The Skeletal System Flashcards
AXIAL SKELETON
80 fused bones giving limited motion
- Cranium (22)
- Auditory ossicles (6)
- Hyoid bone (1)
- Vertebral column (26)
- Ribs (24)
- Sternum (1)
APPENDICULAR SKELETON
126 unfused bones allowing motion
- Pectoral girdles (4)
- Arm and forearm (6) * Hands (54)
- Pelvis (2)
- Thigh and leg (8)
- Feet (52)
Long Bones
Bones whose length exceeds their width
Function
* Leverage
* Blood cell production
Examples
* Femur, humerus
Short Bones
Bones with equal length and width
Function
* Weight bearing
Examples
* Tarsals, carpals
Flat bones
Thin bones that tend to be curved rather than flat
Function
* Protection
Examples
* Cranium, sternum
Irregular Bones
Bones that do not fit into the other three categories
Function
* Individualised
Examples
* Vertebrae, sacrum
Functions of the skeleton
- Protection
- Support
- Movement
- Blood production
- Storage
- Shape
Protection
- Protects the vital organs
Support
- Soft tissues supported by the skeleton
Movement
- Comprised of numerous joints which allow movement through leverage
- Occurs due to muscles pulling on bones via tendons
Blood Production
- Red and white blood cells are formed in the marrow cavities of some long bones
- Controlled by the hormone erythropoietin (EPO)
Storage
- Bones store numerous minerals such as calcium, phosphorous, potassium and sodium
- Storage occurs mostly in long bones
Shape
- The skeleton gives the body its shape * Body shape genetically determined
Cortical Bones
- Also known as compact bone
- Very dense and hard
- Formed for protection and structure
Cancellous Bones
- Also know as spongy bone
- Lighter and less dense than cortical bone
- Contains bone marrow
Epiphysis
- The area at each end of a long bone.
- Made mostly of cartilage in childhood which hardens to become cancellous (spongy) bone in adulthood.
- Contains red marrow.
Diaphysis
The central shaft of a long bone made of cortical (compact) bone.
Periosteum
- A thin fibrous membrane which covers the surface of bone.
- It contains blood vessels which supply nutrients and nerves which signal pain.
Epiphyseal Disks Lines
- Lie between the epiphysis and the diaphysis.
- Growth area where cartilage cells form columns
- Push older cells towards the middle of the bone shaft.
Medullary Cavity
- A hollow or canal inside the shaft of the bone
- Contains red marrow used to produce blood cells
- Contains yellow marrow which is a store for fat.
Articular Cartilage
- Forms a smooth, white, shiny mass on the surface that looks like marble.
- Protects the bone tissue and helps to reduce friction between the bones.
