lihassäieillä
Lihassäieillä, also known as muscle fibers, are the fundamental cellular units of muscle tissue in vertebrates and invertebrates. These elongated cells are specialized for contraction, enabling movement. In vertebrates, there are two main types of lihassäieillä: slow-twitch (Type I) and fast-twitch (Type II). Slow-twitch fibers are efficient at aerobic respiration and are suited for endurance activities, characterized by their red appearance due to high myoglobin content. Fast-twitch fibers, on the other hand, are more powerful and contract quickly, relying on anaerobic glycolysis, and are typically white.
Within a lihassäie, the contractile elements are myofibrils, which are composed of repeating units called sarcomeres.
The arrangement and proportion of slow-twitch and fast-twitch lihassäieillä vary depending on the muscle's function and