NEET BIOLOGY

Detailed explanation-1: -Contracting muscle consumes large amounts of oxygen to replenish ATP that is hydrolyzed during contraction; therefore, contracting muscle needs to increase its blood flow and oxygen delivery to support its metabolic and contractile activities.

Detailed explanation-2: -First, because the metabolic costs of muscle contraction can be high and prolonged, skeletal muscle blood flow needs to be matched to the metabolic demands of the contracting muscles. Second, regulation of blood pressure is also needed to ensure there is adequate perfusion pressure to all organs.

Detailed explanation-3: -Adenosine triphosphate (ATP) is the sole fuel for muscle contraction. During near maximal intense exercise the muscle store of ATP will be depleted in < 1s, therefore, to maintain normal contractile function ATP must be continually resynthesized.

Detailed explanation-4: -ATP is critical for muscle contractions because it breaks the myosin-actin cross-bridge, freeing the myosin for the next contraction.

Detailed explanation-5: -Aerobic respiration requires the presence of oxygen to break down food energy (usually glucose and fat) to generate ATP for muscle contractions. Aerobic respiration produces large amounts of ATP and is an efficient means of making ATP.