Tissue structure and function Flashcards
Explain why fast-twitch glycolytic muscle fibers fatigue more quickly than slow-twitch fibers.
Fast-twitch glycolytic fibers rely on anaerobic respiration, which generates lactic acid as a by-product, leading to rapid fatigue. Additionally, these fibers lack an extensive blood supply and have fewer mitochondria, limiting sustained energy production.
Describe the role of myoglobin in slow-twitch muscle fibers and explain how it supports endurance activities.
Myoglobin binds and stores oxygen in slow-twitch fibers, ensuring a steady supply of oxygen for aerobic respiration. This supports the production of ATP over long periods, making it essential for endurance activities like long-distance running.
Compare the adaptations of slow-twitch and fast-twitch muscle fibers for energy release. Include details of respiration type and the organelles involved.
Slow-twitch fibers use aerobic respiration, requiring a large number of mitochondria and an extensive capillary network to produce ATP efficiently. In contrast, fast-twitch fibers rely on anaerobic respiration, using glycogen reserves to produce energy quickly but in limited amounts.
An athlete is training for a 100m sprint event. Explain why fast-twitch fibers are crucial for their performance and how their properties align with this type of activity.
Fast-twitch fibers contract rapidly and with high force, making them ideal for short bursts of power required in a 100m sprint. Their reliance on anaerobic respiration allows for quick energy release without the need for oxygen, which suits the brief, high-intensity effort.
A researcher observes that a muscle sample contains a high density of capillaries and mitochondria. Deduce whether this muscle is predominantly composed of fast-twitch glycolytic or slow-twitch fibers, and justify your answer.
The muscle sample is likely from slow-twitch fibers due to the high density of capillaries and mitochondria. These features are necessary for aerobic respiration, which supports endurance activities.
Why do slow-twitch fibers appear red in color, and what is the physiological significance of this feature?
Slow-twitch fibers appear red due to their high myoglobin content, which binds oxygen. This oxygen storage enhances aerobic respiration, allowing for sustained energy production during prolonged activity.
Explain how the low myoglobin content in fast-twitch glycolytic fibers influences their ability to perform anaerobic respiration.
The low myoglobin content in fast-twitch fibers limits their oxygen storage, meaning they primarily rely on anaerobic respiration. This adaptation suits activities requiring quick energy bursts rather than prolonged endurance.
Discuss how the structure and function of blood supply in slow-twitch fibers contribute to the prevention of fatigue during endurance activities.
The dense capillary network in slow-twitch fibers ensures a continuous supply of oxygen and nutrients while removing waste products like carbon dioxide. This supports prolonged aerobic respiration, preventing fatigue during endurance activities.
In what ways do the structural and functional differences between fast-twitch glycolytic and slow-twitch fibers affect an individual’s suitability for particular sports? Provide examples to support your answer.
The rapid contraction speed and anaerobic energy release of fast-twitch fibers make them ideal for sports requiring short, explosive efforts like sprinting and weightlifting. Slow-twitch fibers, with their high endurance and aerobic capacity, are better suited for endurance sports such as marathon running or cycling.
Which type of muscle fiber has the least endurance and fatigues quickly?
Fast-twitch glycolytic fibers.
What type of respiration do fast-twitch glycolytic fibers primarily rely on?
Anaerobic respiration.
Why do slow-twitch fibers have a high number of mitochondria?
To produce large amounts of energy (ATP) through aerobic respiration over a long period.
What is the main function of myoglobin in slow-twitch fibers?
Myoglobin stores oxygen in the muscle, supporting aerobic respiration.
Which type of muscle fiber is better suited for marathon running?
Slow-twitch fibers.
What is the color of fast-twitch glycolytic fibers, and why?
They are white in color because they have little myoglobin.
