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The diagram shows capillaries carrying blood through muscle - Edexcel - GCSE Biology - Question 2 - 2017 - Paper 1
Question 2
The diagram shows capillaries carrying blood through muscle. (a) Complete the sentence by putting a cross (X) in the box next to your answer. The blood vessel that... show full transcript
Worked Solution & Example Answer:The diagram shows capillaries carrying blood through muscle - Edexcel - GCSE Biology - Question 2 - 2017 - Paper 1
Step 1
Step 2
Explain how the concentration gradient is maintained between the blood and muscles.
Answer
The concentration gradient is maintained due to the continuous consumption of oxygen by the muscle cells during respiration. As oxygen is used up by the muscles, the concentration of oxygen in the muscle decreases, creating a gradient that facilitates the diffusion of oxygen from the blood (high concentration) to the muscle cells (low concentration). Additionally, the constant flow of blood through the capillaries helps to ensure that oxygen-rich blood keeps arriving, maintaining the difference in concentration.
Step 3
Step 4
Describe the relationship between cardiac output and running speed.
Answer
As running speed increases, cardiac output increases. The relationship is linear up to approximately 12 or 16 km/hr, where cardiac output rises significantly. Beyond this speed, the rate of increase in cardiac output becomes less pronounced.
Step 5
Explain why this runner gets muscle cramp when he runs at speeds over 24 km per hour.
Answer
The runner experiences muscle cramps when running at speeds over 24 km/h due to anaerobic respiration at high intensity. At such speeds, the muscles demand more energy than can be supplied efficiently through aerobic pathways, leading to the buildup of lactic acid. This accumulation can disrupt muscle function, leading to cramps and fatigue.