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The Active Body

• The skeleton supports the body and allows movement.
• The names of some of the bones in a human skeleton.
• A joint allows movement of bones.
• Muscles provide the force needed to move bones.
• Muscles can only pull.
• When one muscle in a pair contracts the other relaxes. They are 'antagonistic'.
• Many bones work like levers.
• Cartilage and synovial fluid reduce friction at a joint.
• Tendons join muscles to bones. Ligaments join bones to other bones.
• Sports injuries often affect muscles and bones.
• A reflex is an automatic that is often protective.
• Sense organs detect changes around us.
• Muscles are controlled by messages that travel along nerves.
• Some sports need fast reaction times.
• Skin is sensitive to heat, cold, touch, pain and pressure.
• Skin sweats and looks flushed when it is hot and pale when it is cold.
• How blind people can read using Braille.
• How some clothes are designed to cut down heat loss.
• Kidneys control the amount of water in the body.
• Kidneys remove waste from the blood and produce urine.
• How a dialysis machine is used to treat patients with kidney problems.

In this topic we learn all about bones and joints, how to keep healthy, kidneys and the skeleton.

The skin is a barrier to the outside world against bacteria etc. The skin is also very sensitive to we can feel things The skin's main function is temperature control. Below is how the skin is able to change the bodies temperature

Cooling the body:
Blood capillaries widen (vasodilatation) to bring more blood near the surface of the skin so heat can be lost into the surroundings by radiation and convection. Sweat is produced which, as it evaporates, has a cooling effect on the body. Hairs lie flat which allows warm air to escape faster

Warming the body:
Blood capillaries in the skin become more narrow (vasoconstriction) so less heat is lost into the surroundings. Sweating decreases so less heat is lost. Hairs on body stand up on end to trap air which reduces warm air escaping so rapidly

Skeletons and Muscles

The skeleton of any animal has many functions including:

Protection:
The skull protects the brain and the rib cage protects the heart and lungs. The backbone is important to protect the spinal chord.

Support:
Bones give us shape and a framework for vital organs to be stored safely inside.

Blood formation:
In some bones there is red bone marrow which produces red blood cells.

Movement:
Muscles are attached to bones and bones have joints which allow the body to move. Animals need to move towards food and away from predators.

Skeleton muscles:
These muscles are attached to the skeleton. A muscle is attached to bones via a tendon. Muscles that work in pairs are known as antagonistic muscles. When muscles contract, they pull the bone to which they are attached closer. As one muscle contracts, the other relaxes. Muscles are effects which respond to nervous impulses.

Peristalsis is the movement of muscles to force food along the gut. This happens without our control.

There are two main types of joints (where two bones meet):
Hinge joints: Move in one direction like a hinge. Up and down. e.g. knee joint
Ball and socket joints: These can move in many directions freely. e.g. shoulder

You can feed any desire to see inside real animals and learn about the function of the internal organs. Safe in the knowledge that no scalpels or frogs will be used in the lesson, they can dissect a frog at http://homeworkhelp.about.com/teens/homeworkhelp/gi/dynamic/offsite.htm?site=http://www%2Ditg.lbl.gov/vfrog/dissect.html.
The 'Inner body' at http://www.innerbody.com/htm/body.html allows you to find out the size, weight, location and function of each human body organ.

Some sites that may help you are:-

These are super skeleton sites that name bones and show you all about them and joints.

http://www.gwc.maricopa.edu/class/bio201/muscle/mustut.htm

This site tells you all about muscles

What you should be able to do.

• Match the joints to their type of movement.
• Investigate how the length of a straw changes its strength.
• Find out which muscle contracts and which relaxes when the arm and leg move.
• Test your finger strength in an investigation.
• Make a model arm to show how the muscles work.
• Locate three levers found in the human skeleton.
• Carry out 4 trials of strength and find out which muscles are used.
• Investigate 4 reflexes and know why they are useful.
• Measure your reaction time with a falling ruler.
• Describe how the reacts to different water temperatures.
• Carry out an experiment to find out which parts of the hand and arm are the most sensitive to touch.
• Carry out an experiment to show that a small animal cools down more quickly than large animals.
• Interpret data on the effect of temperature on the amount of sweat and urine produced.
• Explain the differences in the amounts of chemicals in the blood and in the urine.