The Skeletal System Tuesday, February 2, 2010 Pages 480 -- 487 Chapter 15, Section 2 The Skeletal System Tuesday, February 2, 2010 Pages 480 -- 487

Objectives Identify the functions of the skeleton. Describe the structure of bones and how they grow and form. Explain the role of movable joints in the body. List ways that individuals can keep their bones strong and healthy.

Vocabulary Words Vertebra Marrow Cartilage Joint Ligament Osteoporosis

Function of the Skeletal System Five major functions: Provides shape and support Enables movement Protects internal organs Produces blood cells Stores certain materials until they’re needed by the body.

Skeletal System The human skeleton provides a framework that supports and protects many other body parts. The vertebral column is the center of the skeleton.

Skeletal System - cont’d The skeleton allows movement. The bones protect many of the organs in your body. Some bones produce substances needed by the body. Some bones store minerals such as calcium and phosphorus.

Bones Bones are alive. Bones are strong and lightweight. Only about 20 percent of an average adult’s body weight is bone. Bones contain cells and tissues.

Structure of Bones A thin, tough membrane covers all of the bone except for the ends. Blood vessels and nerves enter and leave the bone through the membrane. Compact bone is beneath the membrane.

Structure of Bones - cont’d Inside the compact bone is a layer of spongy bone. Spaces in the bone contain marrow, a soft connective tissue. 2 types of marrow: Yellow: stores fat which serves as an energy reserve. Red: produces the body’s blood cells.

Cartilage A connective tissue that is more flexible than bone. Hard bone tissue replaces cartilage over time. Cartilage covers the ends of many bones.

Skeletal Joints Joints is where two bones come together. Allows movement in different ways. Two kinds of joints: Immovable joints Movable joints

Immovable Joints Joints that connect but allow little or no movement. The bones in the skull and the joints that attach the ribs to the sternum are examples.

Movable Joints Most joints in the body are movable. Allows the body to make a wide range of movements. 4 types of movable joints: Ball and socket Hinge Pivot Gliding

Bone Health Healthy bones need a combination of a balanced diet and regular exercise. Osteoporosis is the condition in which the body’s bones become weak and break easily. Osteoporosis more common in women than in men.

Homework Workbook 15.2 (2/4) Vocabulary quiz 15.2 (2/4)