The Skeletal, Muscular, and Nervous Systems Body Systems The Skeletal, Muscular, and Nervous Systems

The Skeletal System Consists of 206 bones and the attached connective tissues The connective tissues cushion bones, attach bone to bone, and attach bone to muscle Functions of the skeletal system include Providing support for the body Protecting internal tissues and organs from damage Acting as a framework for attached muscles Allowing movement for limbs and fingers Producing new red and white blood cells Storing fat and minerals, such as calcium and phosphorus

Bones, Connective Tissue, and Joints Bones - made up of living tissues formed into layers Outer layer is hard, densely packed, compact bone Beneath that is spongy bone, a less dense bone with cavities filled with red bone marrow; where blood cells are produced Some bones contain yellow marrow, connective tissue that stores fat Connective tissue - three types include cartilage, ligaments, and tendons Cartilage is a strong, flexible connective tissue that acts as a cushion between bones to reduce friction Also acts as a flexible structure for soft parts of the body All bones begin as cartilage and harden into bone during ossification

Bones, Connective Tissue, and Joints Connective tissue - three types include cartilage, ligaments, and tendons Ligaments are bands of fibrous, slightly elastic connective tissue that attaches bone to bone Ligaments attach to bones to create joints A tendon is a fibrous cord that attaches muscle to bone

Caring for the Skeletal System Your overall health depends on the health of the skeletal system. Foods high in calcium, vitamin D, and phosphorus help prevent skeletal disorders During regular check-ups, your doctor can screen you for skeletal disorders Scoliosis - a lateral or side-to-side curvature of the spine Fracture - any type of break in a bone Compound fracture - broken end of the bone breaks through the skin Simple fracture - broken bone does not break through the skin

Skeletal System Injuries Fractures Hairline - parts of the bone do not separate Transverse - the fracture is completely across the bone Comminuted - bones shatters into more than two pieces

Injuries to Joints Dislocation - when a bone slips out of place, tearing the ligaments Torn cartilage - sharp blow to a joint or severe twisting of a joint Bursitis - painful inflammation of bursa, a fluid-filled sac that helps reduce friction Bunions - painful swellings of the bursae in the first joints of the big toe Arthritis - inflammation of a joint resulting from an injury, natural wear and tear, or autoimmune disease

The Muscular System Muscles are elastic, stretching to allow a wide range of motion Some muscles in the body are always at work Help you breathe Make your heart beat Move food through the digestive system A muscle is made up of hundreds of long cells called fibers Fibers are stimulated by nerve impulses Contract, or shorten, and extend, or stretch

Types of Muscles Smooth muscles - act on the lining of the body’s passageways and hollow internal organs Found in: Digestive tract urinary bladder Lining of blood vessels Passageways that lead to the lungs Smooth muscles are involuntary muscles

Types of Muscles Skeletal muscles - attached to bone that cause body movements Look striated, or striped, under a microscope Most muscle tissue falls under this category Most skeletal muscles are voluntary

Types of Muscles Muscle pairs work opposite of one another to perform a task Flexor - muscle that closes a joint Extensor - muscle that opens a joint

Types of Muscles Cardiac muscle - striated (striped) muscle that forms the wall of the heart Involuntary Responsible for the contraction of your heart

Caring for Muscles Get regular exercise Eat high protein foods to build and repair muscle tissue Practice good posture to strengthen back muscles Use proper equipment and wear appropriate clothing to protect muscles during any physical activity Warm up properly and stretch before exercising; cool down after exercising to prevent an injury

Understanding Muscular Problems Bruises - areas of discolored skin that appear after an injury, causing blood vessels beneath the skin to rupture Strains and sprains - result when muscles are stretched or partially torn from overexertion Tendinitis - inflammation of a tendon due to injury, overuse, or natural aging Hernia - organ or tissue protrudes through an area of weak muscle Muscular dystrophy - fibers are progressively distroyed