Topic 4

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  • Created by: rfraser96
  • Created on: 18-04-17 09:35
How is lactate produced during exercise utilised? (2 marks)
Oxidation: Used as a fuel by neighbouring muscle fibres and other tissues, readily converted to pyruvate, enters Krebs cycle. Transport: via MCTs, type 1 fibre import La, type 2 fibre export La. Gluconeogenesis: Formation of new glucose, cori cycle
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What is the definition of lactate threshold? (4 marks)
The work rate above which blood lactate concentration consistently exceeds the resting value. Resting lactate concentration ~1mmol/l. Rate of production exceeds rate of utilisation
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What is the source of H+ in metabolic acidosis? (1 mark)
H+ released during ATP hydrolysis
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How do H+ cause fatigue? (3 marks)
In anaerobic metabolism, H+ from ATP hydrolysis are buffered. Eventually H+ will accumulate and cause metabolic acidosis followed by fatigue. Enzyme inactivation (slows down glycolysis), displacement of Ca2+ from cross bridges
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What exercise protocol would be used to determine lactate threshold invasively? (3 marks)
-Fingertip or earlobe capillary blood sample; Lactate threshold recorded as the last work rate before lactate concentration increases above baseline (pH?). Running speed vs blood lactate AND heart rate graph
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What is critical power? (4 marks)
Highest work rate that can be sustained without a continued increase in lactate
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How would you define moderate, heavy and very heavy intensities of exercise? (4 marks)
Moderate: Below lactate threshold. Heavy: Above lactate threshold but below critical power. Very heavy: Above critical power
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What exercise protocol would be used to determine lactate threshold non-invasively?
Analysis of expired air - point of "excess" CO2 used to estimate lactate threshold. Ramp protocol
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What are the physiological adaptations to endurance training?
Increase in mitochondrial size and number; Increase in oxidative enzymes; Increase in MCTs; increase in other enzymes (pyruvate dehydrogenase); Increased reliance on fat utilisation; LESS ACCUMULATION OF H+
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Card 2

Front

What is the definition of lactate threshold? (4 marks)

Back

The work rate above which blood lactate concentration consistently exceeds the resting value. Resting lactate concentration ~1mmol/l. Rate of production exceeds rate of utilisation

Card 3

Front

What is the source of H+ in metabolic acidosis? (1 mark)

Back

Preview of the front of card 3

Card 4

Front

How do H+ cause fatigue? (3 marks)

Back

Preview of the front of card 4

Card 5

Front

What exercise protocol would be used to determine lactate threshold invasively? (3 marks)

Back

Preview of the front of card 5
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