Which type of muscle is involuntary and functions to pump blood?

Cardiac muscle is the type of muscle that is involuntary and specifically functions to pump blood throughout the body. This muscle makes up the walls of the heart and is unique due to its branching structure and intercalated discs, which allow for synchronized contractions. The involuntary nature of cardiac muscle means it operates without conscious control, managed instead by the autonomic nervous system. This is essential for maintaining the heartbeat and ensuring an adequate blood supply to meet the body's needs.

Skeletal muscle, while striated like cardiac muscle, is under voluntary control and is responsible for movements of the skeleton. Connective tissue does not have muscular properties and does not contract to produce movement. Striated muscle refers broadly to muscles with a banded appearance, which includes both skeletal and cardiac muscle, but it does not specify the involuntary function of pumping blood.