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Introduction

The skeletal system the framework within the human body that supports are body and it is what makes us stand up. Without this we would be no more than a human blob on the floor which would be unable to move. The skeleton is not just for support; on the other hand it is used for protection of all the vital organs (cardiac and respiratory), bodily kinetics, and is also home to the framework which makes all the organs function called the brain. A fully formed skeleton is formed of 206 bones from head to toe and each of these bones varies in size and importance. In the skeleton there are different types of bones and they all have different shapes according the function they carry out and where they are placed: Long Bones-These consist of a hollow shaft of hollow bone, which in the ends of this, proximally and distally, consists of spongy cancellous bone. Muscles are attached to these to help with movement. Short Bones-They are irregularly cube shaped and are mainly cancellous bone which is covered by compact bones on the outside like a Christmas present with the wrapping on the outside and the present on the inside. Flat bones-the main jobs of flat bones is to protect vital internal organs and also they provide excellent muscle attachment areas for muscles. Irregular bones-they have a variety of shapes and sizes and they also have a variety of jobs to perform on the skeleton depending on where they are and their function. Sesamoid bones-They are specialised bones that assist joint movement and these are covered with articular cartilage. ...read more.

Middle

The phalanges do not really have individual names but are named after the digit, and their distance from the body. Distal phalanges are at the tips of the fingers and toes. Proximal phalanges are closest to the hand (or foot) and articulate with the metacarpals of the hand, or metatarsals of the foot. Middle or Intermediate phalanges are between the distal and proximal. The thumb and big toe do not have middle phalanges. The term phalanx or phalanges refers to a Greek army formation in which soldiers stand side by side, several rows deep, like an arrangement of fingers or toes. Pelvic gurdle (flat bone)-The pelvis (pl. pelvises or pelves) is the bony structure located at the base of the spine. The pelvis incorporates the socket portion of the hip joint for each leg. The pelvis is symmetrical and each side is actually made up of three separate bones: the upper half (the broad "wings") is the ilium the middle (the top half of the lower "loops") is the pubis the bottom (the lower half of the "loops") is the ischium These three bones fuse together with age and are collectively known as the hip bone, os coxae, or the innominate bone. The pelvis is joined to the sacrum bone by ligaments (the sacroiliac joint), and the hip bones nest in specially shaped sockets (the acetabulum) on each side. The upper edge of the ilium is known as the iliac crest. The place at the front of the pelvis where both pubis bones join together is called the symphisis pubica. This is normally a very inflexible joint, but it softens and becomes more flexible during late pregnancy, allowing it to expand during labour for the baby's head to pass through. ...read more.

Conclusion

It is these that give bone its well known properties. Also collegen fibres give bones the ablity to bend making it less brittle. There are a lot of bones in human anatomy but they are all made up of two types of essential bone tissue. These are: Compact or cortical tissue This type of tissue is the so called armour of the bone. The way compact bones is structured it is built to bear the weight of the body and protect it from breakages through the long bones. Cancellous or spongy bone This is held in the epiphysis of a bone and this is where red blood cells are produced. This type of bone tissue looks like a sponge but the only thing is that it is not soft it is very hard. All bones are inside a important membrane called the periosteum. This contains blood vessels to deliver the necessary foods for the bone to develop. Inside the bone and the periosteum there are 3 different types of cells and they are: Osteoblasts This is also known as the building blocks for bones. It produces collagen and minerals (i.e. calcium) to assist with healthy development. Osteocytes This is the prinicpal cell for bone tissue and is improtant for healthy development of bones. Osteoclasts This type of bone can be reffered as the pac men of the bone and they remove parts of the bone they no longer see healthy or fit. For everyone, they are not born with fully formed bones anywhere in the bondy they all start as cartilage. During infancy, calcium and phosphrous are laid and the bones start to eventually calcify (harden). A bone develops from the central parts out edge and has a honeycombed innner networked mesh and an outer compact layer of bone. Ossification is where the bone development occurs. ...read more.

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