The Muscular System

Functions of muscles What comes to mind when you think of muscles? A muscle is made of strong tissue that contracts in an orderly way 4 main functions of muscles: Movement Stability Protection Temperature regulation

Movement Most of the muscles involved in moving the body work in pairs The skeletal and muscular system work together to help the body move Bones move when muscles contract or shorten Some movement can be fast (run) or slow (stretch) Muscles that aren’t attached to the skeleton contract to push blood and food through the body, as well as other things

Stability Muscles that are attached to bone also help with stability, balance, and posture The cordlike structures that you see moving under the skin are tendons, which attach muscle to bone Tendons help keep joints in place as well as help the body maintain its shape Most muscles are always contracted a little

The only time muscles that help maintain posture relax completely is when you are asleep Your muscles make constant adjustments to keep you sitting or standing upright automatically without you thinking about it

protection Muscles protect the skeleton and cover the majority of the organs in the body They offer layers of padding Muscles also surround the abdomen, chest, and back while also protecting the internal organs

Temperature regulation What does the body do when you are cold? When the body shivers, the muscles contract rapidly and change chemical energy to thermal energy (heat) which raises the body’s temperature In order for the body to function properly, it has to maintain a normal body temperature of 98.6°F Muscles contract, releasing heat to help the body maintain this body temperature

Skeletal muscles Skeletal muscles are those that attached to your skeleton; they are also called voluntary muscles you can consciously move them Pull on bones and must work in pairs Change throughout your lifetime and increase in size if you exercise

Cardiac muscle The heart is made of cardiac muscle is found only in the heart The cardiac muscle is involuntary, meaning you cannot consciously control it When they contract/relax, they pump blood through the body

Smooth muscles Smooth muscles line blood vessels and organs They are involuntary muscles named for their smooth appearance Contraction of smooth muscles helps push food through the stomach and control blood movement through the vessels

Sprain vs. strain