• A muscle is an elastic bundle of flesh under the skin that is attached to bones.
  • A muscle is a special elastic tissue that contracts and relaxes to produce movement.

There are two types of muscles.
i. Voluntary muscles.

ii. Involuntary muscles.

Voluntary muscles / skeletal muscles.

Voluntary muscles are muscles whose action is normally controlled by an individual’s will.

Examples of voluntary muscles include;

  1. Biceps (flexor)                                               ii.Triceps (extensor)

Involuntary muscles smooth muscles.

Involuntary muscles whose movement is not under our will.

Examples of involuntary muscles;

  1. Cardiac musclesof the heart.
  2. Muscles of the eye lids.
  3. Muscles of the stomach and intestines

Antagonistic muscles

These are muscles that work in pairs but have an opposite effect to each other.

Examples of antagonistic muscles include;

  1. Biceps (flexor)                                               ii.Triceps (extensor

Functions of the muscular skeletal system.

1. Protects the delicate body organs.

2. It provides supports to the body.

3. It helps in movement.

4. Storage of minerals like calcium and phosphorus.

5. The bone marrows are used to produce blood cells.

6. Provides room for attachmentof muscles.

Diseases and disorders of bones, muscles and the system

Disorders of the muscular skeletal system.

  • Fractures
  • Sprain
  • Spinabifida -The spinal cord does not form properly.
  •  Cuts
  •  Strains
  •  Dislocation

Diseases of the muscular skeletal system.

  • Rickets-causes bowed legs in children due to lack of Vitamin D.
  • Poliomyelitis– Cause by polio virus which attacks the nerve cells and spinal cord causing paralysis.
  • Arthritis-pain, stiffness and swelling of joints.
  • Scurvy– caused by lack of ascorbic acid (vitamin C) in the diet.

Prevention of diseases and disorders of bones, muscles.

  1. Boil water for drinking to prevent polio.
  2. Prepare and eat a balanced diet.
  3. Do physical exercises.
  4. Keep sharp cutting objects far from children’s reach.
  5. Go for dental checkups regularly.
  6. Put on shoes while walking.

Health habits that help to keep the system in a healthy working condition

  1.  Do daily physical exercises.
  2. Eat a balanced diet.
  3. Ensure proper body posture.
  4. Brush and floss your teeth twice a day.


  • It is a way a person positions his body when sitting, standing or walking

The correct sitting Posture.

  • Sit up straight on the chair.
  • Place both feet on the floor.
  • Put all your weight on both bottoms.
  • Do not tighten your ankles and knees.

Importance of correct posture

  1.  Prevents body aches.
  2.  It prevents one from growing bent bones.

Topical questions.

1.Which class of food is necessary for proper growth of bones?

2. Write down one example of each of the following

a) Skeletal muscles        b) Smooth muscles

3. What is the functional difference between ligaments and tendons?

4State one disorder to each of the following

  1. Ligaments     b) tendons.

5. Which part of the skeleton protects the following?

        a) Brain                b) tendons

6. State one health habit that can keep one’s skeleton in a healthy working condition.