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Topic 13: Energetics & Performance
� How are gas exchange, circulation & metabolism inter-related?
� Gas Exchange� How is it done in air and water?
� What organs are involved in each case?
� How does ventilation differ among taxa?
� Circulation� What are the main components of circulation?
� How does circulation work?
� How does the anatomy of the heart differ among taxa?
� Metabolism� What are the different types of metabolic rates?
� What are the two types of metabolism?
� How is performance influenced by temperature?
How are gas exchange, circulation &
metabolism inter-related?
Mammalian circulation – ignore the detailsMammalian circulation – ignore the details
© McGraw-Hill
� What are the components of the gas exchange system?
� What are the components of the circulatory system?
� How are gas exchange, circulation & metabolism interrelated?
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How are gas exchange, circulation &
metabolism inter-related?
Mammalian circulation – ignore the detailsMammalian circulation – ignore the details
© McGraw-Hill
8/19/2013
1
Gas Exchange
� Two main purposes
� ______________ from environment to tissues
� ________________ from tissues
� Gas exchange occurs in both air and water
� “Reptiles” generally exchange gases in air
� Amphibians do this in both air and water
© R Tramontano, PJB
Ambystoma tigrinum
Gas Exchange
� Two types of structures for respiration
� ________________
� Lungs
� ________________
� Gills, skin, pharynx, cloaca
� Amphibians have many non-pulmonary gas exchange structures (also often lungs)
� Reptile have predominantly pulmonary gas exchange
Gas Exchange
� Non-pulmonary: Amphibians
� Gas exchange and water balance are related through same structures
� Gas exchange structures:
� ______________ – plethodontids
� ________ (cutaneous respiration)
� All amphibians
� Especially hellbender, hairy frog
� _____________
� All larval amphibians
� Paedomorphic adults
Stebbins & Cohen 1995, Fig. 3.5; EJ Routman
Gas Exchange
� Non-pulmonary: “Reptiles”
� Not prevalent because of keratinized skin
� Hydrophiinae (sea snakes)
� _____________________
� Some Testudines
� Rheodytes leukops, an Australian Pleurodire
� Has ________________ lined with villi
� Pump water in and out of bursae ~80 times/minute
http://www.divegallery.com/sea_krait.htm
Pough et al 2004, Fig 4-35
Gas Exchange
� Pulmonary – using lungs
� Widespread (obviously)
� Requires _______________ of the lungs� Exhalation of O2 poor, CO2 rich air
� Inhalation of O2 rich, CO2 poor air
� Most amphibians use _________________________
Liem et al. Fig. 18-14
Gas Exchange
� Pulmonary ventilation
� Lepidosaurs use _________________
� Expansion of thoracic cavity creates negative pressure �Inhalation
� In lizards, air moves between lungs during locomotion
� In snakes, pressure changes
� In _______________ lung where gas exchange occurs
� Not much in __________ part, where air is stored
Pough et al 2004, Fig 7-5, 7-6
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� Pulmonary ventilation
� Testudines have a rigid shell
� mm. transversus abdominis & pectoralis control size of
visceral cavity, facilitating ventilation
� Crocodylia use the liver
� m. diaphragmaticus pulls liver anteriorly
� This compresses lungs, leading to exhalation
Gas Exchange
Pough et al 2004, Fig 7-7
Circulation
� Components of the circulatory system� Heart
� Vessels (veins, arteries, capillaries)
� Blood
� The heart pumps the blood through the vessels to:� Lungs/gills
� Organs
� Muscles
� Transports _____________ & ___________ Mammalian circulation – ignore the details
© McGraw-Hill
Circulation
� Circulation pattern depends on gas exchange structure
� Gills (larval amphibians)
� ________________
� Heart � ___________ �___________ � Heart
� O2-poor blood goes to gills
� O2-rich blood goes to body
� Same as fishes
www.universe-review.ca
Circulation
� Lungs (most others)
� ___________________
� Heart � ___________ �Heart � ________ � Heart
� Pulmonary circuit has lower blood pressure than systemic circuit
� Variation in how heart is divided among taxa
www.universe-review.ca
Circulation
� _______________ arteries
� Paired vessels in adult amphibians
� Divide into:
� Pulmonary arteries
� Cutaneous arteries
� Skin is part of pulmonary circuit, provides:
� 20-90% O2 uptake
� 30-100% CO2 release
� What amphibians would
have almost all gas exchange through skin?
Photo © EJ Routman
Circulation
� Variation in heart morphology: Anura� 3 chambers
� _____________
� _____________
� Oxygenated and deoxygenated blood mix in heart!
� ______________ and channels formed by trabeculae help keep O2
rich and poor blood separate
� “Good enough” for slower metabolism
Pough et al 2004, Fig 7-8
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Circulation
� Variation in heart morphology: Testudines & Squamata
� 3 chambers (2 atria, 1 ventricle)
� Ventricle subdivided into 3 chambers:
Pough et al 2004, Fig 7-9
• _______________
• _______________
• _______________
• Atrioventricular valve blocks interventricular
canal between CA & CV
• Muscular ridge
divides CV & CP
O2 rich
O2 poor
Circulation
Pough et al 2004, Fig 7-10
O2 rich
O2 poor
� Variation in heart morphology: Crocodylia
� 4 chambered heart:
� _______________
� _______________
� Separation of pulmonary and systemic circuits
� _______________________ acts as a shunt
� Allows the movement of blood between circuits
Circulation
� What are shunts for?
� ______________________� Controlling [O2] affects pH� Can supply more oxygen to
tissues when animal is not breathing
� ______________________� Controlling amount of blood
in the systemic circuit affects heating and cooling rates
� ______________________� R�L shunt� Blood bypasses the lungs
during diving, etc.
Proceedings of the Royal Society
Metabolism
� The use of sugars to produce energy
� This energy is used for:� _______________
� Movement
� _______________
� Reproduction
� Anything else the animal does
� Sugars are transported to cells by _______________
� Sugars are metabolized in ____________
Photos © PJB, B Rourke
Metabolism
� Metabolic rate� Varies with activity
� ___________ metabolic rate
� Minimum energy consumption to stay alive
� Postabsorptive, inactive, inactive part of day
� ___________ metabolic rate
� Postabsorptive, inactive, but alert
� ___________ metabolic rate
� Maximal aerobic rate
� At cusp of switching to anaerobic metabolism
� Maximal O2 intake
Pough et al. 2004, Fig 7-11
Metabolism
� Maximum metabolic rate occurs at maximum aerobic speed (MAS)
� During sustainable activity� _______________________
_______________________
� Glucose is metabolized
� Water and CO2 are produced
� During unsustainable activity� _______________________
� Glycogen is metabolized
� Lactate is produced, leading to fatigue
Pough et al. 2004, Fig 7-11
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Metabolism
� All metabolism produces ATP, which is used as energy
� _____________________ is aerobic� 1 sugar � 35 ATP + CO2 +H2O
� Efficient, but slow
� Good for sustained activity
� _____________________ is anaerobic� 1 sugar � 3 ATP + Lactic Acid
� Inefficient but fast
� Good for short term, high output activity
www.palaeos.com
Metabolism
� Sceloporus jarrovii use glycolytic metabolism during territorial defense
� Routine activity� _____________
� Little ________ build up
� Territorial defense� Intense
� Includes running and biting other males
� ___________________
� [Lactate] proportional to# bites/minute
PJB; Pough et al. 2004 Fig 7-13
Metabolism
� Temperature affects performance in ectotherms
� Affects locomotion in Phelsuma dubia
� At high temps, they take ________________
� Stride duration is affected by how fast
muscles can __________________________
� Stride length is ________________________
Bergmann & Irschick 2006; Photo © PJB
10 15 20 25 30 35 40
Temperature (C)
-1.0
-0.5
0.0
0.5
Log m
ax velocity (m/s) a bab
Velocity
10 15 20 25 30 35 40
Temperature (C)
0
10
20
30
40
50
60
70
80
St ride Length (mm)
a ab b b
10 15 20 25 30 35 40
Temperature (C)
0.0
0.1
0.2
0.3
Stride Duration (s)
a dab bc cd
Stride Duration Stride Length
Metabolism
� Post-meal metabolism in snakes
� Digestion uses a lot of energy, especially when meal is big
� Some pythons consume ~10X more oxygen at peak digestion
Ott & Secor 2007
• Also, intestine of a fed snake:
• More blood
• More mucous
• Thicker intestinal lining
Time
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Metabolism
� Calling in frogs is also energetically expensive
� The higher the calling rate, the higher the metabolic rate
� Some call 1500X/hour
� V02 increases 10X
??; Pough et al. 2004, Fig 7-18
Metabolism
� Calling in frogs is energetically expensive…
� …but is it worth it?
Pough et al. 2004, Fig 7-19, 7-20
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