Ch: 2 Skeletal System

Skeletal System

The framework of bones that supports the human body.

Bone

One of the hardest substances in the human body, forming the skeletal structure.

Adult Skeleton

Contains 206 bones after some bones fuse together from approximately 270 at birth.

Femur

The largest bone in the human body, found in the thigh.

Stapes

The smallest bone in the human body, located in the ear.

Vertebral Column

Also known as the backbone, made of 33 vertebrae and supports the body.

True Ribs

The first seven pairs of ribs attached directly to the sternum.

False Ribs

The eighth, ninth, and tenth pairs of ribs that are indirectly attached to the sternum.

Floating Ribs

The eleventh and twelfth pairs of ribs, which are not attached to the sternum.

Pelvic Girdle

A ring of bones that supports the weight of the upper body and connects the legs.

Achilles Tendon

The largest tendon in the body, connecting the calf muscle to the heel bone.

Articular Cartilage

A tough, elastic substance found between two bones at joints, acting as a shock absorber.

Joint

The place where two bones meet; can be fixed, slightly movable, or freely movable.

Pivot Joint

Allows one bone to rotate within a ring-like structure formed by another bone.

Hinge Joint

Allows back-and-forth movement, similar to the opening and closing of a door.

Ball-and-Socket Joint

Allows movement in nearly all directions, found in shoulders and hips.

Skeletal Muscles

Muscles attached to bones through tendons, allowing voluntary movement.

Cardiac Muscles

Involuntary muscles found only in the heart, working continuously without control.

Smooth Muscles

Involuntary muscles found in organs like the digestive system and blood vessels.

Calcium

An essential mineral necessary for building strong bones.

Vitamin D

Vitamin needed for calcium absorption, produced in the body when exposed to sunlight.

Posture

The position in which someone holds their body while standing, sitting, or walking.

Osteoblasts

Cells responsible for bone formation.

Osteoclasts

Cells that break down bone tissue.

Cartilage

A flexible tissue that provides support and cushioning in joints.

Ligament

A fibrous connective tissue that connects bones to other bones at joints.

Tendon

A fibrous connective tissue that connects muscles to bones.

Bone Marrow

Soft tissue inside bones where blood cells are produced.

Calcium Phosphate

A chemical compound that provides strength and rigidity to bones.

Spinal Column

Another term for the vertebral column, consisting of 33 bones called vertebrae.