SKELETAL SYSTEM UNIT 6 Flashcards
Parts of the skeletal system:
Bones, Joints, Cartilages, Ligaments
Ligaments connect..
Bone to bone
Tendons connect….
Muscle to bone
Functions of the bone:
- Support the body
- Protection of soft organs
- Movement due to attached skeletal muscles.
- Storage of minerals
- Blood cell formation
2 minerals bone store…
Calcium & Phosphorus
What is compact bone?
- Forms the outer layer of bone and makes up the shaft of long bones.
- 75-80% of the skeleton
- Dense bone/heavy
What is spongy or cancellous bone?
- Has many open spaces
- Found at the end of long bones and the middle of other bone types.
- Small needle-like pieces of bone called trabeculae.
How is trabeculae form?
Formed due to stresses and gives bone strength.
How many bones does the human body have?
206 bones
2 divisions of the skeleton are:
Axial & Appendicular Skeleton
Axial Skeleton:
- Found in the head and torso
- Skull, spine, ribcage
Total bones in the axial skeleton?
80 Bones
Appendicular Skeleton:
- Found in the appendages/limbs
- Arms, legs, pelvis, and shoulders
Total bones in appendicular skeleton?
126 Bones
Different types of bone shape:
Long, Short, Irregular, Flat, & Sesamoid Bones
Long Bones:
- Longer than wide
- Have a shaft with heads at both ends
- Contain mostly compact bone
Examples of long bones?
Femur & Humerus
Short Bones:
- Generally cube-shaped
- Contain mostly spongy bone
Examples of short bones?
Carpals & Tarsals
Flat Bones:
- Thin and flattened
- Usually curved
- Thin layers of compact bone around a layer of spongy bone
Examples of flat bones?
Skull, ribs, & sternum
Irregular Bones:
- Irregular shape
- Don’t fit into other bone classification categories
Examples of irregular bones?
Vertebrae & hip
Sesamoid Bone:
- Small independent bone developed in a tendon where it passes over an angular structure.
Examples of sesamoid bones?
Patella
Osteon…
- Unit of bone
- Consists of a central canal which is surrounded by concentric rings.
Harvesian Canal…
- Opening in the center of an osteon-central canal.
- Carries blood vessels and nerves
Volkmann’s Canal….
- Canal perpendicular to the central canal.
- Carries blood vessels and nerves
Lamallae…
- Rings around the central canal
- Sites of lacunae
Lacunae….
- Cavities containing bone cells
- Arranged in concentric rings between the lamallae
Canaliculi…
- Tiny canals between lacunae
- Radiate from the central canal to lacunae
- Form a transport system to deliver nutrients
Osteocytes
Bone cells
Osteoblasts
Cells that form the matrix, form new bone
Osteoclasts
Break down the bone whether it is old bone, remodeling bone, or body CA++.
Osteoprogenitor Cell
Stem cells in the bone, only bone cells that divide, can differentiate into other types of cells.
Diaphysis…
- Shaft (middle)
- Composed of compact bone
Epiphysis..
- Ends of the bones
- Lined with compact bone. Composed mostly of spongy bone
Periosteum….
- Outside covering of the diaphysis
- Fibrous connective tissue memebrane
Sharpey’s Fibers…..
- Secure periosteum to underlying tissue
Arteries…
- Supply bone cells with nutrients
Articular cartilage….
- covers the external surface of the epiphysis
- made of hyaline cartilage
- decreases friction at joint surfaces
Epiphyseal Plate….
- Is a plate of hyaline cartilage found in children and adolescents, allows for growth
Epiphyseal Line….
- Replaced by a line in adults when growth has stopped
Site of hematopoesis?
- Red bone marrow
Medullary Cavity..
- Cavity of the shaft
- Contains yellow marrow (mostly fats) in adults
Endosteoum…..
- A thin vascular membrane that lines the inner surface of the medullary cavity
Bone Markings:
- Surface features of bones
- Sites of attachments for tendons, & ligaments
- Passages for nerves and blood vessels
Projections and Processes
Grow out from the bone surface
Depressions or Cavities
Indentations, holes
The axial skeleton forms…
The central axis of the skeleton
Axial skeleton is divided 3 parts…
Skull, Vertebral Column, & Bony thorax
Function of the axial skeleton?
Protection
Cranial bones are
Parietal (2), Temporal (2). Frontal (1), Occipital (1), Ethmoid (1), & Sphenoid (1)
Facial Bones are
Maxilla (2), zygomatic (2), mandible (2), nasal (1), palatine (2), inferior nasal concha (2), lacrimal (2), & vomer (1)
