Respiration, Circulation and Metabolism Circulatory system Gills and Oxygen uptake Thermal...
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Transcript of Respiration, Circulation and Metabolism Circulatory system Gills and Oxygen uptake Thermal...
Respiration, Circulation and Metabolism
• Circulatory system• Gills and Oxygen uptake• Thermal regulation
ScombridaeBigeye tunaThunnus obesus
Deep Scattering Layer:
Diel Vertical Migrators
Circulatory System
Properties of Water Related to Exchange of
Gases•Water contains 1% O2 by volume, whereas air contains 21% O2 by volume
•Concentration of O2 dissolved in water varies inversely with temperature and salinity
•Salting out effect
•High water temperature = Low O2 concentration
•CO2 is very soluble in water because it undergoes partial disassociation and forms a weak chemical bond with water (H2O + CO2 = H+ + HCO3
- = H2CO3)
Ventilation and Respiration
• Aerobic RespirationO2 + CH2O CO2 + H2O + ENERGY
• Ventilation: process of directing oxygenated water
through blood capillary beds
• Diffusion: Passive transport of O2 from water across epithelial cells and into the capillaries containing blood
CH2O Lactate + energy ANAEROBIC RESPIRATION
Lamprey Shark Teleost
Ventilation: unidirectional flow of water.
Counter current flow between blood and water maximizes exchange between fluids.
Gill Lamella
•If fluids flowed in same direction exchange would be about 50%, regardless the length of the flow systems.
•With counter current flow exchange is more complete and varies directly with length of the flow systems.
Counter current systems
Thermal regulation: control of body
temperatureBody temperature of animals
relative to that of the environment– Poikilotherms– Homeotherms
Source of animal’s body heat– Ectotherms– Endotherms
Mechanisms of thermal regulation in fishes
• behavioral• physiological (endothermy)
Behavioral thermoregulation
LamnidaeMako Isurus oxyrinchus
Physiological thermoregulation (endothermy)
AlopiidaeThresher sharkAlopias superciliosus
Physiological thermoregulation (endothermy)
ScombridaeBigeye tunaThunnus obesus
Physiological thermoregulation (endothermy)
Forms of Endothermy
• Systemic or whole body endothermy– Lamnidae, Alopiidae, Scombridae
• Regional endothermy refers to
maintaining elevated temperatures only in certain parts of the body: – cranial endothermy (“brain heaters”)– Istiophoridae, Xiphiidae
Cranial endothermy (“brain heaters”):•Billfishes (Istiophoridae)
XiphiidaeSwordfishXiphias gladius
Cranial endothermy (“brain heaters”):
Systemic (whole body) endothermy
Shared presence of:streamlined bodynarrow caudal pedunclecrescent-shaped caudal fin
Block et al. 2002
Atlantic Bluefin tuna (Thunnus thynnus)
Muscle Temp = 28 – 30 oC / Water temperature = - 20 oC
ScombridaeBigeye tunaThunnus obesus
Deep Scattering Layer:
Diel Vertical Migrators
Structures and functions involved in systemic
endothermy• Distribution of blood vessels• Distribution of red muscle (used for
sustained swimming, heat generating)
• Rete mirabile (heat exchanger)
Distribution of blood vessels
Ectotherm
Endotherm
Distribution of red muscle and blood vessels in cross-section
Ectotherm Bluefin tuna
Skipjack tuna Mako shark
Red muscle
Distribution of red muscle and blood vessels in cross-section
Ectotherm Bluefin tuna
Skipjack tuna Mako shark
Red muscle
Heat exchanging retia mirabile of tuna.