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27.3 Circulation. Open circulatory system - blood vessels empty into sinuses or spongy cavities (insects). Closed circulatory systems - blood stays entirely in vessels. Reptiles lose ability to breathe through skin and begin to partition heart into four chambers.
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Open circulatory system - blood vessels empty into sinuses or spongy cavities (insects)
Closed circulatory systems - blood stays entirely in vessels
Reptiles lose ability to breathe through skin and begin to partition heart into four chambers.
Atrium - receives blood from body • Ventricle - pumps blood out of heart
human heart surgery • heart beating animation
Excretion - elimination of metabolic wastes, such as nitrogenous compounds • Ammonia (NH3) - toxic substance that cannot be stored for long, produced by protein metabolism
Animals in wet environments can allow ammonia to diffuse though skin (fish) Other animals convert ammonia to harmless compounds: (uric acid for insects, reptiles and birds) (urea (water soluble) for mammals and some amphibians)
Why is bird feces white? Birds don’t urinate, so the nitrogenous waste (uric acid) is mixed in with the solid feces. Uric acid makes the feces white colored.
Uric acid = not water soluble, can lead to kidney stones in humans
Kidneys- separate waste and excess water from blood, keep water balance - used by terrestrial vertebrates
Aquatic animal excretion problems - diffusion 1) Freshwater vertebrates - water diffuses into body, salt diffuses out flame cells - push excess water out of body (flatworms) Urine is also filled with water (dilute)
Saltwater vertebrates a) lose water to their salty surroundings b) Actively excrete salt out of gills c) Produce very concentrated urine to save water