3. Bones* of 29
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KS4 Physical
The functions of the skeleton
The way bones affect body shape and size and their effect upon weight and performance
How bones provide support, movement and protection
To recognise and name bones
The 5 regions of the vertebral column
To classify different types of bones.
What we will learn in this presentation:
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Ossification
Ossification is the process by which bone is formed from cartilage. The cartilage cells die off and are calcified to produce bone.
As a baby grows the cartilage becomes bone and hardens. This is part of the process of bone growth.
In the womb the skeleton of the foetus is initially formed from an elastic tissue called cartilage (except for the clavicle and parts of the cranium).
The cartilage skeleton of a foetus is sometimes known as a ‘temporary skeleton’.
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Bone growth
Note: the process of bone growth at the growth plate involves simultaneous growth of cartilage and ossification in the shaft. The processes appear to occur alternately within the animation, in order to make the process more clear.
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epiphysis
epiphysis
diaphysis
The end (or head) of the bone is called the epiphysis.
It is made up mainly of spongy bone which is full of tiny cavities.
The shaft of the bone is called the diaphysis. It is hollow and made up of hard, dense compact bone.
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Diet and exercise for healthy bones
Certain substances are needed for this process of growth and renewal. These need to be include in your diet.
Minerals are important. They are inorganic substances which perform a variety of functions in the body.
Calcium is the most important for bone strength. It is found in cereals, milk and other dairy products. Some fish and vegetables also contain calcium.
Bones are alive. Old cells and bone tissue are constantly being broken down and replaced by new ones.
Osteoblasts - are bone cells that make new bone.
Osteoclasts – are bone cells that break bone down.
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Diet and exercise for healthy bones
As well as a good diet, regular weight-bearing exercise can help to maintain bone density and strength.
Weight-bearing exercise can include walking, jogging and ball or racket games.
After the age of 35, bone tissue begins to be broken down
more quickly than it is replaced.
This means that bone density and strength begin to deteriorate. Osteoporosis can occur, where bones become very brittle.
Swimming does not help, as your weight is supported.
Exercising makes osteoblasts work harder and will therefore keep bones strong, even though as we age osteoblasts don’t work as hard. That’s why it is important to keep doing weight bearing exercises as we get older.
Losing too much bone density and strength can result in osteoporosis.
Image © 2006 Jupiterimages Corporation
The skeleton performs many functions in the body.
Shape – The skeleton gives us our shape and determines our size.
Blood cell production – blood cells are made in the bone marrow.
Movement – The skeleton allows us to move. Muscles are attached to the bones and move them as levers.
Protection – The skeleton protects delicate parts of the body like the brain and lungs.
Support – The skeleton supports muscles and organs.
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Your skeleton affects your body shape and size.
Bones play an important part in determining your height and build. People with long, light bones are usually tall and thin, whilst people with short, thick bones are likely to be short and more heavily built.
Some sports are more suited to people of a particular size or body shape. This means that your skeleton and bone size can affect your performance in different sports.
For example, weightlifting
favours individuals with
strong, heavy bones.
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The skeleton acts as a framework.
It gives the body support, enabling us to stand and walk upright.
The bones of the back and chest support internal organs and help to keep them in place.
The bones of the body are held together by ligaments.
The skeleton provides a framework for the muscles, which are attached to bones by tendons.
Can you imagine what humans would look like if they didn’t have bones to support them?
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Bones work with muscles to produce movement.
Muscles are attached to bones by tendons.
Bones have surfaces that allow for strong attachment. Tendons fuse with the tough Periosteum membrane on the outside of the bone.
Muscle
Tendon
Periosteum
Bone
Protection
Some of our body parts, such as the brain, are very delicate and need protection from external forces.
Bones can protect body parts from impacts and injuries.
The cranium protects the brain.
It encloses the brain entirely in a shell of bone.
The rib cage protects the delicate organs of the chest.
Can you think of two reasons why the rib cage has gaps in it rather than being a solid shell of bone?
cranium
Answers:
The rib cage needs to be flexible enough to allow the movements necessary for breathing.
A solid bone rib cage would be extremely heavy, making movement more difficult.
Could also point out that the organs of the chest are not quite as delicate as the brain, so solid bone protection is less necessary.
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Blood cell production
Red and white blood cells and platelets are made in the bones.
The ends of long bones and some other bones including the ribs, humerus, femur and even vertebrae bones, contain red bone marrow.
This is where the blood cells are produced.
The shaft of long bones is filled with yellow bone marrow which does not produce blood cells.
Red marrow embedded in spongy bone
Yellow bone marrow in the shaft
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Clavicle (collar bone)
Encourage students to learn both the common name and scientific name of each bone.
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Carpals
Metacarpals
Phalanges
Tarsals
Metatarsals
FOOT
HAND
Encourage students to learn both the common name and scientific name of each bone.
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The spine is also known as the vertebral column.
It is made up of 33 irregularly shaped bones called vertebrae. Between each vertebra there is a pad of cartilage which allows movement and prevents the bones grinding together.
The vertebrae protect the spinal cord. This important nerve runs up the spine, through the centre of each vertebra.
The vertebral column is
divided into 5 sections.
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Classification of bones – long bones
Bones are divided into a number of different categories. So far we have mainly dealt with long bones.
Long bones have a long shaft containing yellow bone marrow.
They are responsible for a lot of movement and often act as levers.
Long bones include the femur, humerus, tibia, fibula, the metatarsals, metacarpals and phalanges.
Long bones contain red bone marrow for producing blood cells.
Long bone
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Flat bones perform a variety of functions. These include:
They are made up of spongy bone between two layers of hard compact bone.
They have a large surface area.
protection for delicate areas, for example, the cranium protects the brain.
areas for muscle attachment, for example, many of the muscles of the lower back and legs attach to the wide flat bone of the pelvis.
Cranium
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Short bones are very light and very strong.
They are small and squat in shape.
They are composed of spongy bone with a thin layer of compact bone on the outside.
The carpals in the wrist and the tarsals in the foot are examples of short bones.
carpals
tarsals
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Irregular bones are specially shaped to perform a particular function.
They are composed of spongy bone on the inside and compact bone on the outside.
Examples include the patella and the vertebrae.
The patella is shaped so that the quadriceps tendon slides easily over the knee joint.
patella
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Name the process by which bone is formed from cartilage.
Bones perform a number of functions in the body.
Name two functions of the skeleton.
Give an example of a bone which performs each of the functions you listed above.
3. Karim wants to become a professional basketball player.
How may Karim’s skeleton affect his performance?
Suggest two things that Karim could do to make sure that his bones stay healthy as he gets older.
Ossification
a) Possible functions: shape, movement, support, protection, blood production.
b) Shape – e.g. clavicle gives shape to the shoulder (almost any bone can be used here).
Movement – e.g. femur allows movement of the leg.
Support – e.g. the ribcage supports internal organs.
Protection – e.g. the cranium protects the brain.
Blood production – e.g. blood cells are made in the red bone marrow in the humerus (or any other long bone).
a) The skeleton determines many physical attributes, especially height and build. Basketball favours tall performers with light bones. Performers in high
intensity sports like basketball require strong bones.
b) karim could eat a healthy balanced diet rich in minerals like calcium. He could also make sure that he does regular weight-bearing exercise.
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Ossification
Cartilage
Epiphysis
Diaphysis
Periosteum