Exploring Human Skeleton
Aseel Samaro
Human skeleton
There are 206 bones in the human skeleton.
which one is the smallest?
which one is the largest?
Each one contains calcium to make it strong.
Bones
make
up
the
human skeleton. Without
your skeleton you would flop!
The main bones
of the human skeleton 
Investigating the structure of the bone
 Bones must be strong to support you.
 Most of the bones (approximately 70 per cent) is made up of hard minerals, such as 
calcium.
 The outside of a bone is smooth and hard to provide support.
 Inside this hard outer layer lies spongy, porous material  This spongy layer allows your
bones to bend slightly.
 It also makes your bones lighter than if they were completely solid.
 At the centre of a bone is a softer substance called marrow.
Comparing bones
 Some bones are long and narrow, such as
those in your arms.
 Some bones are shorter, such as those in your
feet.
Femur
 Other bones are flat and wide, such as the
scapula (shoulder blade).
 Each bone is adapted to suit its function.
For example, the foot contains many small bones
to allow flexibility.
Scapula
Q.7 Page 11
For each of the examples below, describe how the bone shape or
structure is well adapted for its function in the body:
Femur (thigh bone) long and wide: gives strength to support the
body weight
Bones of the hand  Many small bones with joints: allows the hand
to bend in different directions
Ribs  curved: to protect lungs inside the chest cavity
What feature of bird’s bone help them to
fly ?
 The structure of bone in bird has perfectly adapted to the function of
flying
 Many bones in birds are hollow. They are full of air
 This makes them lighter and, therefore, less energy is needed for
them to fly
Analysing the skeleton
The human skeleton has four main roles:
Supports the body
Protects the organs
Allows movement
Produces blood cells.
 Without a skeleton you would not be able to sit, stand or hold
yourself up.
 The ribs are curved bones, forming a cavity inside the ribcage. The
lungs are positioned inside the ribcage.
 The many joints in your skeleton allow you to move. For example, the
joint at the knee allows your leg to bend. Without joints, your
skeleton would be rigid.
Did you know ?
 Your ears and the end of your nose do not contain bone. Instead,
these body parts are given their shape by cartilage.
 Cartilage is softer than bone and does not contain blood vessels or
nerve cells.
Bone
Explain which organ each part of the
skeleton protects:
Ribs
Cranium
Describe three parts of the skeleton where joints
are important.
The importance of bone marrow
 Bone marrow is in the centre of large bones.
 It is here where blood cells are made.
There are three types of blood cells :
Red blood cells  carrying oxygen
White blood cells
Platelets.
 Patients with some medical conditions cannot make their own healthy blood
cells.
 If a bone marrow transplant is carried out the patient may then make healthy
blood cells again.
What is meant by transplant?
Transplant: transferring living tissue from one person to
another
Using Bone Measurements
 Your skeleton has many symmetrical features.
 This helps you to balance and co-ordinate movements.
 Skeletons are usually made in similar proportions.
For example, if you stretch your arms as wide as you can and measure their arm
span, this will probably be similar to your height.
 At an archaeological dig or a crime scene, only a few bones may be found.
 Yet scientists can predict the height of a person using only the length of:
 The femur
 Humerus
 the smaller bones in the arms and legs.
The calculation used to estimate height from the length of the femur is:
 height (m) = (length of femur (m) × 2.6) + 65
 A femur, 0.35 m in length, is found during a police investigation.
Estimate the height of the victim. (Remember units). Estimate the
arm span of the same victim.
Using Bone Measurements
Calculation is not always accurate in people between 12
and 18 years of age. WHY ??
Thank you