Press "Enter" to skip to content

What happens to the A band in the sarcomere during muscle contraction?

What happens to the A band in the sarcomere during muscle contraction?

Figure 6.7. When (a) a sarcomere (b) contracts, the Z lines move closer together and the I band gets smaller. The A band stays the same width and, at full contraction, the thin filaments overlap. When a sarcomere shortens, some regions shorten whereas others stay the same length.

Is there any situation where the thick and thin filaments no longer overlap is there a situation where the thin and thick filaments are incapable of overlapping anymore?

4. Is there any situation where the thick and thin filaments no longer overlap? A situation where the thin and thick filaments are incapable of overlapping is when the muscle is completely contracted and there is no more space for the filaments to move.

What is the region of thin filaments that has no overlap with thick filaments called?

H zone. What is the region of thin filaments that has no overlap with thick filaments called? I band.

What occurs in the sarcomere when calcium is absent?

Once the myosin-binding sites are exposed, and if sufficient ATP is present, myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens and the muscle contracts. In the absence of calcium, this binding does not occur, so the presence of free calcium is an important regulator of muscle contraction.

What are 2 things that can affect strength of a muscle contraction?

Muscle strength is also a result of the combination of three factors:

  • Physiological strength, which depends on factors such as muscle size, the cross-sectional area of the muscle and responses to training.
  • Neurological strength, which looks at how weak or how strong the signal is that tells the muscle to contract.

Which is the direct source of energy for muscle contraction?

adenosine triphosphate (ATP)

What is the direct source of energy for cells?

Adenosine 5′-triphosphate, or ATP, is the most abundant energy carrier molecule in cells. This molecule is made of a nitrogen base (adenine), a ribose sugar, and three phosphate groups. The word adenosine refers to the adenine plus the ribose sugar.

Which nutrient is a direct source of energy for the body?

Carbohydrates are the main energy source of the human diet. The metabolic disposal of dietary carbohydrates is direct oxidation in various tissues, glycogen synthesis (in liver and muscles), and hepatic de novo lipogenesis.