Summary
Bones, cartilage and joints that support the body, protect organs and allow movement.
In depth
206 bones in adults. Functions: support, protection, movement, mineral storage, blood cell production in red marrow. Axial skeleton (skull, spine, ribs) and appendicular skeleton (limbs, girdles). Cartilage covers joint surfaces.
Bone is a living tissue with collagen and mineral. Red marrow makes blood cells; yellow marrow stores fat. Fractures heal through callus formation.
Remember: bones are not inert; they remodel continually.
The skeleton has 80 axial bones (skull, vertebral column, rib cage) and 126 appendicular bones (limbs and girdles). Babies are born with about 270 bones, which fuse to give 206. Bone tissue is compact (dense, outside) or spongy (trabecular, with marrow cavities), and long bones grow at epiphyseal plates until adolescence. Cartilage covers joint surfaces.
The vertebral column has curves that absorb shock, with 33 vertebrae in total (7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral, 4 coccygeal). Common problems include fractures (which heal through a callus), osteoporosis, osteoarthritis and scoliosis. Calcium and vitamin D, as well as weight-bearing exercise, support bone health.
Example: the smallest bone is the stapes in the ear, and the longest is the femur.
Frequently asked questions
What is Skeletal System?
Bones, cartilage and joints that support the body, protect organs and allow movement.
Which area of biology covers Skeletal System, and how advanced is it?
Skeletal System is one of the 51 topics in Human Physiology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Bone Remodelling, Tissues and Organs, Joints and Movement.
Can you give an example of Skeletal System?
The skull protects the brain, ribs the lungs and heart.
What should I learn before Skeletal System?
Skeletal System is a Beginner topic, so no earlier topic is required. Other Beginner topics in Human Physiology that pair well with it include Homeostasis, Tissues and Organs, Muscular System.
What topics are related to Skeletal System?
The closest topics to Skeletal System are Bone Remodelling, Tissues and Organs, Joints and Movement, Excretory System. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Skeletal System?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Skeletal System. To practise the whole of Human Physiology, use the Human Physiology quiz.
How is Skeletal System different from Bone Remodelling?
Skeletal System: Bones, cartilage and joints that support the body, protect organs and allow movement. Bone Remodelling: Osteoclasts resorb and osteoblasts build bone continuously, controlled by hormones and stress. Read both side by side and note what each one explains.
How should I study Skeletal System step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Bone Remodelling and explain the difference aloud. Finally, take the Human Physiology quiz and come back to this page for any question you miss.