1 Comparative physiology Lecture -3- Oxygen (Respiration ) By : Saib Al owini P(16-25)

2 Four basic respiratory systems 1. Diffusion across integument 2. Gills: evagenation ( turned out) May be found in sac 3. Lungs invagenation ( turned in) Pulmonate land snail -1 st - Term lung used if meida is air or water 4. Tracheae -Spiracles and trachea -Blood dosnt transport system

3 Respiratory in water Small animals diffusion Large animals respiratory organs Animal without specialized resp organ. - small sphere : with small respiratory surface -enlargement by deviation on sphere: large surface - O 2 Concentration on surface which sufficient to animal for metabolic ( by diffusion )is

4 FO 2 = VO 2 * R 2 / 6K F O2= con surface O2 ( as fraction of atm pressure) VO2 = rateO2 consumption cm3/cm3R2 = radiusK =diffusion constantK= cm3 of oxygen that will diffuse /min in area 1cm3 and1atm

5 Example Animal has FO2= ? VO2 =0.001 ml /g R2 = 1 cm K =11*10 -6 O2 pressure required = 15 atm (not found) If animal 1mm atm O2 found Aerated Water have 0.21 atm o 2

6 Animals which use diffusion 1- small as protozoa 2- very low metabolic rate as Jellyfish has -Flattened body -1% organic the other are water salts So - has low metabolic -Wide but thin body wide respiratory surface -Active cell on surface no distance diffusion

7 If the animal is larger it will have Flattened body Or increase respiratory surface Ex, Sponges, corals

8 Animal with respiratory organs Diffusion is not suffice. Then we found respiratory organs with -Large surface -Thinner membrane

9 Four basic respiratory systems 1. Diffusion across integument 2. Gills: evagenation ( turned out) May be found in sac 3. Lungs invagenation ( turned in) Pulmonate land snail -1 st - Term lung used if meida is air or water 4. Tracheae -Spiracles and trachea -Blood dosnt transport system Animals with respiratory organs

10 Effective respiratory organs : -Large surface -- thin membrane -* Gills usually in water -* lungs usually in air -

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15 Some lunges live in water Sea cucumber use lung in water -* Some gills may modified to act in air but most fish have been Asphyxiated in air. Water support gills, air cannot so gills tend to stick together by surface adhesion. Resulted in decreasing respiratory surface

16 Sea Cucumbers are the only marine invertebrate with a true tidal lung that suctions water in and then pushes it back out the same aperature (Anus)

17 Ventilation of gills Water must renewal by various mechanisms 1- moving gill through water -Small organism, some aquatic insects (may flay larvae). -Large Energy required to resist water -Ex, large aquatic salamander mudpuppy

18 Gill ventillation

19 Ventilation of gills 2- moving water over respiratory surface: More feasible A- by ciliary's action Mussel, clams -Spongy move water by flagella. B- moving water by mechanical pump like devise

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21 Primitive mollusk

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23 B- moving water by mechanical pump like devise Fish and crabs Low coast 3 - movement of animals ( immobile gill cover) Cannt survive without swimming Sequid,octopus take water into mantel cavity then eject it through siphon

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25 Gas exchange and water flow For active gas exchange : - Highly active fish have the largest relative gill area ex(: fast mackerel has gill surface equal 50 times of bottom living goose fish ) -High rate of water flow - gill cavity provide protection, permit water to perfuse over gills.

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27 Counter current Several major gill arches on each side From each arise two rows of gill filaments Tips of filament arch meet Each filament caries densely packed flat lamella in rows

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29 -Water flow between lamella opposite to blood flow -What is the aim!! -What is the difference if they flow together or cross other !!!

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31 Scheid and Piiper (1997) eff. aff. filament water counter-current flow is key to oxygen extraction efficiency in aquatic respiration gill arch secondary lamella filament efferent & afferent arteries secondary lamella

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33 Oxygen transfer from the environmental medium to the blood (Part 1) No respiratory system is designed this way

34 by cross-current exchange

35 Oxygen transfer from the environmental medium to the blood (Part 2)

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37 Oxygen uptake to blood still even highest level of o 2 reach Water will meet blood with lower o 2 even the end Water leave with lost of % but mammals remove ¼ air initial o 2

38 Oxygen transfer from the environmental medium to the blood in a tidally ventilated lung

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40 Concurrent : Little o2 uptake More energy consuming Crabs : have low efficiency counter current Because blood diffusion briar is grater European shore crab 7-30 extraction In other crabs 50%

41 What is water resistance levels through the gills? Hughes (1966) calculated that flow through gills of a 150 g tench (Tinca) for a pressure of 5 mm water ~ 10.1 ml/s Normal volume of water passed through fish gills = 1-2 ml/s.( 0.02 mm between lamella) Conclusion: Gill lamellae do not offer much resistance to flow

42 How do fish pump water over their gills? Double set of pumps (oral cavity and opercular cavity) Volume of oral cavity can be changed by lowering jaw (pump 1) Volume of second pump changed by increased movements of opercular flap (pump 2)

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44 The pressure in the two cavities are linked Pressure drops when mouth begins to open; increases as mouth is closed

45 Opercular pumping in fish Gill chamber is rigid (opercular cavity) Can be sealed by a flap (operculum) Bottom of the opercular chamber is muscular and can be raised or lowered Pump cycle: –Mouth open, operculum closed Bottom of chamber drops, chamber fills –Mouth closed Bottom of chamber is raised, squeezing water out through operculum

46 Buccal-opercular pump during inhalation (Eckert, Fig ) 13

47 Buccal-opercular pump during exhalation 14

48 Ventilation Buccal-opercular pumping

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51 Ram ventilation Some fish use water pumping; they survive by swimming to pass water through gills = ram ventilation Some fish species only use ram ventilation (e.g., tunas) Other species use water pumping at low speeds, switch to ram ventilation at high speeds Fish adjust openings of their mouths to modulate water flow

52 Example: Mackerel swimming in water with less oxygen opened their mouths more The lowered oxygen supply was compensated by increased water flow

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54 Ram ventilation is more economic on high speed If low oxygen mouth opining increase

55 Coughing Solid particles in water tend to caught in gills Closed lips with enlargement of buccal cavity lowering pressure As coughing in animal Crabs revers each 1-10/min To maintain gills clear.

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