Final answer:
Skeletal muscles have characteristics such as being rich in myoglobin, storing glycogen, using both aerobic and anaerobic respiration, and contracting voluntarily. They contain different types of fibers like SO, FO, and FG, with varying contraction speeds and metabolic processes. Additionally, they are essential for movement, maintaining posture, stabilizing joints, and thermal regulation.
Step-by-step explanation:
The characteristics of skeletal muscles are that they are rich in myoglobin, have large stores of glycogen, use aerobic respiration as well as anaerobic processes, and contract voluntarily. Skeletal muscles, which make up a significant portion of our body mass, facilitate movements such as walking, facial expressions, and maintaining posture. Crucially, they are controlled by thought, meaning that most of their actions are voluntary; however, they can contract involuntarily through reflexive actions in response to stimuli, such as the reflex that occurs when you touch something hot.
Skeletal muscle fibers differ in their contraction speeds and ATP production methods. There are three main types: Slow oxidative (SO) fibers, which contract slowly and rely on aerobic respiration; Fast oxidative (FO) fibers, which contract quickly and primarily use aerobic respiration but can switch to anaerobic respiration when needed; and Fast glycolytic (FG) fibers, which contract quickly and primarily use anaerobic glycolysis. Most skeletal muscles contain a mix of all three fiber types, allowing for various functions and responses.
Skeletal muscles also contribute to thermal homeostasis by generating heat during contraction and play a role in maintaining posture and stabilizing joints. Under a microscope, skeletal muscle tissue appears striated due to the arrangement of contractile proteins actin and myosin, and it typically has multiple nuclei due to the fusion of myoblasts during development.