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The functions of the skeletal system

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Bone is a mineralized and hard organ that forms the skeleton of vertebral animals. Bone exerts important functions in the body such as support and protection of soft tissues, calcium and phosphate storage, harboring of the bone marrow and locomotion1.

Bones provide structural support for the body and help to define our shape. The human skeletal system also provide protection to the vital organs e.g Skull provides support and protection to the brain and rib cage provides protection to heart and lungs. Bone marrow also produces white blood cells and red blood cells of the immune system2.

The human skeleton has 206 bones of different sizes and shapes. Bones such as those in arms and legs are called long bones. Others, like those in the skull, are called flat bones. Adult human bone is composed of 30% organic matter and 70% minerals3.

The functions of bone can be summarized into as follows:

1. Shape
2. Support
3. Protection
4. Blood cell production
5. Movement

Just imagine for a second, if we don't have bone, our body would be a high volume hairy balloon wiggling and jiggling whenever anyone pokes you. Bone gives our body shape. It determines our height, length of our hands and foot4.

Bone also plays a pivotal role in supporting vital organs of our body. The skull supports the brain, chest cavity supports the lungs and heart and abdominal cavity supports gastrointestinal tract, kidneys and urinary bladder which is very crucial in maintaining the function of these organs.

Bone is a hard and rigid structure but at the same time, it has flexibility in it. The flexibility is due to collagen fibres. This combination of rigidness and flexibility provides protection to the vital organs against blow and trauma5.

Bone has the ability to produce blood cells due to the soft bone marrow present in it. There are two types of bone marrow present in the human skeleton, each one with its own function

1. Red bone marrow
2. Yellow bone marrow

The red bone marrow produces red blood cells with the rate of 200 million red blood cells per day and some white blood cells. Red blood cells are necessary to carry oxygen to each and every cell of the body and white blood cells are important in fighting against disease. The main sites for red bone marrow are skull, ribs and vertebrae in adults. The other type of bone marrow is yellow bone marrow which is fat primarily and can be converted into red bone marrow if needed and when needed6.

Bone provides the facility of movement to our body with the help of muscles. With the musculoskeletal system, the human body can do locomotive motion and movement of the parts of the body. The shape of bones and the joints play important role in variety of movements at different joints we enjoy. For example, the ball and socket movement of the shoulder joint allows movement of the upper limb in almost all directions while the shape of hip joint allows a bit limited movement as compared to shoulder joint7.

References
1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4515490/
2. https://www.ncbi.nlm.nih.gov/books/NBK45504/
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2760485/
4. https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0022807/
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781230/
6. https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0022007/
7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152283/

Topics: skeletal system

Dr. Owais Amin

Written by Dr. Owais Amin