BONES
Definition of Bones
Bones are hard, rigid structures that form the skeleton of the body. They are made of
connective tissue, mainly composed of a protein framework (collagen) and minerals
(calcium and phosphate) that make them strong and hard.
Functions of Bones
1. Support – Bones provide a rigid framework that supports the body and gives it
shape.
2. Protection – They protect delicate organs (e.g., skull protects the brain, ribcage
protects heart and lungs).
3. Movement – Bones act as levers, and with the help of muscles and joints, they
allow movement.
4. Mineral storage – Bones store minerals like calcium and phosphorus, releasing
them when the body needs them.
5. Blood cell formation (hematopoiesis) – The bone marrow inside some bones
produces red blood cells, white blood cells, and platelets.
6. Fat storage – Yellow bone marrow stores fat, which serves as an energy
reserve.
7. Endocrine regulation – Bones release hormones (like osteocalcin) that help
regulate blood sugar and fat metabolism.
,Total number of bones
In the adult human body, there are 206 bones in total. 🦴
Breakdown:
● Axial skeleton (80 bones) – Skull, vertebral column, rib cage.
● Appendicular skeleton (126 bones) – Bones of upper and lower limbs,
shoulder girdle, pelvic girdle.
👉 In newborn babies, there are about 270 bones, but as we grow, some bones fuse
together (like bones in the skull and spine), reducing the number to 206.
TYPES OF BONES
Based on - Shape
1. Long Bones
● Definition: Longer than wide, with shaft (diaphysis) and two ends (epiphyses).
● Extra points:
1. Mostly made of compact bone (strength).
2. Contain bone marrow cavity (medullary cavity).
Examples:
● Femur (thigh bone)
● Humerus (upper arm bone)
● Tibia (shin bone)
, 2. Miniature Long Bones
● Definition: Small but shaped like long bones, found in hand and foot.
● Extra points:
1. Lack a medullary cavity.
2. Help in fine, precise movements.
● Examples:
1. Metacarpals (hand)
2. Metatarsals (foot)
3. Phalanges (fingers and toes)
3. Short Bones
● Definition: Nearly equal in length, breadth, and thickness.
● Extra points:
1. Consist mainly of cancellous (spongy) bone with a thin outer layer of
compact bone.
2. Provide stability with little to no movement.
Examples:
● Carpals (wrist bones)
● Tarsals (ankle bones)
● Talus (ankle bone that joins tibia/fibula)
Definition of Bones
Bones are hard, rigid structures that form the skeleton of the body. They are made of
connective tissue, mainly composed of a protein framework (collagen) and minerals
(calcium and phosphate) that make them strong and hard.
Functions of Bones
1. Support – Bones provide a rigid framework that supports the body and gives it
shape.
2. Protection – They protect delicate organs (e.g., skull protects the brain, ribcage
protects heart and lungs).
3. Movement – Bones act as levers, and with the help of muscles and joints, they
allow movement.
4. Mineral storage – Bones store minerals like calcium and phosphorus, releasing
them when the body needs them.
5. Blood cell formation (hematopoiesis) – The bone marrow inside some bones
produces red blood cells, white blood cells, and platelets.
6. Fat storage – Yellow bone marrow stores fat, which serves as an energy
reserve.
7. Endocrine regulation – Bones release hormones (like osteocalcin) that help
regulate blood sugar and fat metabolism.
,Total number of bones
In the adult human body, there are 206 bones in total. 🦴
Breakdown:
● Axial skeleton (80 bones) – Skull, vertebral column, rib cage.
● Appendicular skeleton (126 bones) – Bones of upper and lower limbs,
shoulder girdle, pelvic girdle.
👉 In newborn babies, there are about 270 bones, but as we grow, some bones fuse
together (like bones in the skull and spine), reducing the number to 206.
TYPES OF BONES
Based on - Shape
1. Long Bones
● Definition: Longer than wide, with shaft (diaphysis) and two ends (epiphyses).
● Extra points:
1. Mostly made of compact bone (strength).
2. Contain bone marrow cavity (medullary cavity).
Examples:
● Femur (thigh bone)
● Humerus (upper arm bone)
● Tibia (shin bone)
, 2. Miniature Long Bones
● Definition: Small but shaped like long bones, found in hand and foot.
● Extra points:
1. Lack a medullary cavity.
2. Help in fine, precise movements.
● Examples:
1. Metacarpals (hand)
2. Metatarsals (foot)
3. Phalanges (fingers and toes)
3. Short Bones
● Definition: Nearly equal in length, breadth, and thickness.
● Extra points:
1. Consist mainly of cancellous (spongy) bone with a thin outer layer of
compact bone.
2. Provide stability with little to no movement.
Examples:
● Carpals (wrist bones)
● Tarsals (ankle bones)
● Talus (ankle bone that joins tibia/fibula)
