Lecture Exam Monday 100 point exam covers lectures, assigned readings 8-12 short answer questions; 4-6 pts ea –complete, concise answer –ex: definition; short description 3-5 longer questions; pts ea Finish by 2:55--budget time Power Point lectures on blackboard Chapters: 1, 2, 12, 13, 3, 14, 4, 15, 5 end

Advantage of Bohr Effect Tissues Gills blood circulation pH lower pH higher pCO 2 higher pCO 2 lower lactic acid no lactic acid end pH? pCO 2 ? lactic acid?

Teleost Heart: sinus venosusatrium ventricle bulbus arteriosus end

Teleost Heart: sinus venosusatrium ventricle bulbus arteriosus end relax

Teleost Heart: sinus venosusatrium ventricle bulbus arteriosus end contract

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

time Pressure (mm merc.) 0 60 ventricle bulbus arteriosus end Effect of bulbus arteriosus on blood pressure

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: Advantages/disadvantages SubstanceSpecific Gravity Bone2.0 Muscle1.05 Cartilage1.1 Lipids Squalene0.86 end

2. Lift generated by swimming: lift thrust 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 DO hemoglobin plasma gaseous O 2 O2O2 O2O2 O2O2 gills blood rete water swim bladder How are high pressures achieved? end

Counter-current multiplication system afferent blood efferent blood O 2 heme  pO2pO2 O 2 heme   p O 2 pO2pO2 swim bladder O 2 heme   pO 2  lactic acid Bohr & Root 1 Diagram of basic functional unit of rete (inflation) end

Function of Rete Mirabile 1. Hemoglobin saturated with O 2 (O 2 heme) plasma O 2 low (p O 2 ) end

Counter-current multiplication system afferent blood efferent blood O 2 heme  pO2pO2 O 2 heme   pO 2 pO2pO2 swim bladder O 2 heme   pO 2  12 lactic acid end

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

Counter-current multiplication system afferent blood efferent blood O 2 heme  pO2pO2 O 2 heme   pO 2 pO2pO2 swim bladder O 2 heme   pO 2  lactic acid 12 3 end

Function of Rete Mirabile 3. Multiplying effect: pO 2 diffuses from efferent capillary to afferent cap. Longer capillaries yield more efficient exchange of oxygen, higher pressures end

O2O2 O2O2 1.Steady supply of oxygen in 2.Little or none leaves 3.PO 2 accum. in plasma 4.Diffusion into SB Summary of what happens to O 2 end

Physoclistous swim bladder Pressures up to 300 ATM in some deep sea fishes Gases mostly O 2, some CO 2 and N 2 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 O 2 ; controlled by structure & function Relationship O 2 bound to hemoglobin versus O 2 in plasma Effect of pH on affinity/capacity of hemoglobin for O 2 (Bohr & Root) Counter-current multiplier –length of capillaries –counter-current flow of blood end