Final answer:
Skeletal muscles are organs made of skeletal muscle cells, which possess the unique feature of contractility, allowing for voluntary movement and locomotion; they also assist in regulating body temperature.
Step-by-step explanation:
Skeletal muscles are organs formed by skeletal muscle tissue, and the tissue is made up of skeletal muscle cells. Skeletal muscle tissue is a type of muscle tissue that has the unique ability to contract, or become shorter, enabling the body to move. This tissue is composed of long and cylindrical cells known as myocytes, which are multinucleate (having multiple nuclei). These cells exhibit a striated appearance under a microscope, revealing a regular alignment of the contractile proteins actin and myosin that are responsible for muscle contraction.
Additionally, skeletal muscle tissue is connected to bones, sometimes to the skin, and controls voluntary movement and locomotion. It is called voluntary muscle because it can be controlled consciously. The importance of skeletal muscles extends beyond movement, as they also participate in thermal homeostasis through the generation of heat, especially noticeable when shivering occurs in response to cold temperatures.