State the position and role of the pituitary gland.
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Located in the brain below the hypothalamus
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Main endocrine gland that influences other glands
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Secretes hormones (ADH/GH/TSH/ACTH/oxytocin)
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Responsible for homeostasis/regulates bodily functions including growth, water retention, and temperature
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Describe excess post-exercise oxygen consumption (EPOC) and its role during the recovery phase.
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EPOC occurs as elevated breathing continues until recovery is complete
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EPOC repays the oxygen deficit created during initial anaerobic energy production
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Required for reformation of phosphocreatine stores
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Required for replenishment of myoglobin stores
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Required for removal/breakdown of lactic acid
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Required for replenishment of glycogen stores (can take up to 24 hours)
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Either:
- Highly trained aerobic athletes return to steady state more quickly than untrained individuals OR
- Highly trained aerobic athletes have a smaller EPOC than untrained individuals
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Describe how cardiovascular drift takes place.
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Cardiovascular drift is an increase in heart rate during prolonged exercise despite effort remaining the same
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During prolonged exercise there is an increase in core temperature
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The rise in core temperature causes redistribution of blood to the periphery for cooling
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The blood volume redistribution causes the heart to work harder to maintain muscle blood flow and energy demands
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Blood flow to skin increases and water is lost via sweating
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Prolonged cooling/sweating causes a decrease in blood volume and increase in viscosity
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Reduction in venous return/stroke volume causes heart rate to increase to maintain cardiac output
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Explain the chemical control of ventilation during exercise.
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Ventilation is chemically regulated by blood acidity levels/low pH
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Blood acidity levels increase/pH drops due to an increase in carbon dioxide levels
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Blood acidity levels are detected by chemoreceptors
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Medulla oblongata/ANS/respiratory control centre receive information from receptors
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Increased blood acidity (and information from the proprioceptors) increases the depth/rate of ventilation
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Analyze the physiological factors that contribute to peripheral fatigue during long-distance running.
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Depletion of muscle and liver glycogen reserves reduces energy source for ATP production
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Reduction in Ca release reduces muscle ability to perform muscle contraction
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Depletion of acetylcholine decreases effectiveness of muscle contraction
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Dehydration decreases effectiveness of waste product removal
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Electrolyte loss causes decreased nerve function and can cause cramping
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Overheating causes decreased muscle function as enzymes work best at normal body temperature conditions
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Increased peripheral fatigue takes place with unusually high intensity/lower VOmax
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