8 6 mechanisms for gas exchange 1. Diffusion through cell membraneEx: Single Cell2. Diffusion through skinEx: Earthworm3. Papillae- Increased folds in skinEx: Echinoderms4. Spiracles and tracheaeEx: Insects5. GillsEx: Fish6. Alveoli of LungsEx: Mammals
10 Figure 42.22 Gills are Shown In Pink CoelomGillsGillsFigure Diversity in the structure of gills, external body surfaces that function in gas exchange.Tube footParapodium(functions as gill)(a) Marine worm(b) Crayfish(c) Sea star
12 Countercurrent exchange PO (mm Hg) in water 2 Figure 42.23O2-poor bloodGillarchO2-rich bloodLamellaBloodvesselsGill archWaterflowOperculumWater flowBlood flowCountercurrent exchangeFigure The structure and function of fish gills.PO (mm Hg) in water2150120906030Gill filamentsNet diffu-sion of O2140110805020PO (mm Hg)in blood2
14 Tracheoles Mitochondria Muscle fiber 2.5 m Body cell Tracheae Air sac Figure 42.24TracheolesMitochondriaMuscle fiber2.5 mBodycellTracheaeAirsacTracheoleFigure Tracheal systems.Air sacsTracheaAirExternal opening
15 Amphibians and Reptiles Amphibians have lungs but also supplement their respiration through moist skin- cutaneous respiration.Reptiles have a partially divided ventricle that more efficiently separates oxygenated from deoxygenated blood, reducing the need for cutaneous respiration. Turtles supplement their respiration through skin on their ____!
16 What structures are involved in mammal gas exchange?
21 Let’s model how the blood gets oxygen to every body cell. Oxygen in the blood is affixed to _______The more that the tissue needs oxygen, the lower the affinity of hemoglobin for oxygen.
22 Modeling O2 Delivery 8 students are hemoglobin- cups with 4 O Each table is a body cell- 1 cup with 4 OBody cells are digestive, brain, skeletal muscleEvery hemoglobin has a route, one row.Body Cells use O2Warm up- Every cell uses 1/ 20 secRaise hand when need an oxygenActive tissue uses 1/10 sec, vary which tissue is active
23 Figure 42.31 Oxyhemoglobin dissociation curve 100100O2 unloadedto tissuesat restpH 7.48080pH 7.2O2 unloadedto tissuesduring exerciseHemoglobinretains lessO2 at lower pH(higher CO2concentration)6060O2 saturation of hemoglobin (%)O2 saturation of hemoglobin (%)404020202040608010020406080100Figure Dissociation curves for hemoglobin at 37°C.PO (mm Hg)Tissues duringexerciseTissuesat restLungs2(b) pH and hemoglobin dissociationPO (mm Hg)22(a) PO and hemoglobin dissociation at pH 7.4
24 O2 saturation of hemoglobin (%) Figure 42.31b100pH 7.480pH 7.2Hemoglobinretains lessO2 at lower pH(higher CO2concentration)60O2 saturation of hemoglobin (%)4020Figure Dissociation curves for hemoglobin at 37°C.20406080100PO (mm Hg)2(b) pH and hemoglobin dissociation
25 Oxyhemoglobin dissociation curve What effect does exercise have on the curve?How do you think a fetus’ curve would look(shift left or shift right?).