Skeletal and Muscular Systems Skeletal System Functions Gives

Skeletal and Muscular Systems

Skeletal System

Functions • Gives structure to the body • Supports Muscles • Protects organs

Organs • There are 206 bones in the body. • Layers of bone: – Periosteum – bone membrane – Compact Bone – hard part of the bone that provides support. – Spongy Bone – framework of the bone that makes bone light and strong. – Bone Marrow – produces blood cells and stores energy.

Bone Structure Periosteum Marrow Bony layer Blood vessels

Structures • Joint – place where bones are connected • Ligament – tough bands of tissue that hold joints together. • Tendon – cords that connect muscle to bone

How It Works • Muscles are connected to bones. When they cross a movable joint, they act to move it. • Types of Joints – Ball-and-socket Joint= shoulder and hip – Pivot Joint = top two vertebrae and elbow – Hinge Joint = knee and elbow

Muscular System

Function • Movement of the body • Protection of the joints • Heat creation

Organs • Muscles are made up of long paired strands of proteins. • Types of muscles – Skeletal Muscle – voluntary muscle that moves the body. – Smooth Muscle – involuntary muscle that lines internal organs; found in digestive tract and blood vessels. – Cardiac Muscle – muscle that is specific to the heart.

How It Works • Muscle can only contract and relax. Joints are moved by shortening muscles. • Muscles work in tandem. This is called reciprocal innervation. One muscle contracts on one side of the joint while the muscle on the other side relaxes.