M USCULOSKELETAL S YSTEM Bones & Muscles

THE SKELETAL SYSTEM All of the bones in the body and the tissues (tendons, ligament, and cartilage) that connect them. Skeleton: job Provide support/shape Enables you to move Protects your organs Produces blood cells Stores minerals and other materials 206 BONES IN YOUR BODY At birth, you have about 300 bones

THE SKELETON

B ONES A RE ALIVE!! Bones are alive in the body Have nerves, blood vessels, cells and tissues

W HAT IS BONE MADE OF ? Compact Bone (outer layer)  hard or compact bone Spongy bone  inside (holes) lighter and slightly flexible Marrow  jelly-like bone Middle (produce new blood cells)

J OINTS Joint  the place where 2 bones meet There are 3 kinds of joints: Fixed  prevent movement, found in the skull Semi-movable  permit limited movement, vertebral column Moveable  wide range of movement  hinge  ball and socket  saddle -  gliding joint – intercarpal  pivot

H INGE J OINT Forward and backward motion Elbow and knee

B ALL & S OCKET JOINT Broad range of motion Shoulder and hips

P IVOT JOINT One bone rotates around another neck

G LIDING J OINT Allows one bone to slide over another Wrist and ankle

B ONE / MUSCLE ( CONNECTIVE ) TISSUES Cartilage  Firm tissue at the ends of the joints (nose/ears) Ligaments – connect bones to one joints, elastic (connective tissue) Tendons – connect muscles and bones, tough/non-elastic (contract muscle) _______________________________________ Synovial fluid  fluid that protects the ends of bones

OSTEOPOROSIS Condition in which the bones become weak and break easily As you age, bones lose some minerals

MUSCLES Make up the bulk of the body and 1/3 of its weight Provides movement and force 3 types of muscle Made up of muscle fibers Works in opposable pairs (one contracts, the other relaxes)

3 TYPES OF MUSCLE 1. Skeletal – attached to your bones and provides the force to move your bones, striated (voluntary) 2. Smooth – inside many internal organs (stomach)  involuntary, move slowly 3. Cardiac  found only in your heart  involuntary and striated, does not get tired

V OLUNTARY VS. I NVOLUNTARY M USCLE Voluntary  Under your conscious control  skeletal muscle Involuntary  not under your conscious control (breathing) smooth and cardiac

M USCLE C ONTRACTION  An all or none response – they contract or remain relaxed

N ERVES Threadlike, carry impulses that stimulate the muscles to contract