Download Muscles and Bones PPT

Physical Health: Skeletal
and Muscular Systems
The Skeletal System
 Skeletal System – bones of the body, shields
important organs, gives your body shape
 Skull protects the brain / Ribs Protect your
heart and lungs / Back bone protects your
spinal cord
 Approx. 206 bones in the skeletal system
 Composed of nonliving mineral matter,
mostly calcium, and living tissue with blood
vessels and nerves
Structure of Bones
 Before you are born, skeleton appears as cartilage: tough supportive tissue,
similar to bone but softer and more flexible
 Bones grow and go through a process called ossification until you reach 2025 years old
 Ossification: calcium and phosphorus are deposited within most of the
cartilage in your body and changes them to bone
 With age, bones become thinner and do not absorb needed calcium
minerals. This process is called osteoporosis
 Osteoporosis and low bone mass represent 55 percent of the people aged
50 and older in the United States
Structure of Bones
 All bones are covered with a tough membrane called periosteum
 Periosteum: contain bone-forming cells that produce new bone for growth and repair
 Blood vessels run through, branch into the bone, and nourish the cells of the bone
 Beneath periosteum is a strong outer layer of compact bone. The inner layer is spongy
bone composed of hallow spaces which act as shock absorbers
 Bone Marrow: fills the spaces inside the hollow spaces within the spongy bone
 Two types – Red Morrow: found in the ends of bones, produces red blood cells and
white blood cells
- Yellow Morrow: found in the body of bones, composed mostly of fat cells
Structure of Bones
 Breaking down the human
skeleton
Two Sections
Axial Skeleton: Skull,
vertebrae, sacrum, ribs,
sternum
Appendicular Skeleton:
Bones of the arms, legs,
shoulders, and hips
Joints
 Joint: point at which two bones come together.
 Joints tightly fitted together are considered immovable.
Joints which allow the bones to bend, twist, or turn are
known as moveable joints.
 Four types:
 Ball and Socket: allows movement in all directions
(shoulders/hips)
 Hinge: permit bones to move back and forth (fingers, knees,
elbows)
 Gliding: allows bones to slide over one another.
 Ligaments: prevent bones from popping apart at these
joints. Connect bone to bone (MCL/ACL in the knee)
 Synovial Fluid: secreted in membranes around the joint
reducing wear on the bones (imagine oil for your car
engine as an example)
Muscular System
 Without muscles, you would not be able to walk breath, digest your food, or
swallow. Your muscular system even helps you produce heat.
 Three types – Skeletal, Smooth, and Cardiac
 Skeletal: Voluntary muscle. You control its movement.
 Skeletal muscle is connected by think strands of connective tissue called Tendons
 Smooth: Involuntary muscle. Works automatically to control movements inside
your body. Examples: breathing, digestion, and blood circulation
 Smooth muscle makes up the walls of your stomach, intestines, and blood vessels
 Cardiac: Involuntary muscle. Only found in the walls of your heart and is the
strongest muscle in your body
Muscular System
 All muscle (skeletal, smooth, cardiac) causes movement by contracting, or
becoming shorter and thicker
 Muscle contraction starts from the nervous system, travel along nerve cells
attached to your muscles
 When a muscle receives a message from a nerve, the muscle contracts.
When the message stops, the muscle relaxes, or lengthens
 Skeletal muscles work in pairs, one contracts as the other relaxes
 Example in the picture
Disorders of Skeletal and Muscular System
 Problems arise through consistent use. Most issues are caused by pushing
systems beyond their endurance or not properly prepared for an activity
 Fracture: break in a bone. Bone cracked or broken in two pieces.
 Closed Fracture: bone does not break through the skin
 Open Fracture: bone end breaks through surface of the skin
 Scoliosis: Curvature of the spine. Spine develops an abnormal curvature
to one side. Can be inherited or developed during child hood.
 Dislocated joints, ligaments around a joint stretched or torn.
 Muscle strains: overstretched or torn ligaments. Occurs when muscles
are over worked or stretched too far or too quickly.
 Muscle Imbalances (ex. Shin splints): calf muscles pulling the front of the
foot down overpower the shin muscles that pull the front foot up.
Keeping Muscles and Bones Healthy
 While your bones and muscles are still
forming, include calcium in your diet every
day
 Calcium requires Vitamin D to absorb into
bones (Vit.D – milk, bread, cereals, grains)
 Exercise keeps muscles toned and flexible.
Does not increase the number of muscle
fibers you have, helps make individual
muscle fibers grow
 In turn causes entire muscle to become
larger and thicker
 To prevent injury always warm up before
exercising to increase blood supply to your
muscles. Cool down afterwards to prevent
muscle injuries.