher concentration of oxygen than air
Moist skin as the only respiratory organ Animals with no respiratory system or circulatory system: Sponges and Cnidarians Flatworms Animals with no respiratory system but circulatory: Earthworms All of these are restricted in which way?
The diversity of respiratory organs THE DIVERSITY OF RESPIRATORY ORGANS Gills (extensions of the body surface) Tracheae (branching internal tubes) Lungs (localized internal organs) Skin (entire body surface) Tracheae (internal tubes) Gills Lungs (internal sacs) Stinkbug Opossum Sea slug Leech O2 CO2 CO2 CO2 O2 O2 CO2 O2 O2 CO2 Respiratory surface (skin) No capillaries Respiratory surface (gills) Respiratory surface (lungs) Respiratory surface (tracheae) Capillary Capillary Capillary
Which of the following organisms has no specialized respiratory structures? alligators ants salmon earthworms crabs
Gills are outfoldings of the body surrounded by water Mollusks pump water into mantel cavity Some crustaceans have gills on their legs Sea stars: scattered projections Marine worms (annelida): parapodia (also for walking)
Gills are outfoldings of the body surrounded by water Amphibians move their external gills Fish: gills behind the body wall
Fish gills remove 80% of the oxygen from water by a countercurrent exchange Flow of blood is in the opposite direction than the flow of water, Fish extract more oxygen than if blood moved in the same direction Why can’t gills work on land?
Which statement about the gas exchange system in fish is correct? It enables oxygen to move from where its partial pressure is lower to where its partial pressure is higher. It enables oxygen to diffuse from the water into the blood over the entire length of the gill capillaries. It relies on the parallel flow of blood and water in the gills. What would be the consequence if we were to reverse the direction of water flow over the gills of a fish, moving water inward past the operculum, past the gills, then out the mouth? This reversal of water flow would ________. reduce efficiency of gas exchange change the exchange of gases in the body from carbon dioxide out and oxygen in to carbon dioxide in and oxygen out increase the efficiency of gas exchange
Internal respiratory surfaces for land animals Land slugs and snails: mantle cavity works as a lung Insects, centipedes and some spiders: Tracheae system of tubes that bring oxygen directly to tissues Spiracles are openings on the side of the body
Internal respiratory surfaces for land animals Vertebrates: lungs Lung fish
Lungs in Mammals Which of the following represents the correct flow of air into the lung of a mammal? larnyx → trachea → bronchi → bronchioles → alveoli trachea → bronchioles → bronchi → alveoli alveoli → tracheoles → bronchi → trachea trachea → tracheoles → bronchi → alveoli True or false? The lungs of humans form from the embryonic foregut. True False
Lungs in Mammals Which of the following represents the correct flow of air into the lung of a mammal? larnyx → trachea → bronchi → bronchioles → alveoli trachea → bronchioles → bronchi → alveoli alveoli → tracheoles → bronchi → trachea trachea → tracheoles → bronchi → alveoli Which lung structure is is in charge of gas exchange? Traquea Borchi Bronquiole Alveoli True or false? The lungs of humans form from the embryonic foregut. True False
Which barrier(s) must O2 and CO2 cross to pass between air and blood inside lungs? Check all that apply. diaphragm epithelial cells extracellular fluid capillary wall After blood becomes oxygenated, it returns to the heart, and is then pumped to the lungs. it returns to the heart, and is then pumped to body cells. it does not return to the heart, but goes to the nose and mouth. it does not return to the heart, but goes directly to capillaries that supply the body's cells with oxygen. it does not return to the heart, but goes directly to the lungs.
Amphibian lungs is a simple sac, most O2 is obtain across ____________ Reptiles: skin is _________, lungs posses alveoli
Which statement is correct? Oxygen diffuses from large blood vessels into the body's cells. In the blood, oxygen is bound to hemoglobin, a protein found in red blood cells. Oxygen is released from the mitochondria as a product of cellular respiration. Carbon dioxide diffuses from the alveoli into surrounding capillaries. As oxygen diffuses from the lungs into capillaries, blood becomes deoxygenated.
