Chapter 49 - Chapter 49 Gas Exchange What physical Factors...

Info icon This preview shows pages 1–3. Sign up to view the full content.

Chapter 49: Gas Exchange What physical Factors Govern Respiratory Gas Exchange? Cells obtain O2 from environment to produce ATP, and CO2 is end product of cellular respiration, and must be removed from the body to prevent toxic effects Diffusion of gases is driven by partial pressure differences o A gas diffuses from a phase with higher partial pressure to lower partial pressure o Solubility is higher at low temperatures o For water breathing animals, the warmer the water is, the less O2 there is per liter of water Fick’s Law applies to all systems of gas exchange o Law: Q= DA (P1-P2)/L Q is rate at which the gas diffuses, D = diffusion coefficient, A= area of diffusion, P1 and P2 are partial pressure differences, L is path length Air is a better respiratory medium than water o Even air breathing animals suffer from slow rate of diffusion of O2 in water o Animals that lack internal systems for distributing O2 are small, flat bodies with large external surface area that are highly permeable to respiratory gases o O2 can be obtained more easily from air than water because: O2 concentrations are higher in air, O2 has higher diffusion constant, and more energy is required to move O2 in water than air High temperatures Create respiratory problems for aquatic animals o Most are ectotherms, so as water rises, body temp and metabolic rate rises, so they need more O2 to survive. However, warmer water holds less O2 O2 availability decreases with altitude CO2 is lost by diffusion o CO2 in atmosphere is very low, so large concentration gradient to get CO2 out of the body What Adaptations maximize respiratory gas exchange? Increased surface area (A): respiratory organs have large SA o External/ internal gills are highly branched and folded, they minimize path length o Lungs- have large SAs because division and elasticity (inflation and deflation) o Tracheae- network of air-filled tubes that branch, large SA
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern