The skeletal system provides a supportive framework, enables movement, protects important organs, and stores essential materials. This lesson introduces the system’s main functions and explains how the skeleton is divided into the axial and appendicular portions.
The skeletal system includes all the bones, cartilages, and ligaments of the body. These structures support and give shape to the body and its parts. The skeleton refers specifically to the body’s bones. An adult skeleton usually contains 206 bones. Younger people have more separate bones because some bones fuse during childhood and adolescence.
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What is the difference between the skeletal system and the skeleton?
The skeletal system includes bones, cartilages, and ligaments. The skeleton refers specifically to the bones of the body.
What are the major functions of the skeleton?
It supports the body against gravity, provides a framework for muscle-driven movement, protects internal organs, stores minerals such as calcium and phosphate, and contains marrow that stores fat and houses blood-cell-producing tissue.
What is the axial skeleton, and how many bones does it contain in an adult?
The axial skeleton forms the central vertical axis of the body and includes bones of the head, neck, chest, and back. It contains 80 bones in an adult.
What is included in the appendicular skeleton?
It includes all bones of the upper and lower limbs and the bones that attach each limb to the axial skeleton. It has 126 bones in an adult.
Why do younger people have more separate bones than adults?
Some bones that are separate during childhood and adolescence fuse together as development proceeds, resulting in the adult arrangement of 206 bones.
Quiz questions
What structures are included in the skeletal system?Answer: Bones, cartilages, and ligaments.
How many bones are usually present in the adult skeleton?Answer: 206 bones.
Which description identifies the axial skeleton as a whole?Answer: The central division containing bones of the head, neck, chest, and back.
How does the skeleton help muscles produce body movement?Answer: It provides muscle attachment and leverage, allowing muscles to act on bones.
What is a function of bone marrow?Answer: It stores fat and contains blood-cell-producing tissue.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.