This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: RESPIRATORY SYSTEM Gas exchange = uptake of O 2 and discharge of CO 2 Respiratory medium = source of O 2 (air for terrestrial animals, water for aquatic animals) Water- keeps respiratory cells moist, but O 2 concentration is low Air- High O 2 concentration and easier to pump than water, but difficult to keep cells moist Respiratory surface A. gases must DIFFUSE across membrane, so resp. surfaces are usually thin with large surface area to maximize gas exchange B. Cells must remain moist to maintain plasma membrane, so respiratory surfaces are moist. O 2 and CO 2 diffuse across these surfaces after dissolving in water. SIMPLE ANIMALS (sponges, cnidarians, flatworms) Gases diffuse across plasma membrane of every cell in the body MORE COMPLEX ANIMALS Bulk of body doesnt have access to respiratory medium Earthworms, amphibians - Respiration across entire outer skin...
View Full Document
- Fall '11