Support and movement

• Skeletal system or skeleton is defined as the framework of hard, articulated structures that provide physical support, attachment for skeletal muscles and protection for the bodies of animals
• Movement is a general term meaning the act of changing place or position by entire body or by its parts. There are two types of movements: movement of body, parts, and locomotion
• Locomotion is the movement of an animal as a whole from one place to another
• The skeletal system of some vertebrates, for example, arthropods is on the outside of body, and it’s called exoskeleton
• Like other vertebrates, the humans skeleton is on the inside of body and is called endoskeleton
• Bones and cartilage are made up of living cells. Bones have nerves and blood vessels in them .they grow and have the ability to repair themselves.
• The big functions of skeletal system protection, support, and movement in our body. Skeleton works very closely with the muscular system to help us move. Similarly skeleton provides protection to many internal organs for examples. Skull protects brain ,vertebral column protects spinal cord, and ribs protect most of our other internal orga… vertebral column also provides the main support to our body mass
• In some parts, the bony framework of humans skeleton is supplemented by cartilage
• Cartilage is a dense, clear blue white firm connective tissue (But less strong than bone)
• The cells of cartilage are called chondrocytes. Each chondrocyte lies enough fluid space called lacuna present in the matrix of cartilage. The matrix of cartilage also contains collagen fibre. Blood vessels do not enter cartilage.
• Cartilage and bone are types of connective tissue in animals. Most connective tissues contain collagen fibre in a in a matrix
• Tendons and ligaments are other connective tissues that contain tightly, packed collagen fibre
• There are three types of cartilage: Hyaline, Elastic, and Fibrous cartilage
• Hyaline cartilage is a strong yet flexible. It is found covering the end of the long bones ,in the nose, larynx, trachea, and bronchial tubes
• Elastic cartilage is similar in structure to hyaline cartilage. It is also quite strong but has elasticity due to a network of elastic fibre in addition to collagen fibre. It is found in epiglottis, pinna etc
• Fibrous cartilage is very tough and less flexible due to large number of thick collagen fibre present in knitted form. It is found in intervertebral discs.
• Bone is the hardest connective tissue in body support and protect the various parts of body, but also produce red and white blood cells and minerals
• The hard outer layer of a bone is called compact bone while the interior of bone is soft and porous. it is called spongy bone .spongy bone contains blood vessels and bone marrow.

  Like cartilage the matrix of bones also contains collagen. but it also contains minerals for example, calcium and phosphate. cartilage contains a single type of cell, whereas bones contain different types of cells. The mature bone cells are called osteocytes.
• Babies are born with about 300 soft bones. Some of these bones fuse together so that the adult skeleton has 206 hard bones.
• Andreas Vesalius(1514-1564) honoured for developing modern anatomical studies. Vesalius was born in Brussels, Belgium. he made many discoveries in anatomy, based on studies made by the dissection of human dead bodies. this book contained the most accurate depictions of the whole skeleton and muscles of the human body.