Site author Richard Steane
The BioTopics website gives access to interactive resource material, developed to support the learning and teaching of Biology at a variety of levels.
Give 3 general functions for our skeleton.
> muscle attachment for movement
What is the name of the main classification group which includes fishes, amphibians, reptiles, birds and mammals but not other animals?
The central part of the skeleton is sometimes called the backbone or spine, but it is actually composed of a number of bones.
What is one of these bones called?
What is between these bones?
> (intervertebral) discs - pads of cartilage
What is the function of the hole nearly in the centre of each of these bones?
> allows spinal cord to pass through
Other groups of animals may have different types of skeleton, or none at all.
What are these types called? Give an example of each.
> exoskeletons e.g.> arthropods (insects, crustaceans, etc)
> liquid skeletons e.g.> earthworms, caterpillars etc
no skeleton e.g.> jellyfish, Amoeba etc
It is often said that, in evolution, animals faced problems in moving from an aquatic (water) to terrestrial (land) environment.
What is the main problem posed by this change in environment?
> apparent mass increased due to lack of buoyancy from water
In what ways does ANY sort of skeleton help an animal on land?
> support >protection >muscle attachment
What type of joint is involved at E and F?
E> ball and socket
What does a muscle do when it is working?
Which muscle (G or H) is involved in bending the arm?
What is the other muscle doing at the same time?
Why are G and H called voluntary muscles?
> under control of the will (brain)
Why are 2 muscles needed in this example (and in most similar situations in the body) ?
> one to perform action, one to undo it
What is the difference between a tendon and a ligament?
> tendon joins muscle to bone, ligaments join bone to bone
What is the function of the following parts of a joint, such as might be found at the elbow?
cartilage > cushions joint - slippery surface
synovial fluid > oily - acts as lubricant to help joint move smoothly
synovial membrane > secretes and retains synovial fluid
ligaments > holds bones together
Think of some reasons why some people's joints may not move so freely:
> damage to cartilage at articulating surface
> problems with synovial fluid or capsule
What materials are likely to be used in the construction of an artificial replacement joint, e.g. elbow, hip or knee?
For each part, give reasons for choosing that material.
> titanium/stainless steel? > strong, light, not likely to be rejected
> nylon/polypropylene? > slippery surface, absorbs shock
> acrylic cement > to hold inserts in position
Working in pairs, using rulers and a protractor, try to work out the following parameters which might be necessary for a successful knee joint replacement:
Angle through which leg bends when walking (steps of average size)
Angle through which leg bends when running (steps of average size)
Angle through which leg bends when going up stairs (average size)
Angle through which leg bends when going down stairs (average size)
Angle through which leg bends when sitting down (average size chair)
Angle through which leg bends when sitting down in deck chair
Angle through which leg bends when cycling (average size bike) - top
Angle through which leg bends when cycling (average size bike) - bottom
Angle through which leg bends when getting into car (average size)