Skeletal and Nervous System
Bone Joints
Points where two bones meet are called joints. A joint is the points in skeleton where the two bones are connected together. Bones are very hard they cannot be bent; but we bent our bones with the help of these joints.
Bones are connected to each other at joints by strong fibrous tissue. These fibrous tissues which connect bones are called ligaments.
Most of the joints are movable. There are four kinds of movable joints in our body.
BALL AND SOCKET JOINT
Ball and socket joint comprises of ball and socket. Ball and socket joints are similar joint you find in your joy stick to play video game. Such joints you can see also in the gear of car or other motorized vehicles.
The round ball like end of a bone fits into the same size of socket of the other bone. This kind of joint is called ball and socket joint. Ball and socket joint allows movement in many directions. The hip joint and the shoulder joint are the example of the ball and socket joints.
Hinge Joint
The bones of this joint allow the movements only in one direction like the hinges of a door. Hinge joints are found in our body in knee and foot, fingers, toes and elbow.
Pivot joints
Pivot joints are found in the skull and the first two vertebrae. It helps in movement of our heads ups, down, and sideways. Because of this joint we can move our head ups, down and sideways. Have you ever think that what happened if we would not have such pivot joints.
Gliding joints
Gliding joints are found in the bones of the wrist and the ankle. Gliding joints allow our wrist and ankle bones slide against each other.
Cartilage
There are many other small bones found in our body, which are soft and elastic. These soft and elastic bones are called cartilage. Cartilage makes the ends of the bones smooth which helps in the smooth movements. Without cartilage, the bones would rub against each other. Some organs like nose, ears have cartilage.
Muscles
Muscles are fleshy tissues found at some parts of our bones. Bones are joints with the help of strong muscles which help in movements. There are three types of muscles in our body.
Skeletal muscles
Skeletal muscles are found in arm. Only skeletal muscles are in our control directly. If we think to move our arm; we can actually do it.
Cardiac muscles
Cardiac means heart so cardiac muscles present in our heart. Cardiac muscles make the heart beat. Cardiac muscles are not in our control as we do not have to order our heart to beat. Cardiac muscles work automatically to whole life.
Smooth muscles
Smooth muscles also work automatically. Smooth muscles are present in our digestive system.