Human Anatomy: Skeleton

For a common man, a day is packed with a lot of activities. Being at same position or place, one cannot carry out all these activities. Hence, we need to change our position or move from one place to another. A human body exhibits a variety of movements like walking, bending, crawling, running, jumping, and so on. Even when we are sitting idle, we can sense some types of movements in us. What makes us capable of doing activities is what we are framed of the viz. skeleton. Human anatomy is very deeper than what we see from outside.

Human Skeleton

Human Skeleton

Skeleton and Locomotion

Locomotion in generally is referred as a process of movement from one place to another. While the locomotion of a human body is put together by an effort of bones and muscles. The human body has a collection of bones called skeletons beneath muscles, skins, internal organs. This skeleton system supports and shapes the human body.

A human body is composed of 206 bones that are mainly involved in the locomotion and in protecting several vital organs.The skeleton of a fish is different from that of a human which is in turn different from that of a bird. The skeleton of an organism varies from organism to organism depends on their type of movement. This skeletal system frames whole body as well as support.

Joints are points at which two bones meet. They help in easy and convenient movements in our body like bending, rotation, writing, running, etc.  Based on flexibility and mobility, joints can be further classified into movable joints and immovable or fixed joints. Movable joints are flexible while fixed joints are joints where bones are fused and non-flexible. 

Parts of the Skeletal System

The Axial and Appendicular skeleton.

The skeletal system has two unique parts:

  • The axial skeleton

This skeleton system continues along the body’s central axis. The axial skeleton is composed of 80 bones. They include:

  1. 22 bones in the skull.
  2. 7  bones in the hyoid.
  3. 25 bones in the rib cage.
  4. 26 bones in the vertebral column.
  • Appendicular skeleton.

The appendicular skeleton consists of the limbs and girdles. It made up of 126 bones and is divided into six major regions which includes

  1. 4 bones inside the shoulder girdle.
  2. 6 bones in the arm and forearm.
  3. 54 bones in the hands.
  4. 2 bones in the pelvis or pelvic region.
  5. 8 bones in the legs.
  6. 52 bones in the foot.

Muscles

Muscles are specialized tissues which assist bones in locomotion. Muscles cover the bones present in our body and are attached to bones by the tissues called tendons. Muscles and bones together help us in movements.

Bending and stretching of a body part is an outcome of contraction and relaxation of corresponding muscles present in that region. Joints help in the flexibility of bones but a bone could not be bent or stretched until a muscle acts on it. When we have to bend a body part, muscles attached to that bone pulls it to the direction of movement. This is because a muscle can only pull they always work as a pair. For example, when we bend our arm, muscles at that region contract, become shorter and stiffer and pull the bones to the direction of movement. Then for relaxation (stretching), muscles at opposite direction have to pull the bones towards it.

Skeleton : Muscle Movement

Muscle Movement

Muscles and bones are a combination of locomotion, but this combination is not necessarily always happen especially in boneless animals.

For more detailed information about the human body, visit Byju’s.

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Practise This Question

Regarding Assertion[A] and Reason[R].Choose the correct option.

Assertion [A]: Locomotion is the movement of an individual from one place to place.

Reason [R]: All Locomotions are movements but all movements are not locomotion.