What would happen if humans didn’t have bones? BONE FACTS

How many bones do humans have? When you are born you have over 300 Some fuse together as you grow As an adult you have 206 bones

How many bones are in the human hand? 27

How many bones are in your face? 14

What’s the longest bone in your body? Femur – about ¼ of your height

What’s the smallest bone in the body? Stirrup bone – found in the ear

How many bones do giraffes have in their neck? 7 – same as humans (only theirs are much much larger)

EFFECT OF FITNESS ON BONE When bones are subjected to regular physical activity and habitual loads, they tend to become denser and more mineralized E.g. Right forearm of the right-handed tennis players is more dense than her left one from using it more frequently Inactivity works in the opposite direction, leading to a decrease in weight and strength E.g. loss of bone mass has been noted in bed-ridden patients, inactive senior citizens and astronauts

THE HUMAN SKELETON *

FUNCTION OF THE SKELETAL SYSTEM - to provide the supporting framework - to protect the body organs Bone is a living tissue complete with blood supply and nerves

Bone is composed of: Collagen (a protein): Calcium carbonate & calcium phosphate: Collagen (a protein): Makes up 60 – 70 % of bone weight Provides much of the bone’s stiffness and resistance to pressing or squeezing forces Water: Consists of much smaller proportion of water than other body parts Gives bone it’s characteristic flexibility and contributes to it’s ability to resist pulling and stretching forces With aging, collagen is lost progressively and bone becomes more brittle

WORKSHEET: ANATOMY OF A LONG BONE Use your text book to complete the worksheet.

BONE SHAPE The shapes of the bones allow them to perform specific functions more effectively

SHORT BONES Include bones of ankle (ie. tarsals) and wrist (ie. carpals) Serve as good shock absorbers

LONG BONES Include femur of the thigh, humerus of the upper arm and others Any bone whose length greatly exceeds its diameter Provide levers for movement

FLAT BONES Include bones of the skull, scapula, ribs, sternum and clavicle Largely protect underlying organs

IRREGULAR BONES Include bones of your face and vertebrae Bones that cannot be placed in other groups Fulfil special functions

SESAMOID BONES Oval like a pea and found in tendons Include the patella

WORKSHEET