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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; 10-15 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
TissuesGills
blood circulation
pH lowerpH higher
pCO2 higherpCO2 lowerlactic acidno lactic acid
end
pH?
pCO2?
lactic acid?
Teleost Heart:
sinus venosusatrium
ventricle
bulbus arteriosus
end
Teleost Heart:
sinus venosusatrium
ventricle
bulbus arteriosus
endrelax
Teleost Heart:
sinus venosusatrium
ventricle
bulbus arteriosus
endcontract
Conus arteriosus--Myxini, Ceph., elasmobranchs, gar
heartto gills
end
time
Pre
ssur
e (m
m m
erc.
)
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
Substance Specific GravityBone 2.0Muscle 1.05Cartilage 1.1Freshwater 1.002 @20CSaltwater 1.072 @20CLipids 0.9-0.92Squalene 0.86
end
2. Lift generated by swimming:
lift
lift
thrust
sharks Advantages/disadvantagesend
hammerhead shark
end
nurse shark
end
sandbar shark
end
3. Reduction of heavy tissues
Eurypharynx pelecanoides
deepwater fishes
Advantages/disadvantagesend
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 O2O2 O2
O2
gills
blood
rete
water swim bladder
How are high
pressures achieved?
end
Counter-current multiplication system
afferent blood
efferent blood
O2hemepO2
O2heme pO2
pO2
swim
bla
dder
O2heme pO2
lactic acidBohr & Root
1
Diagram of basic functional unit of rete(inflation)
end
Function of Rete Mirabile
1. Hemoglobin saturated with O2 (O2 heme)
plasma O2 low (p O2)
end
Counter-current multiplication system
afferent blood
efferent blood
O2hemepO2
O2heme pO2
pO2
swim
bla
dder
O2heme pO2
1 2
lactic acid
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
afferent blood
efferent blood
O2hemepO2
O2heme pO2
pO2
swim
bla
dder
O2heme pO2
lactic acid
1 2
3
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
O2O2
1. Steady supply of oxygen in
2. Little or none leaves
3. PO2 accum. in plasma
4. Diffusion into SB
Summary of what happens to O2
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 (Bohr & Root)
• Counter-current multiplier– length of capillaries
– counter-current flow of blood
end