Skeletal System Overview

Study Notes

The skeletal system is a system of organs that provides support, protection, and movement for the body.
It consists of 206 bones that make up the skeleton.

Support: Provides a framework for the body's muscles, organs, and tissues.
Protection: Protects internal organs, such as the heart, lungs, and brain, by encasing them in a cage of bones.
Movement: Acts as a system of levers and joints that enable movement and locomotion.
Blood cell production: The bones in the skeletal system are responsible for producing blood cells.
Storage of minerals: Bones act as a storage site for minerals such as calcium and phosphorus.

Long bones: Characterized by a long shaft and ends that are wider than the shaft. Examples: femur, humerus.
Short bones: Cube-shaped bones that provide support and stability. Examples: carpals, tarsals.
Flat bones: Thin, flat bones that provide protection and support. Examples: ribs, sternum.
Irregular bones: Bones that do not fit into any of the other categories. Examples: vertebrae, pelvis.

Compact bone: Dense, compact tissue that forms the outer layer of bones.
Cancellous bone: Spongy, porous tissue that forms the inner layer of bones.
Bone marrow: The spongy tissue inside bones that produces blood cells.
Periosteum: A layer of connective tissue that covers the surface of bones.
Endosteum: A layer of connective tissue that lines the inner surface of bones.

Types of joints:
- Synovial joints: Freely movable joints that have a space between the bones. Examples: shoulder, elbow, knee.
- Cartilaginous joints: Joints that are connected by cartilage. Examples: joints between vertebrae.
- Fibrous joints: Joints that are connected by fibrous connective tissue. Examples: joints between bones in the skull.
Joint movements:
- Flexion: Bending movement that decreases the angle between bones.
- Extension: Straightening movement that increases the angle between bones.
- Rotation: Rotational movement around a single axis.
- Circumduction: Circular movement that combines flexion, extension, and rotation.

The skeletal system consists of 206 bones that provide support, protection, and movement for the body.

Long bones: characterized by a long shaft and wider ends (e.g., femur, humerus)
Short bones: cube-shaped, providing support and stability (e.g., carpals, tarsals)
Flat bones: thin and flat, providing protection and support (e.g., ribs, sternum)
Irregular bones: don't fit into other categories (e.g., vertebrae, pelvis)

Types of joints:
- Synovial joints: freely movable with space between bones (e.g., shoulder, elbow, knee)
- Cartilaginous joints: connected by cartilage (e.g., joints between vertebrae)
- Fibrous joints: connected by fibrous connective tissue (e.g., joints between bones in the skull)
Joint movements:
- Flexion: bending, decreasing the angle between bones
- Extension: straightening, increasing the angle between bones
- Rotation: rotational movement around a single axis
- Circumduction: circular movement combining flexion, extension, and rotation