Chapter 5: Buoyancy and Thermal Reading Assignment: Chapter 5: Buoyancy and Thermal Regulation bigeye jack end

Hemoglobin--molecule of O2 transport Structure protein monomer in Myxini & Cephalasipdomorphi tetramer in Gnathostomata (4 polypeptide chains)  chain similar in coelacanth and tadpole end

Hemoglobin (Hg) cont. Occurrence: erythrocytes (RBCs) up to 4M RBC/mm3 of blood RBC’s nucleated in fish Hg Absent in some species (Channichthyidae) Antarctic ice fish fish human end

Some species have more than one type of hemoglobin Catostomus clarki -- desert sucker has an additional form of pH insensitive Hg end

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Factors affecting blood oxygen affinity pH pCO2 (partial pressure of carbon dioxide) end

data for winter flounder Effect of pH on Hg--two components 100 50 pH 8.02 2. capacity Root pH 7.47 1.affinity % Saturation of Hg data for winter flounder Bohr 80 160 pO2 mm Mercury Air saturation end

affinity: strength of attraction of Hg for O2 Bohr effect--decrease in affinity of hemoglobin for O2 due to decreasing pH or increasing PCO2 affinity: strength of attraction of Hg for O2 Root effect--decrease in capacity of Hg for O2 due to decreasing pH or increasing PCO2 (extreme Bohr effect) capacity: total quantity O2 of that Hg can carry end

more active species tend to have greater Bohr & Root effects red versus white muscle myoglobin perciform skipjack tuna lamnid shark end

Advantage of Bohr Effect blood circulation Gills Tissues pCO2? pCO2 higher pCO2 lower lactic acid? lactic acid no lactic acid pH? pH lower pH higher end

Teleost Heart: atrium sinus venosus bulbus arteriosus ventricle end

Teleost Heart: atrium sinus venosus bulbus arteriosus relax ventricle end

Teleost Heart: atrium sinus venosus bulbus arteriosus contract ventricle end

Conus arteriosus--Myxini, Ceph., elasmobranchs, gar to gills heart end

bulbus arteriosus 60 Pressure (mm merc.) ventricle time end

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Buoyancy strategies 1. Low density compounds 2. Lift generated by swimming 3. Reduction of heavy tissues 4. Swim bladder (air bladder) end

1. Low density compounds: Substance Specific Gravity Bone 2.0 Muscle 1.05 Cartilage 1.1 Freshwater 1.002 @20C Saltwater 1.072 @20C Lipids 0.9-0.92 Squalene 0.86 Advantages/disadvantages end

2. Lift generated by swimming: thrust lift lift sharks Advantages/disadvantages end

hammerhead shark end

nurse shark end

sandbar shark end

3. Reduction of heavy tissues Eurypharynx pelecanoides deepwater fishes Advantages/disadvantages end

umbrella mouth gulper end

umbrella mouth gulper end

4. Swim bladder low density adjustable most osteichthians lost secondarily in some species end

Two types of swim bladders: Physostomous pneumatic duct soft-rayed teleosts--herrings, salmonids, catfishes, cyprinids, eels, etc. Physoclistous blood/circulatory system spiney-rayed teleosts--Acanthopterygii, sunfishes, perch, most marine fishes end

Effects of depth on swim bladder volume pressure increases 1 ATM/10m swim bladder must be adjustable Physostomous fishes adjust volume by gulping or spitting air. mostly shallow water species gas-spitting reflex gulp air at surface end

Physoclistous inflation/deflation circulatory system--source of gases rete mirabile (wonderful net) --inflation oval window--deflation Problem: fish need greater pressure in swim bladder than is achieved by equilibrium with blood gases end

Oxygen equilibrium—swim bladder inflation hemoglobin O2 gills swim bladder water plasma O2 swim bladder O2 end

Counter-current multiplication system Diagram of basic functional unit (inflation) lactic acid afferent blood O2heme  pO2 O2heme 1 pO2 pO2 swim bladder O2heme  pO2  efferent blood end

Function of Rete Mirabile 1. Hemoglobin saturated with O2 (O2 heme) plasma O2 low (p O2) end

Counter-current multiplication system lactic acid afferent blood O2heme  pO2 O2heme 1 2 pO2 pO2 swim bladder O2heme  pO2  efferent blood end

Function of Rete Mirabile 2. Lactic Acid Secretions heme dumps O2 to plasma pO2 diffuses into swim bladder to equil. end

Counter-current multiplication system lactic acid afferent blood O2heme  pO2 O2heme 1 2 pO2 pO2 swim bladder O2heme  pO2  3 efferent blood end

Function of Rete Mirabile 3. Multiplying effect: pO2 diffuses from efferent capillary to afferent cap. Longer capillaries yield more efficient exchange of oxygen, higher pressures end

Physoclistous swim bladder Pressures up to 300 ATM in some deep sea fishes Gases mostly O2, some CO2 and N2 Guanine crystals in SB wall reduce permeability Deflation occurs at oval window dense bed of capillaries on SB wall gasses diffuse into blood mucus layer covers window during inflation end

Summary: Diffusion of O2; controlled by structure & function Relationship O2 bound to hemoglobin versus O2 in plasma Effect of pH on affinity/capacity of hemoglobin for O2 Counter-current multiplier length of capillaries counter-current flow of blood end

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mya Era Periods 65 248 ? 590

Ardoch Manvel Inkster Grand Forks Hwy 18 I29 Hwy 1 to Johnstown Hwy 81 Forest River UND Biol. Area farm house stop here tree line 0.5 mi Turn right on gravel road just past tree line, go north for 0.5 mi, turn right on two-track road just before Farm house, pass ravine on left and turn left following Ravine on the left, stop by chain link fence compound. 3 mi Inkster Hwy 18 Grand Forks