The Skeletal System.
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The Skeletal System Skeletal system - The skeletal system is the system of interconnecting bones which form the rigid framework of the human body. The skeletal system not only provides the body with form, but also protects and supports its soft organs and tissues. It also provides attachments for muscles and serves as a system of levers essential for locomotion. The functions of the human skeleton are: * To provide shape for the body. * To provide support for the body. * To protect delicate organs e.g. brain. * To provide a large surface area for the attachment of muscles. * To provide a lever system through which muscles can pull. * To provide a large surface area of the attachment of muscles. * To manufacture red blood cells and to store fat, calcium and phosphate. Here is a labelled diagram of the human skeleton: The human skeleton is divided into appendicular skeleton and axial skeleton. Axial Skeleton Appendicula Skeleton * Cranium * Mandible * Scapula * Ribs * Spinal column * Pelvis * Carpals * Radius * Ulna * Humerus * Pectoral girdle * Femur * Tibia * Fibula * Tarsal Components of bones Examples of each type of bone are shown below in diagram. Bone is the hardest connective tissue in the body, mainly because it contains deposits of calcium phosphate and calcium carbonate. Bone acts as a store for calcium, and as a result of regular exercise more calcium is deposited, increasing bone density. ...read more.
This area allows the greatest amount of movement of bending forwards, backwards and side to side. This is also the most common area for back injuries due to the amount of movement and is an area which should be especially worked upon for flexibility exercises. Sacral vertebrae - there are five vertebrae in this region which are fused together to become one. This is where the pelvis is joined to the spine and where the body mass is transmitted to the hips and legs. Coccyx (tail) - there is four vertebrae fused together and is the base of the spine. It is all that remains of what was a tail before humans evolved, hence the name 'tail bone'. The general functions of the spine are: * To keep the body upright * To help posture and movement * To act as a shock absorber * To protect the spinal column. Joints "The point of connection between two bones or elements of a skeleton (especially if the articulation allows motion)" www.cogsci.princeton.edu/cgi-bin/webwn There are 3 main types of joints: * Fibrous joints (or Sutured) - are very stable joints in which the bones are joined by very strong fibres allowing no observable movement e.g. the sutures in the skull (honeybourne et el. 2000) www.science.ubc.ca * Cartilaginous joints - are joined by a tough, fibrous cartilage which provides stability but also allowing a small degree of movement e.g. intervertebral disks www.37c.com.cn/education * Synovial joints - are the most common type of joint in the body, allow a wide range of movement in most cases although some (e.g. ...read more.
These movements are given special names; Flexion -Bending the joint to make the angle between the two bones smaller. When you touch your right shoulder with your right hand, your elbow is in flexion (flexed). Extension - Straightening a joint to make the angle larger. If you straighten your legs, the knees have undergone extension (extended). Abduction - Moving away from the median plane. When you stand with your feet apart, your legs are in abduction (abducted). Adduction - The opposite of abduction. If you sqeeze your knees together, you are adducting your legs. Circumduction - A circular motion combining flexion, extension, abduction and adduction. Making circles in the air with your arms Rotation - is the movement of bone around a central axis. For instance, the arm has both internal and external rotation. Supination - A movement of the forearm in which the palm faces posteriorly. It is when your palms are faced up. Pronation - A movement of the forearm in which the palm faces anteriorly. It is when your palms are faced down. Eversion - is the movement of the sole of the foot outward at the ankle Inversion - is the movement of the sole of the foot inward at the ankle. Dorsiflexion - Movement of the ankle in the sagittal plane which decreases the angle between the foot and the lower leg when you point your foot towards your head. Plantarflexion - Movement of the ankle in the sagittal plane which increases the angle between the foot and the lower leg when you stand on 'tip-toes' your ankles are in plantar flexion. ...read more.
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