1. Human Locomotion © Lisa Michalek

2. Locomotion  The interaction of muscles with the skeleton that results in body movement is known as locomotion.  Locomotion increases the chances for survival of an organism by allowing the organism to gather food, seek shelter, and escape dangerous situations.  Locomotion also increases the chances for survival of a species by enabling members of the species to find suitable mates.  Human locomotion involves the interaction of joints and tissues such as bone, cartilage, muscles, tendons and ligaments.

3. Bones  Bone is a type of connective tissue.  The hardness of the bone is due to the presence of calcium and phosphorus minerals.  Bones make up the major part of the framework of the human skeleton and come in many shapes and sizes.  Bones support and protect body organs.  Bones also provide a place for muscle attachment.

4. Bones  The bones of your legs and arms are called long bones.  The ends are covered with cartilage and are capable of growth.  Living bones contain living blood, fat, and bone cells.  Red and white blood cells are produced in the inner tissue, marrow, of bones.

5. Human Skeleton  The human skeleton acts as a framework for supporting other organs of the body.  It also protects internal organs and allows body movement.  The human skeleton has 206 bones.  It is composed of a skull, vertebral column (spinal column), breastbone and ribs, and limbs (arms and legs).

6. Cartilage  The fibrous, flexible, elastic connective tissue found in the human skeleton is cartilage.  In the human embryo, the skeleton is made up mostly of cartilage.  By adulthood, most of the cartilage has been replaced by bone.  In the adult, cartilage is found in the nose, ears, and trachea, at the ends of ribs and other bones and between the vertebrae.

7. Cartilage  At the ends of bones, cartilage provides flexibility.  Between bones, cartilage provides cushioning.  In the ears, nose, and trachea, cartilage provides flexible, rather than rigid support.

8. Joints  Bones are connected at places called joints.  Most joints allow bone movement.  Ball and socket joints are located at the hip and shoulder. They permit circular movement.

9. Joints  Hinge joints are located at the elbows and knees. They allow a back and forth movement. Hinge joints do not permit as much movement as ball and socket joints.

10. Joints  Pivot joints are found where the skull joins the vertebral column. Pivot joints permit a rotating movement.

11. Joints  The wrist and ankle have gliding joints that allow a sliding action.  Fused joints are not movable and are located in the skull.  Fluids in joints help keep joints cushioned and lubricated.

12. Muscles  The human body contains three kinds of muscle tissue: Skeletal muscle Smooth muscle And cardiac muscle  Muscles produce body movement by pulling on bones when they contract.  Muscles also produce body heat when they contract.  Muscles can be voluntary or involuntary.

13. Involuntary Muscles  Involuntary muscles are responsible for involuntary body activities such as heart contractions and peristalsis.  You cannot control the actions of involuntary muscles.  Smooth muscle and cardiac muscle are examples of involuntary muscles.

14. Involuntary Muscles  Smooth muscle is found in the walls of arteries and organs of the body. Contraction of smooth muscle is controlled by the nervous system.  Cardiac muscle, found in the walls of the heart, causes the heart to beat.

15. Voluntary Muscles  Voluntary muscles attach to the skeleton and can be controlled for locomotion.  Skeletal (striated) muscle is a type of voluntary muscle.  Striated muscles are attached to the bones of the skeleton.  The bones and body parts are moved by the contraction of these muscles.

16. Muscle Action  Nerves direct impulses to muscles causing them to contract.  The energy needed for the muscle to contract comes from energy stored in chemicals such as glycogen.  Muscle cells will continue to operate even if they do not receive sufficient oxygen.  When the muscle does not receive enough oxygen to carry on aerobic respiration, the muscle cells change to anaerobic respiration.

17. Muscle Action  During anaerobic respiration the muscle cells produce lactic acid.  Lactic acid causes muscles to hurt.  This condition is known as muscle fatigue.  Rest after exercise supplies oxygen to fatigued muscle cells.  During this rest-recovery period, the lactic acid is removed and energy-storing compounds are built up again.  If a person does not rest after muscle fatigue, permanent injury to the muscle can occur.

18. Tendons and Ligaments  Tendons and ligaments are both composed of connective tissue.  Tendons are bands of dense tissue that connect muscles to bones.  Ligaments are tough bands of tissue that hold bones together at joints.

19. Muscle-Bone Disorders  Fractures are broken bones. Fractures are caused by a sudden injury that exerts more force on the bone than it can support. The common symptom of a fracture is swelling and tenderness at the place of the fracture. Pain is often severe and is usually made worse by any movement of the area. Anyone suffering a suspected or known fracture should be taken to a hospital.

20. Muscle-Bone Disorders  Sprains A tearing or stretching of the ligaments that hold together the bone end in a joint is called a sprain. Sprains are caused by a sudden pull or twist. Because a sprain and a fracture have similar symptoms, the sprain should be x-rayed to be sure that it is not a fracture.

21. Muscle-Bone Disorders  Hernias In a hernia an organ or tissue sticks out through a weak area in the muscle or other tissue that usually contains it such as the abdominal wall. The cause is usually a weakness in the wall. The first symptom is a bulge in the wall.

22. Muscle-Bone Disorders  Arthritis An inflammation of the joints is called arthritis. Arthritis causes stiffness, swelling, soreness, or pain. Sometimes the joints stiffen in a deformed position. Cortisone and other medications are used in the treatment of arthritis.

23. Muscle-Bone Disorders  Tendonitis is an inflammation of a tendon, usually at the bone junction. Usually pain is felt in the wrist or ankle after extensive use such as running or even using a computer.

24. Other Muscle-Bone Disorders Scoliosis Osteoporosis