# Muscles (General) Muscles are biological contractors responsible for movement and pumping blood. Muscles work by either contracting or relaxing to cause movement. This movement may be voluntary or done without our conscious awareness. # Types of Muscles There are three types of muscles: - **==Skeletal Muscle==** (attached to the bones, responsible for skeletal movements) *dt. Skelettmuskulatur, Quergestreifte Muskeln* - **==Smooth Muscle==** (found in the walls of the hollow internal organs such as blood vessels) *dt. Organmuskulatur, Glatte Muskeln* - **==Cardiac Muscle==** (found in the walls of the heart) *dt. Herzmuskulatur* # Voluntary and Involuntary Muscles Additionally, there are: - **==Voluntary Muscles==** Make up 40% - 50% of the human body's weight. These are skeletal muscles that contract and relax under conscious control. These muscles attach to bones and regulate movement of the body. ^[https://www.verywellhealth.com/voluntary-muscles-5199032#:~:text=Voluntary%20muscles%20are%20skeletal%20muscles,are%20not%20under%20conscious%20control.] - **==Involuntary Muscles==** Smooth muscles, which are not under conscious control. They contract and relax automatically and receive signals from the autonomic nervous system, which regulates your internal bodily functions. ^[https://www.verywellhealth.com/voluntary-muscles-5199032#:~:text=Voluntary%20muscles%20are%20skeletal%20muscles,are%20not%20under%20conscious%20control.] >[!info] >The heart can be seen as an exception, as it is striated like a skeletal muscle, but is controlled by both the autonomic nervous system and its own pacemaker cells, making it an involuntary muscle. # Tendons *dt. Sehnen* Tendons are fibrous connective tissues that attach muscles to bones. The largest tendon of the human body is the ***achilles tendon*** *(connects the calf muscle to the heel bone)*. ## Fascia Fascia connects "muscle to muscle". ## Aponeuroses *dt. Aponeurose* Aponeuroses are flat sheets of connective tissue in the body that are similar to tendons. They cover muscles and help connect muscles to bones and cartilage.^[https://my.clevelandclinic.org/health/body/23407-aponeurosis]