Body Movements: science class six
Human body and its movement
All animal have movement. Animals move from one place to other place in search of food, in search of suitable environment, in search of water, in search of partners, and to protect themselves from enemies, etc.
Locomotion and Movement
Movement of whole body from one place to other place is called locomotion, while change in the position of part of body with respect to whole body is called movement. Movement is a characteristic feature of all living things.
There are many kinds of movements in our body. For example, human blink their eyes, heart beats, breathing air, eating food, turning head etc.
These types of movements possible in our body are because of presence of joints between two bones.
Skeletal system
Some animal has a skeletal system.
All animals are not similar in shape. Animals have different shape because of difference in their skeleton. Skeleton gives an animal a particular shape. Similarly, our body has a peculiar shape because of our skeleton. Without skeleton our body would be a lump of flesh.
Human Skeleton (Fig-1)
Skeleton of human is hard internal framework of bones and cartilage. An adult person skeleton comprises of 206 bones, while a child skeleton has 300 bones. Some bones of child skeleton fuses together as he becomes adult. These bones are collectively known as skeletal system. It works like a machine and give a particular shape to the body.
Our skeletal system mainly composed of a backbone or vertebral column. There are two girdles attached to the vertebral column. Limbs are attached to girdles. There is a rib cage for protecting lungs and heart. And on top of the vertebral column there is a skull.
Many animals have similar design of skeleton. All of them are called vertebrates. Some of them may not be having legs and hands. For example, fishes and snakes don’t have limbs. In birds there are just two legs. Their hands are modified into wings. Wings help birds in flying.
Different parts of skeleton are made for different purpose.
Skull
Skull is the uppermost part of the skeleton system. Skull gives the shape to our head. Bone of skull is most hard.
Human Skull (Fig-2)
The upper part of the skull works as brain box and it is also called so as it protects our mighty brain. The brain box is known as cranium. Other bones are called facial bones as it gives the shape to our face and jaw.
The lower jawbone can move. lower jawbonet is the only movable part of the skull. Skull has total 12 bones.
Rib cage
Rib cage protects our vital organs like heart and lungs. The rib cage has thin, flat and curved bones. It has a cylinder type structure.
Human Rib cage (Fig-3)
Rib cage has 24 ribs. Ribs are curved around from the backbone to the front of the body. Rib cage is attached to the back bone by soft bones which is called cartilage. As cartilage is a kind of soft bone, so it gives more flexibility to the rib cage, which helps during breathing.
Spinal cord
Spinal cord runs from the lower part of skull to the hipbone. Spinal cord is called the back bone and vertebral column also. Spinal cord helps to keep our body straight. Spinal cord also helps during walking, moving, sitting etc.
Human spinal cord (Fig-4)
There are 33 small disc type bones in the spinal cord, which are joined together. These small disc type bones are called vertebrae. The animals in which this vertebral column is present are called vertebrate. And animals in which vertebral column is not present are called invertebrate.
Hand bones
Hands' bones are joined with shoulder blades. Shoulder blades are called scapula also, which is attached with collar bones. Collar bones are known as clavicle. The combination of shoulder blades and collar bones is known as pectoral girdle, which is attached with vertebral column.
Human hand and shoulder joint (Fig-5)
The legs are joined with hip bones. Hip bones is known as pelvis. The pelvic girdle links the legs with the vertebral column. There are two sides of pelvic girdle which is known as hip bones.
Our two pair of hands and legs is called limbs. Our hands have upper arm, fore arms, wrist, palm, and fingers. The bone of upper arms are called humerus. The fore arms have two long bones, which are called radius and ulna. Our palm is made up of five bones. Each finger has three bones.
bones in human fingers(Fig-6)
The thigh, lower legs, ankles and foots are collectively known as legs. Legs are joined with hip bones. Each leg has one upper bone (thigh) which is called femur. The lower leg has two bones which are called tibia and fibula.
The lower leg is attached with the knee and the ankle bones. The knee cap is a small bone which is known as patella. The ankle is attached with the bones of the toes. All fingers of leg except the big toe has three bones each, the big toe has only two bones.
Movements in human body
Joints between two bones and muscles together enable us to move our parts of body. As joints of elbow, enable us to move our hand ups and down from the point of elbow. Joints between two bones of leg enable us to move our legs.
Some movements in our body depend upon our will, while some movements are automatic and we cannot control them. Movements which are in our control are called conscious movement. And movements of body which are automatic, are called unconscious movement.
Some automatic or unconscious movements in our body:
Circulation of blood in the body
Movement of the heart muscle
Movements of lungs for breathing
Movements of eye lids
Apart from the above movements walking, folding of hands, sitting etc are the movement, which depends on our will i.e. conscious movements.
Muscles
Muscle is contractile fibrous band or bundle. Muscle produces motion with the help of bone joints. We can see and feel our muscles by touching them near our arm, thigh, etc.
Muscles of human hand (Fig-7)
Our muscles work in pair. During the movement of body part; from joints one muscles relaxed while other muscle of the pair contracts.
During the movement of our arm at the point of elbow joint, two muscle, which are called biceps and triceps work together. When one muscle contracts other get relaxed and vice versa.
Joints
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support. Thus points where two or more bones joints are called bone joints or simply joints. For example, elbow joint, knee joint, ankle joint, etc.
Ligments
Ligaments are tissue which join with bones together. Ligament is very tough, flexible band of elastic tissues. Ligaments reduce friction between the two bones at the joints when bone moves.
Joints between two bones, muscles, and nervous impulse together are responsible for movement of the part of our body.
Reference:
All figures has been taken from ncert book class six science chapter body movements