The Human Skeletal System
The human skeletal system is comprised of both fused and individual bones; supported and supplemented by ligaments, tendons, muscles and cartilage. The skeletons purpose is to protect and support the delicate internal organs and provide a framework that allows the body to stand upright and move. It also produces blood cells and stores minerals that our body needs to function effectively.
The skeletal system is a very important part of the human body. Without the skeleton humans would be immobile and even a small impact on the head or chest would cause serious injuries, to the internal organs.
The skeletal system is very complex. It contains many elements that work in union together in order for the body to function effectively. The skeletal system is made up of many different parts; from the cells and bone marrow to the bones, ligaments, tendons and cartilage. The skeleton also has joints that, with assistance from muscles, help the body to move around.
Anatomy & Physiology- Structure of bone
Bone consists of both living tissue and non-living substances. At its most basic level it is made up of cells, salts and minerals. Bone is also made up of two different kinds of bone tissue as well as marrow.
Cells- Bone is a dynamic tissue that is continually being built, broken down and rebuilt in a process known as bone remodelling. • Osteoblasts- These are cells responsible for the production of new bone tissue. They are thought to be derived from cells found to be associated with blood vessels. • Osteoclasts- These are multinucleated cells that break down bone. They are derived from monocytes which originate in bone marrow. They play an important role in liberating minerals and other molecules stored within the bone matrix. • Osteocytes- These are osteoblasts that have been embedded within the matrix. Osteocytes engage in metabolic exchange with the blood that flows through the bones.
Bone Marrow- There are two types of bone marrow found in bone. These are: • Red Marrow- This type of marrow is also known as myeloid tissue and produces red blood cells, platelets and most white blood cells. • Yellow Marrow- This type of marrow stores fat (it is yellow in colour due to the high concentration of fat cells), produces some white blood cells and can turn into red marrow when needed.
Bone Tissue- There are two different kinds of bone tissue. These are: • Compact Bone- This type of bone tissue is dense, smooth and very strong. • Cancellous Bone- This type of tissue is spongy and light weight. Cancellous bone is also where red marrow can be found.
Salts & Minerals- Bone also contains several types of salts and minerals, some of the most common being calcium and phosphate.
Anatomy & Physiology- Bone Classifications
At birth the human skeletal system is comprised of around 300 individual bones, many of these bones fuse together as growth occurs. By adulthood the human skeleton contains around 206 fused and individual bones. These bones can be classified into five different types:
Long Bones- These bones are some of the longest bones found in the human skeleton, such as the femur, humerus and tibia, but are also some of the smallest, including the metacarpals, metatarsals and phalanges.
The classification of a long bone includes having a body which is longer than it is wide, with a main shaft composed of hard compact bone called the diaphysis and two ends made up of cancellous bone called epiphysis. Inside the diaphysis is the medullary cavity, this cavity is where yellow marrow is primarily found.
Short Bones- The primary function of the short bone is to provide support and stability with little movement. Examples of this type of bone are the carpals and tarsals (the wrist and foot bones). Short bones are defined as being approximately as wide as they are long. They consist of only a thin layer of compact...
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