Mayur Deshpande
  Personal trainer in Mumbai
Learn Human BodySkeletal System

Learn Human Body

Skeletal System


What is a bone?

What are the functions of bones?

What is a bone made of?

Are bones alive?

Who has more bones a baby or an adult?

What is vertebral column?

What is a joint?

What are the different types of joints?

Terms use in skeletal systems


What is a bone?

Bones are rigid organs that form part of the skeleton system. Bones function to move, support, and protect the body, produces red and white blood cells and store minerals. Bones come in a variety of shapes and have a complex internal and external structure, allowing them to be lightweight yet strong and hard, while fulfilling their many other functions.bones may be classified acoordling to their shape;long,short,flat and irregular bones.
Long bones - the bones of the arms, legs, hands, and feet (but not the wrist or ankles). The Shaft of the Long Bones is the DIAPHYSIS, and the Ends are called EPIPHYSIS. The Diaphysis is made up of Compact Bone and is Hallow, forming a canal within the shaft. This Marrow Canal contains Yellow Bone Marrow, which is mostly adipose tissue. The Epiphyses are made of Spongy Bone covered by a thin layer of Compact Bone.
Short bones - the bones of the wrist and ankles.
Flat bones - the ribs, shoulder blades, hipbones, and cranial bones.
Irregular bones - the vertebrae and facial bones.


What are the functions of bones?

Support- The main job of the skeleton is to provide support for our body. Without your skeleton your body would collapse into a heap.
Protection- Your skeleton also helps protect your internal organs and fragile body tissues. The brain, eyes, heart, lungs and spinal cord are all protected by your skeleton. Your cranium (skull) protects your brain and eyes, the ribs protect your heart and lungs and your vertebrae (spine, backbones) protect your spinal cord.
Movement- Bones provide the structure for muscles to attach so that our bodies are able to move. Bones also provide a system of levers (rigid rods that can be moved about a fixed point) on which a group of specialized tissues (Muscles) act to produce motion.
Storage Site of Inorganic Salts- Such as CALCIUM. Calcium may be removed from bone to maintain a normal blood calcium level, which is essentially for blood clotting and proper functioning of the muscles and nerves.


What is a bone made of?

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A typical bone has an outer layer of hard or compact bone, which is very strong, dense and tough. Inside this is a layer of spongy bone, which is like honeycomb, lighter and slightly flexible. In the middle of some bones is jelly-like bone marrow, where new cells are constantly being produced for the blood. Calcium is an important mineral that bone cells need to stay strong.


Are bones alive?

Yes, Old bones are dead, dry and brittle. But in the body, bones are very much alive. They have their own nerves and blood vessels, and they do various jobs, such as storing body minerals like calcium. Bones are made of a mix of hard stuff that gives them strength and tons of living cells which help them grow and repair themselves.


Who has more bones a baby or an adult?

Babies have more than adults! At birth, you have about 300 bones. As you grow older, small bones join together to make big ones. Adults end up with about 206 bones.


What is vertebral column?

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As stated above Axial bones consists vertebral column and thorax .vertebral column provides the main support for the body and also protects the central nervous system and vital organs in the chest region.The adult vertebral column consists of 33 vertebrae divided into five groups according to the region of the body in which they are located. A typical vertebra consists of two essential parts: an anterior (front) segment, which is the vertebral body; and a posterior part - the vertebral (neural) arch - which encloses the vertebral foramen.The upper 7 are cervical(neck) vertebrae,followed in descending order by 12 throracic vertebrae,5 lumber vertebrae ,5 sacral vertebrae fused into one bone as the sacrum. The adult vertebral column has four major curvatures two primary curves-thoracic & sacral and two secondary curves-cervical and lumber.


What is a joint?

Joint is a place where two bones comes together, permitting the bones to move without damaging each other. Joints are responsible for keeping bones far enough apart so they do not rub against each other as they move. At the same time, joints hold the bones in place.


What are the different types of joints?

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Immovable joint; they are often called fixed joints, and allow no movement between bones. These joints are interlocked and held together by connective tissue, or they are fused together. The places where the bones of the skull meet (suture) meet are examples of immovable joints.
Slightly movable joint or semimovable joints these joints permit a small amount of movement. These bones are farther apart from each other than immovable joint bones. The joints between the two bones of the lower leg (tibia and fibula) and the joints of the vertebrae are examples of slightly movable joints.
Freely movable joint. Most of the joints of the body are freely movable joints. Freely movable joints are grouped according to the shapes of surfaces of the adjacent bones. There are six types of freely movable joints:
•Ball & socket joint- Permits circular movement - the widest range of movement. The shoulder & hip Joint, which enables you to move your arm up, down, forward and backward, as well as to rotate it in a complete circle.
• Hinged joint- Permits a back-and-forth motion. The Knee enables your leg to flex and extend. The Elbow, which allows you to move your forearm forward and backward.
• Pivot joint - Permits rotation of one bone around another. The elbow enables your hand to turn over. It also allows you to turn your head from side to side.
• Gliding joint - Permits a sliding motion of one bone over another. Found at the ends of the collarbones, between wrist bones, and between anklebones.
•Saddle joint- Permits movement in two planes. This type of joint is found at the base of the thumb.
Ellipsoid joint - allows for a hinge type movement in two directions. The joints that connect fingers with the palm and toes with the soles of feet are examples.


Terms use in skeletal systems

Ligament- Fibrous tissue that connects bones (or two different parts of a single bone). They are sometimes called "articular ligaments".
Tendon- A tendon (or sinew) is a tough band of fibrous connective tissue that connects muscle to bone or muscle to muscle and is designed to withstand tension.
Cartilage- The end of each bone is covered with articular cartilage. This is a tough material that cushions and protects the ends of the bones. When it degenerates, arthritis develops.It is harder than ligaments, softer than bone
Synovial fluid- A clear fluid secreted by membranes in joint cavities, tendon sheaths, and bursae, and functioning as a lubricant.
Meniscus- The meniscus is cartilage tissue that protects and helps promote flexibility in the human knees. The meniscus has a half moon shape, and there are two in each knee.
Synovial membrane- Around each joint is the synovial sac(membrane) which protects the joint and also secretes the synovial fluid. Synovial fluid serves to protect the joint, lubricate the joint.
Bursa- A bursa is a little fluid sac that helps the muscles and tendons slide freely as the knee moves.