Which muscle type is involuntary and striated?

Cardiac muscle is indeed the muscle type that is both involuntary and striated. It is found only in the heart and is responsible for pumping blood throughout the body. The striations seen in cardiac muscle are due to the organized structure of the muscle fibers, which contain sarcomeres, similar to skeletal muscle. However, unlike skeletal muscle, which is under voluntary control, cardiac muscle functions automatically without conscious thought. This involuntary nature is essential for maintaining a continuous heartbeat and responding to the body's needs for oxygen and nutrients. The specialized cells in cardiac muscle, known as cardiomyocytes, are interconnected by intercalated discs, which facilitate rapid communication and coordinated contractions, further emphasizing its involuntary and rhythmic function in the circulatory system.