GIVE THE NAMES OF TYPES OF JOINTS AND THEIR DEFINITION? GIVE THE FUNCTIONS OF SKELETON?
Joint is defined as a point connecting two or more bones. On the basis of movement, joints can be classifies as:
1) Fibrous or immovable joint:
These types of joints are only connected by ligaments thus, restricting their movement. For example the joint between the bones of the skull.
2) Cartilaginous or partially movable joints
Cartilaginous joints are the joints where the articulate bones are connected through cartilage. It allows slight movement. For example the joint between vertebrae is cartilaginous joint.
3) Synovial joint or movable joints
These are the movable joints of the body. They allow movement. Synovial joints are further classified into six types:
i) Hinge joints: These joints are present where the convex surface of one bone is connected to the concave surface of another bone. They provide flexibility and extension. For example knee joints.
ii) Ball and socket joints: These joints are present where round head of one bone is fitted into the hollow cup shaped socket of another bone. In addition to flexion and extension, they allow internal and external rotation. For example: shoulder joint.
iii) Gliding joint: These joints occur where the surface of one bone slide over the another one. These allow gliding movements. For example: joints between carpal bones.
iv) Pivot joint: These joints occur where a bony ring rotates around the pivot axis or where the end of one bone rotates around the axis of another bone. For example: palm of the hand.
v) Saddle joint: These joints allow the back and forth and side to side movement. For example: saddle joint connects the bones of the thumb.
vi) Condyloid joints: These joints connect many different bones together. For example: these joints are present in neck region.
Skeletal system is the body system which consists of bones, associated cartilage and joints. It serves various functions in our body. Some of these are:
- Movement: Muscles are attached to the bones and together they helps in our movement.
- Support: Skeletal system provides structural support to our body.
- Protection: It protects our internal organs like heart, lungs, brain.
- Blood cell production: The red bone marrow produces red blood cells, white blood cells and other blood components.
- Mineral storage: Various minerals like calcium are stored in bones.
- Energy storage: Fats are stored in the yellow bone marrow of long bones
1)Ball and socket joint
- This kind of joint is seen in shoulders, hip bone.
- In this joint the rounded end of one bone fits into the cavity (hollow space) of another bone.
- This allows movement in all direction.
- This kind of joint is present in our neck that joins had to body.
- This joint allows us to band our head forward, backward and turn left and right.
- A round ended bone slides in another shaped bone.
- This kind of joint is in our knees and elbows.
- It allows only back and forth movement.
- Joint in our body which cannot be moved are called fixed joint eg.upper jaw, skull.
1.Immovable joints are joints which do not allowmovement in them
2.Slightly movable joints allow little movement in them
3.Movable joints allow bones to move freely,these are mainly of 3 types
1.pivot joints allow bones to twist from one side to another
2.Ball and socket joint allow boes to rotate in a complete circle
3.Hinge joint allow back and forth movements in one direction only
These are the functions of the skeleton
1.It supports the body and gives it a definite shape
2.It protects delicate and vital organs such as heart,brain,lungs etc.
3.Bones serve as storage area of minerals such as calcium and phosphorus
4.Along with muscular system it helps in movement and locomotion
5.Some bones of skeletal system contain bome marrow which produce blood cells.
- Fibrous joints connect bones without allowing any movement. The bones of your skull and pelvis are held together by fibrous joints. The union of the spinous processes and vertebrae are fibrous joints.
- Cartilaginous joints are joints in which the bones are attached by cartilage. These joints allow for only a little movment, such as in the spine or ribs.
- Synovial joints allow for much more movement than cartilaginous joints. Cavaties between bones in synovial joints are filled with synovial fluid. This fluid helps lubricate and protect the bones. Bursa sacks contain* the synovial fluid.
* to enclose within fixed limits
Ball and Socket
Ellipsoid joints are similar to a ball and socket joint. They allow the same type of movment to a lesser magnitude. The wrist is an ellipsoid joint.
Pivot joints allow rotation arround an axis. The neck and forearms have pivot joints. In the neck the occipital bone spins over the top of the axis. In the forearms the radius and ulna twist arround each other.