This unit talks about muscular and skeletal system of the human body.It shows different parts of the skeleton and parts of muscles.

Definition of the skeleton.

  • A skeleton is a frame work of bones in the body.

    The structure of the human skeleton

Types of skeletonsImage result for skeleton

They include;

  • Hydrostatic skeleton
  • Exo skeleton
  • Endo skeleton

Hydrostatic skeleton.

  • This is a type of skeleton where the body of an organism is filled with a liquid under pressure.
  • Organisms with hydrostatic skeleton include;
  • Earth worms.

Exo skeleton.

  • This is a type of skeleton found outside the body of a creature.
  • Exo skeleton is common with insects and crustaceans e.g. house flies, grass hoppers, mosquitoes e.t.c
  • Exo skeleton provides support and protection to soft parts of an insect.

Endo skeleton.

  • This is a type of skeleton found inside the body of an organism.
  • Organisms with endo skeleton include, man( human beings) cows, goats e.t.c
  • Endo skeleton is made of bones and cartilages.



  • Bones are hardest tissues found in animals with back bones (vertebrates).
  • Bones contain living cells which are supplied with food and oxygen by blood vessels.
  • Bones are made from mineral salts and proteins.
  • Mineral salts include calcium and phosphorus.

Below is a virtual tour to take you through the Types of bones in the human body. You can rotate the image up to 360 degrees to see everything around it. The arrow button takes you to the next bone type, other buttons contain information and assignment on the type of bone displayed. You can also listen to the audio using the voice button below each image.


Definition of a joint:

  • A joint is where two or more bones meet in the body.

Types of joints

These include: – Movable joints

– immovable joints

Movable joints                                                                                                                                                                                         Illustration of a movable jointImage result for Movable joints

  • These are joints which allow movement.
  • Movable joints are held together by ligaments and tendons.

Examples of movable joints

  • Hinge joint.
  • Ball and socket joint.
  • Pivot joints.
  • Gliding / plane joints.

Hinge joint

Illustration of a hinge joint

Image result for Hinge joint

This is a type of movable joint which allows movement in one plane.

Examples of hinge joint

  • The elbow joint.
  • The knee joint.

NB: They are called hinge joints because their movement is like that of a door on its hinges.

Illustration of the structure of hinge joints.

Illustration of the structure of hinge joints.




Ball and socket joints


  • This is a type of movable joints which allow movement in three planes or all directions. i.e. forward, backward, side ways and in circular form.


  • The shoulder joint.
  • The pelvic girdle (hip joint)

They are called ball and socket because the ball shaped end of one bone fits into a socket in the other bone.

Illustration of the structure of ball and socket joint.

ball and socket joint
The ball and socket joint

Pivot joints

  • This is a type of joint which allows rotation of certain parts of the body on other parts.
  • An example of pivot joints is the neck vertebra.
  • Pivot joints helps us to nod our heads.

Gliding joints

  • This is a type of joint where two moving bones are flat and slide over one another easily.
  • Gliding joints are found in the wrist and ankles.

Illustration of the structure of gliding joints.

 gliding joints
Gliding joints

Importance of joints.

  • Joints allow movements in the body.

Features of a typical movable joint

  1. The cartilage and synovial fluid – reduce friction in the joint.
  2. Ligaments – structures which join bones together at a joint.
  3. Tendons – structures which join muscle to bone.
  4. Synovial membrane – is a capsule of fibrous material whose inner membrane secretes synovial fluid.

Immovable joints

  • This is a type of joint that does not allow any movement because they are tightly fixed together.


  • The suture joints found in the skull.

An illustration to show the structure of the suture joints of the skull.


  • A muscle is an elastic substance found in the body of animals.
  • Muscles are connected to the bones by tough fibrous tissues
  • Muscles only relax and contract. They do not expand or elongate.
  • There are three types of muscles namely;
  • Voluntary or skeletal muscles
  • Involuntary or smooth muscles.
  • Cardiac muscles.
  • These are muscles whose movement can be controlled.
  • They are always attached to the skeleton.

Examples of voluntary muscles:

  • The biceps muscles of the hand which connects the scapula to the radius.
  • The Triceps muscle of the hand which connects the scapula, the humerus and ulna.

Diagram showing the arm and its parts.

  • When the arm is straight.
  • When the arm is bent.
  • These are muscles whose movement is automatic.
  • We have little or no control over them.

Examples of the involuntary muscles:

  • Muscles of the walls of the alimentary canal.
  • Muscles of the reproductive system.
  • Muscles of the blood vessels.
  • Muscles of the excretory system.
  • These are muscles whose movement is made by the muscles themselves.
  • We do not have any control over these muscles.

Examples of cardiac muscles.

  • Muscles of the heart;
  • These have the capacity to contract and relax throughout life without getting tired.
  • They only stop when the person is dead.


  • They help in joining bones in our body.
  • They help in movement (Locomotion).
  • They help animals to perform heavy duties.


  • Antagonistic muscles are muscles which work in pairs.
  • When one relaxes the other contracts.
  • Examples are the Biceps and Triceps muscles of the arm.


  • Posture means the position of the body for everything we do.
  • There is correct posture for sitting, standing, walking, running and sleeping.


  • We look smart.
  • Muscles of the abdomen and diaphragm become strong.
  • Good posture keeps the organs of the intestines in proper position.
  • Good posture helps the skeleton to develop in the right way.
  • Bad posture leads to indigestion and deformities of the skeleton.

Diagrams showing good posture for sitting, standing, walking, lifting.


Image result for good sitting posture  standing

Image result for good standing posture walking

Image result for good walking  posture lifting

Image result for good  lifting posture



  • It is caused by a virus passed out by an infected person in faeces.
  • The virus can get into our bodies through drinking contaminated water.
  • The virus can also get into our bodies by eating contaminated food.
  • The disease affects bones especially the limbs. That is why it is called the disease of the limbs or bones.

Signs and symptoms.

  • Paralysis or weakness in one or more bones.
  • Fever

Prevention and control of polio

  • Immunisation with polio vaccine by giving drops in the mouth.
  • Use latrines wherever possible.
  • Wash hands with soap and water before eating food.
  • Drink boiled water.


  • Tuberculosis is caused by a bacterium called a mycobacterium.
  • The bacterium was first discovered by Robert Koch in 1882.
  • The bacteria is spread through air.
  • There are several types of mycobacterium.
  • There is one which causes Tuberculosis of the lungs and the other which cause Tuberculosis of the spine o

Symptoms of tuberculosis of bones.

  • Long lasting painful backache.
  • A lump grows on the spine.
  • Pain in the backbone while walking.
  • Paralysis of the legs and failure to walk.

Prevention and control of tuberculosis.

  • Immunisation with BCG vaccine on the right upper arm at birth.
  • Isolate the infected person.
  • Treatment of the infected person.
  • Drink boiled or pasteurized milk because the bacteria also attacks cows and can be spread through un boiled milk.


  • It is caused by a bacterium found in the soil.
  • The bacteria enter the body through fresh cuts or wounds.
  • It attacks muscles making them stiff and also breathing becomes difficult.
  • In new born babies, it can enter through the umbilical cord if its cut with a dirty un-sterilised instrument like a razor blade or knife.

Signs and symptoms of tetanus.

  • Stiff muscles all over the body.
  • Spasms when touched.
  • The baby stops sucking mother’s breasts.

Prevention and control of tetanus.

  • Early immunization with DPT vaccine on the left upper thigh.
  • Treatment of the infected people

Dis-orders of the skeletal and muscular system.




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