The skeletal system Chapter 15, lesson 2

Health concepts Bones have four primary functions. The skeleton gives structure and stability to the body. Eating well is one of the keys to maintaining the health of the skeletal system.

Functions of the skeletal system The skeleton plays a crucial role in movement by providing a strong, stable, and mobile framework on which muscles can act. It also supports and protects your delicate internal organs.

Structure of the skeleton The skeletal system is divided into two main parts: Axial skeleton- the 80 bones of the skull, spine, rubs, and sternum, or breastbone. Appendicular skeleton- includes the 126 bones of the shoulders, arms, hands, hips, legs, and feet.

Types of bones Bones are grouped according to their shapes. There are four basic types in the human body: long, short, flat, and irregular. Strong long bones, like the femur are found in the arms and legs. Diaphysis- the shafts of long bones. Epiphyses- form joints with other bones. Short bones, like those in the wrists and ankles, are as broad as they are long. Flat bones, like the ribs and skull bones, have a thin, flat shape. Irregular bones, like vertebrae, have a shape that does not fit into any of the other three categories.

Types of bones

cartilage Cartilage- a strong, flexible connective tissue. Ossification- the process by which bone is formed, renewed, and repaired.

joints Joints- the point where two bones meet. Types of joints Ball and socket joints- allows the widest range of movement: backward, forward, sideways, and in a circle. Examples: Shoulder and hip joint. Pivot Joint- a bony projection allows rotation. Examples: the first two vertebrae in the neck that allows your head to rotate. Ellipsoidal Joint- an oval shaped part fits into a curved space and allows all types of movement except pivotal. Example: Wrist. Hinge Joint- allows bending and straightening. Examples: Fingers, knee and elbow.

Joints

joints At joints where movement occurs, the surfaces of the bones are coated with smooth, slippery cartilage to reduce friction. Ligaments are tough bands of fibrous, slightly elastic tissue that bind the bone ends at the joint. In addition, ligaments prevent excessive movement of the joint. Tendons are fibrous cords that join muscle to bone or to other muscles.

Care of the skeletal system Your habits and decisions concerning nutrition and exercise affect the health of your skeletal system now, and later in life. Calcium, in milk for example, is essential for building strong bones. It is especially important during teen years when your body builds most of its bone mass. Regular physical activity, especially weight lifting exercises increase bone mass.

Problems of the skeletal system Fractures, Osteoporosis, Scoliosis & Joint Injuries Fractures are any type of break in a bone. 2 types: simple (aka “closed”) fractures – the bone does not stick out of the skin. compound (aka “open”) fractures – one or both bone ends project through the skin. Fractures may also be classified according to the shape or pattern of the break

Hairline fracture The fracture is incomplete, and the two parts of the bones do not separate.

Transverse fracture The fracture is completely across the bone. This may be the result from a sharp, direct blow or stress.

Comminuted fracture The bone shatters into more than two pieces, usually from sever force as in an auto accident.

Osteoporosis A condition in which bone density decreases, causing bone to become brittle and easily fractured. Women are especially vulnerable after menopause (no longer produce estrogen). Adequate calcium in the diet during teen years can prevent osteoporosis later in life.

Scoliosis Lateral, or side-to-side, curvature of the spine. Usually starts during childhood and becomes more marked until the age at which growth stops. School screenings. Treatment may include exercise, special brace, or surgery.

Joint injuries Dislocation Torn Cartilage Bunion Bursitis Arthritis Repetitive Motion Injury

Dislocation Results when a bone slips from its normal position at a joint. It is usually accompanied by tear of the joint ligaments. Never attempt to replace a dislocated bone on your own. Seek medical attention.

Torn cartilage Can result from a sharp blow or sever twisting of a joint. Doctors can now repair some cartilage tears with arthroscopic surgery.

Bursitis Painful condition that occurs when the bursa in a joint becomes inflamed. Common in the shoulder and knee. Usually the result of friction or pressure.

Bunion Painful swelling of the bursa in the first join of the big toe. Caused by wearing tight or high-heeled shoes.

Arthritis Inflammation of a joint, characterized by swelling, pain, stiffness, and redness. Most common type is osteoarthrosis, which results from wear and tear on the joints and most commonly troubles older adults.

Repetitive motion injury Damage to tissues caused by prolonged, repeated movements. Occurs when the same motion is performed hours at a time. Carpal tunnel syndrome is a common type Results from pressure on the median nerve where it passes through a gap known as the “carpal tunnel” under a ligament at the front of the wrist.

Homework Define 15.2 health terms… Bones of the body worksheet