Notes on Skeletal System | Grade 7 > Health and Physical Education > The Human Body | KULLABS.COM

Skeletal System

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Introduction

As we know human body work like a machine. All the human organs are made of a structural and functional part is called cells. A tissue means a combination of similar characteristics, cells, having similar functions, and features. It also grows organs and different organs have a different function which is carried out by the human body. For example, ears catch the sound where as the eyes gives us vision. To form a system many organs act together.In our body, we have altogether nine systems.Some of them are a skeletal system, respiratory system, digestive system, muscular system etc. These systems are coordinate itself by our body. Our brain controlled, agree and regulated all the system of our body. As a whole, our body is made of these nine systems.

Skeletal System

www.britannica.com
www.britannica.com

The skeletal system is that system which is composed of different sizes and shapes of bones. The skeleton gives a certain shape and holds the different organs in a fixed position to form the body. The human body is made of millions of microscopic cells. Muscles are made of cells and tissues. Here, a body has different types of bones like flat, long, short and irregular bones. A human skeleton is consist of 206 pieces of bones. Those bones are joined to muscles with the help of ligaments and tendons. These joined bones help to move in different directions for their smooth functioning.

Function of bones :

In human body, the skeletal system performs the following function;

Source:gemn.dvrlists.com Fig; Human bones
Source:gemn.dvrlists.com
Fig; Human bones
  • The major functions of the bone are to provide a skeleton and shape to the body Because of bones we are able to stand.
  • In the movement of body bones and muscles plays an important role. Due to this joined bones help to move in different directions for their smooth functioning.
  • The bones protect the inner vital organs like; heart, spinal cord, brain, lungs etc whereas lungs and heart are protected by ribs, the spinal cord is protected by the backbone and skull protects our brain.
  • The bone marrow in the long bones helps in the production of red blood cells (RBCs). It helps to transport oxygen.
  • Some minerals like phosphorus and calcium are stored in bones.

Types of bone on the basis of size :

Flat

Such bones protect the internal organs of our body and they are flat in structure. It provides a skeleton and gives shape to the body. Scapula (at the shoulders), Skull (at the head) and Sternum and ribs (at the chest) are some example of flat bones.

Long Bones

In our body, there are limited long bones. The hands and legs are located as long bones.Radius and Ulna (at lower arm),Humerus(at upper arm) Femur (at thigh) and Tibia and Fibula (at lower leg) are some long bones of our body.

Short Bones

We know that human has 206 bones in our body. It also has many short bones in our body which are located different parts of the body. Some example of short bones is Carpals (at twist),Metacarpals (at palm) and Phalanges(at fingers).

Irregular Bones

The internal organs protect the irregular bones. Such bones do not have definite shape or size. These bones are attached together by immovable joints. Vertebral column (at back) and facial bones are the examples of irregular bones.

Joints

The place where two or more than two bones are connected with each other to form a junction is called joints. Here, bones are attached to each other with the help of ligaments.It helps to join two or more bones and moved for their smooth functioning. In human body, there are three kinds of joints they are:

Source:www.interactive-biology.com Fig:
Source:www.interactivebiology.com Fig:Joints
  1. Immovable joints
  2. Semi-Movable joints
  3. Movable joints

Immovable joints

Those joints which do not move at all is known as immovable joints.Its joints of the cranium are immovable joints. The ligaments don't allow movements of joints because it is tight and fixed.

Semi-movable joints

The joints which can be moved partially is known as semi-movable joints. With the help of cartilage, bones are able to move slightly. Ribs and Column are the examples of semi-movable joints.

Movable joints

Source:www.physio-web.org Fig;
Source:www.physio-web.org Fig;Movablejoints

The joint which allows free movements in fixed path depending on the type of joints is known as movable joints.It is also called synovial joints as they contain synovial liquid in the membrane. There are five types of movable joints.Such types of movable joints are :

  1. Hinge Joint
  2. Saddle Joint
  3. Gliding Joint
  4. Pivot Joint
  5. Ball and Socket joint

Hinge Joint:The joint in which the bones can move to and for like a door which opens only one way is known as a hinge joint. Elbo, ankle, knee etc are the hinge joints.It also prevents the movement in opposite direction.

Saddle Joint: The joint whose one piece of bone can slide with the other bone resting on it . Such joints which found the bones of palms and feet.

Gliding Joint:The joints which move above each other by gliding or sliding is known as gliding joint. The example of gliding joints is the wrist and ankle. Gliding joints are flexible to stretch, move and compress.

Pivot Joint:The joint which is formed in such a way whose one bone rests on the other and the first moves freely around the other. The skull rotating around the upper end of the vertebral column is the best example of the pivot joint. Radius and Ulna are the examples of pivot joint.

Ball and socket joint: A joint is formed from two bones where an end part of a bone is in the shape of a ball and the hollow of another bone is called ball and socket joint. The bone which end is like a ball is fit inside the socket of the another bone it freely moves around in 360o. The example of ball and socket joints are joint between the upper arm bone with shoulder bone and upper leg bone(femur) with pelvic bone at hips.

Source:www.daviddarling.info Fig:
Source:www.daviddarling.info Fig:Ball and socket joint



 

  • The skeletal system is that system which is composed of different sizes and shapes of bones.
  • The place where two or more than two bones are connected with each other to form a junction is called joints.
  • Those joints which do not move at all is known as immovable joints.Its joints of the cranium are immovable joints.
  • The joints which can be moved partially is known as semi-movable joints. 
  • The joint which allows free movements in fixed path depending on the type of joints is known as movable joints.It is also called synovial joints as they contain synovial liquid in the membrane.
.

Very Short Questions

The four function of bones is given below :

  • The bones protect the inner vital organs like; heart, spinal cord, brain, lungs etc whereas lungs and heart are protected by ribs, the spinal cord is protected by the backbone and skull protects our brain.
  • The bone marrow in the long bones helps in the production of red blood cells (RBCs). It helps to transport oxygen.
  • The major functions of the bone are to provide a skeleton and shape to the body Because of bones we are able to stand.
  • In the movement of body bones and muscles plays an important role. Due to this joined bones help to move in different directions for their smooth functioning.

The types on the basis of bone are:

Long Bones- In our body, there are limited long bones. The hands and legs are located as long bones.

Short Bones-We knows that human has 206 bones in our body. It also has many short bones in our body which are located different parts of the body.

Flat-Such bones protect the internal organs of our body and they are flat in structure. It provides a skeleton and gives shape to the body.

Irregular Bones-The internal organs protect the irregular bones. Such bones do not have definite shape or size. These bones are attached together by immovable joints.

 

             

 

 

The joint which allows free movements in fixed path depending on the type of joints is known as movable joints.It is also called synovial joints as they contain synovial liquid in the membrane. There are five types of movable joints.Such types of movable joints are :

  1. Hinge Joint
  2. Saddle Joint
  3. Gliding Joint
  4. Pivot Joint
  5. Ball and Socket joint

0%
  • All the human organs are made of a structural and functional part is called ________ .

    organism
    germ
    spore
    cells
  • Our brain _______, agree and regulated all the system of our body.

    repress
    check
    command
    controlled
  • The skeletal ______ is that system which is composed of different sizes and shapes of bones.

    method
    way
    order
    system
  • The human body is ,made of millions of microscopic cells.Muscles are made of cells and _______.

    muscle
    membrane
    film
    tissues
  • The bone marrow in the long bones helps in the production of red blood cells (RBCs). It helps to _______ oxygen.

     

    ;i:1;s:4:
    ;i:2;s:5:
    ;i:3;s:5:
  • The place where two or more than two bones are_______ with each other to form a junction is called joints.

    jointed
    combiend
    connected
    attched
  • Those joints which do not move at all is known as ________ joints.

    immovable
    fixed
    solid
    stayable
  • The joints which can be moved partially is known as semi-movable joints. With the help of cartilage, bones are able to move ________ .

    slightly
    lightly
    somewhat
    imprectibly
  • It is also called synovial joints as they contain synovial liquid in the _________.

    strength
    layar
    membrane
    film
  • A joint is formed from two bones where an end part of a bone is in the shape of a ball and the hollow of another bone is called ball and ______ joint

    joint
    standard
    socket 
    support
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