Skeletal, Muscular, and Nervous System Chapter 15 Lesson 1
With its highly engineered joints, the living skeleton provides a framework of stiff levers and stable plates that permits a multitude of movements. Intimately connected with the muscular system, the skeleton also integrates functionally with the cardiovascular system-every second millions of fresh blood cells pour out of the bone marrow. A healthy diet that provides enough minerals, especially calcium, along with regular moderate exercise can reduce the risks of many bone and joint disorders.
Skeletal System In this unit we will discuss the 4 main functions of the skeletal system. Movement Protection Cell Production Mineral Storage
Movement The skeletal system plays a crucial role in movement by providing a strong, stable, and mobile framework on which muscles can act. When muscles contract they pull on bones that are attached by tendons.
Tendons • Tendons are tough, fibrous cords of connective tissue that link skeletal muscles to bones.
Protection Your skeletal system protects many vital organs in your body. Example: Your skull bones protect brain tissue from possible damage due to impact
Cell Production Bone Marrow is found in flat bones like the sternum, vertebrea, skull, ribs, and hip bone, and at the ends of long bones. This marrow produces red and white blood cells as well as platelets.
Bone Marrow Bone marrow is soft, fibrous, blood –forming tissue that fills the inner cavities of bones. It produces many types of cells. Platelets always circulate in our bloodstream, looking for tiny tears in blood vessels where blood might leak out, like a paper cut. They accumulate in such cuts during clotting. Red blood cells carry fresh oxygen from the lungs to all the cells that need it, and then carry away the unneeded carbon dioxide. White blood cells are immune responders that combat foreign microorganisms. Those invaders might cause infection, so white blood cells help produce antibodies that keep the invaders from causing damage.
Storing Minerals Bones store minerals such as calcium and phosphorus. Calcium is "the most abundant mineral in the body." It is necessary for many bodily functions, including "muscle contraction, blood vessel expansion and contraction, secretion of hormones, etc.
Structure of the Skeleton • Your skeletal system consists of 206 bones that can be classified in two main groups.
Axial Skeleton The axial skeleton consists of the 80 bones of the skull, spine, ribs, vertebrae, and sternum.
Appendicular Skeleton The appendicular skeleton is composed of the remaining 126 bones that are not part of the Axial skeleton Examples: Upper and lower limbs, shoulders, and hips.
Long Bones • Examples of long bones include the bones in your legs and arms. • The main column of a long bone is called a diaphysis. Within the diaphysis is a narrow cavity that contains yellow bone marrow, a type of tissue that stores fat. • The end of a long bone is called the epiphysis. The epiphyses form joints with other bones and contain red bone marrow, where new blood cells are produced.
Short Bones • Short bones are almost equal in length and width. • Examples: Small bones in the wrist and ankle.
Flat Bones Flat bones are somewhat thinner and much flatter the other bones. Examples: Scapula and skull bones.
Cartilage Cartilage is a strong, flexible connective tissue. It plays a vital role in your skeletal system. It provides structure and support to the body's other tissues without being as hard or rigid as bone. It can also provide a cushioning effect in joints. There are several types of cartilage including…
Skeletal Growth An embryo’s skeleton consists mostly of cartilage that serves as a template from which bones will form. Early in embryonic development, the cartilage hardens, this is called ossification. Ossification: the process by which bone is formed, renewed, and repaired.
Joints • Joints are points at which bones meet. Some joints move, and other joints don’t. • The more flexible joints are classified by type.
Ball and Socket Joints • Ball and socket joints are formed when the rounded head of one bone fits into the rounded cavity of an adjoining bone. These joints allow the widest range of motion. • Examples: Hip or shoulder joints.
Hinge Joints • Hinge joints are found at the elbow, knee, ankle, and fingers. These joints are like door hinges, they don’t have as much range of motion as the ball and socket joints.
Pivot joints • Pivot joints allow limited rotation or turning of the head.
Ellipsoidal & Gliding Joints • Ellipsoidal joints have an oval-shaped part that fits into a curved space. • Gliding joints allow bones to slide over one another.
Caring for the Skeletal System Chapter 15 Lesson 2
Care of the Skeletal System • Caring for your skeletal system is something you can do every day. Eating foods that contain calcium, vitamin D, and phosphorus can help prevent the development of certain skeletal disorders.
Care of the skeletal system • Regular physical activity, including weight-bearing exercise, helps keep bones strong.
Fractures • A fracture is any type of break in a bone. Different names are given to fractures because of the way the bone breaks. • Hairline fracture • Transverse fracture • Comminuted fracture
Osteoporosis • Osteoporosis is a condition in which progressive loss of bone tissue occurs. • Bones are weakened and become brittle, causing them to break easily.
Scoliosis • Scoliosis is a lateral, or side to side, curvature of the spine. • The curvature of the spine worsens as growth continues and may proceed even after growth stops. • Treatment includes wearing a brace to help straighten the spine and, possible corrective surgery.
Bursitis • Bursitis results from the inflammation of a fluid-filled sac called the bursa. • Certain joints, such as the elbow, have bursae that help reduce friction between their movable parts.
Bunions • A bunion is a bone deformation that causes the big toe to protrude out rather than pointing straight ahead. • Because of the irregular shape extra pressure is placed on the bursa of the big toe, causing inflammation and pain • Wearing comfortable shoes may help prevent a bunion from developing.
Arthritis • Arthritis is the inflammation of a joint. The condition can result from an injury, natural wear and tear, or autoimmune disease. • The most common form of arthritis, osteoarthritis, results from wear and tear on the joints.
Repetitive Motion Injury • A repetitive motion injury is damage to tissues caused by prolonged, repeated movements such as in computer work, sewing, or assembly line work. • One of the most common repetitive motion injuries is carpal tunnel syndrome.
The muscular system Chapter 15 Lesson 3
Functions of the Muscular System • Muscles not only aid the skeletal system with movement and protection, it also helps with many of the body's processes. (Breathing, heart beat, digestion, etc.)
Who has control? Involuntary Voluntary Voluntary muscles get messages sent from the brain to control their contraction and relaxation. • Involuntary muscles are those muscles which are not under the control of the will. You don’t consciously think about digesting food, or making your heart beat, or breathing.
Smooth Muscle • Smooth muscles act on the lining of passageways and internal organs. • Smooth muscles can be found in the lining of the blood vessels, the digestive tract, the passageways that lead into the lungs, and the bladder. • Smooth muscle are under involuntary control
Skeletal Muscles • Skeletal muscles are attached to bone and cause body movements. • Almost all skeletal muscle is under voluntary control • Skeletal muscles work together, under going opposing actions to produce movement. One muscle contracts while the other muscle extends.
Structure of the Muscular System • A muscle is made up of hundreds of long cells called fibers. • Major muscles in the body are made up of hundreds of bundles of these fibers.
Skeletal Muscle Continued… • Muscles work together in opposing forces, when one muscle contracts another muscle relaxes. • The flexor is the muscle that closes a joint. • The extensor is the muscle that opens a joint.
Cardiac Muscle • Cardiac muscle is a type of striated muscle that forms the wall of the heart. • The involuntary cardiac muscles are responsible for the contraction of your heart.
Care of the Muscular System • Regular physical activity is the best way to keep your muscles strong and healthy. • Muscles that remain unused for long periods of time will atrophy, or decrease in size and strength.