Skeletal System Flashcards
Skeleton


Cranium (10)


Facial Bones (10)

Holes - Mental
Foramen: holes in skull where nerve tissue pass through

Nasal Cavity (3)

There are sinuses.

Infant Skull

Closes after 18 months

Bone structure

Type of connective tissue composed of calcium phosphate(Ca3 (PO4)2)
- Proximal ephiphysis: have articular cartilage
- Diaphysis: Longest part of the bone shaft
- Distal epiphysis: have articular cartilage
- Epiphseal line/plate: made of articular cartilage when it is growth plate –> hardens when you grow older
- Periosteum: tissue that coats outside live bone, preforated
- Medullary caity (lined by endosteum): where bone marrow exists
- Bone ossifies = hardens
- Hyaline cartilage: covers articular surface of epiphysis; provides smooth surface that reduces friction at joint surfaces
- Epiphyses: ends of long bone, each has a thin layer of compact bone and central area of spongy bone; in adults, red marrow, which forms blood cells, is confined to these cavities in the spongy bone of some flate bone and epiphyses

Compact Bone
solid matrix of organic substances and inorganic salts such as calcium phosphate
- Matured bone is layered → lamellar: concentric layers
- Around vascular canals called haversian canals, which contain blood vessels which give nutrients to the osteon
- Immature bones do not have osteons → just a woven mesh of overlapping collagen fibers → makes kids more flexible
- The older you are, the more lamellar the bone gets
- 80% of bone → compact bone; 20% → spongy

Cancellous Bone/Spongy Bone
- Trabeculae (lattice) of spongy bone
- Spaces are filled with bone marrow
- less dense structure and higher surface area than dense bone
- large irregular spaces containing red bone marrow
Cartilage
(found in ears, vertebrae, between pubic symphysis)
- Made by cells called chondroblasts which form →
- Chondrocytes (the actual cells) which form→
- Collagen and elastin fibers (provide flexibility)
Vertebrae
column of irregular bones
Three sections:
- cervical
- thoracic
- lumbar

Thoracic Cage

- True ribs: go from your back and attach to sternum through costal cartilage
- False ribs: do not connect directly to sternum. Their cartilage connects them to one another and the cartilage connects to the sternum
- Floating ribs: only attach at spinal cord
- Clavicle attaches to sternum at the manubrium

Osteoprogenitor
form bone tissue (make → osteoblasts)
Osteoblasts
majority of your bone (make → osteocytes)
Osteocytes
- Maintain bone tissue (make → osteoclasts)
- embedded in a lacuna within the matrix
- mature bone cell
Osteoclasts
reabsorb bone material for development and repair
Bone Function
- Support/locomotion, structure, mineral storage, calcium storage, blood production
- support and protect soft tissues and organs
- enable movement by providing attachment for muscles
*
Types of bones
- Short - wrist, ankle, patella
- cube shaped and contain mostly spongy bone
- Strength upon impact, compactness, shock absorption
- Long - limbs
- Support, locomotion, levers (weight distribution)
- Flat - skull, shoulder blade, ribs
- Protection, muscle attachment
- Irregular
- vertbrae, hip bones, facial bones
Cervical vertebrae
- the “neck” which contains the first 7 vertebrae
- C-1 + C-2 form atlas and axis (pivot joint in your head that allow you to turn head)
- Process on axis is called dens (it allows rotation)
- C-2 + C-5 are forked for muscle attachment
- smallest and lightest of the vertebrae
- always have openings (foramina) through which the vertebral arteries pass

Thoracic vertebrae
- larger than the cervical vertebrae, with a slightly heart shaped body
- transverse processes articulate with the ribs
- spinous process is long and points sharply downward

Lumbar vertebrae

- contains larger bones to support more weight
- large block-like body and short processes

Bone Fractures
- Compound: breaks through two different tissues (ex: through bone and skin)
- Transverse: crack, clean break, could offset the bone
- Greenstick: not completely cut through, on one side → happens in young bones because the bone hasn’t completely ossified
- Spiral: crack happens at angle and spirals down, twisting
- Comminuted: when the bone breaks into several pieces
- Stress: hairline crack
- Vertebral compression: when vertebrae compress because of weight

Bone Repair Steps
- Reactive Phase
- Inflammatory
- Granulation
- Reparative Phase
- Cartilage callus formation
- Lamellar bone deposition
- Remodeling Phase
Reactive Phase
1
happens immediately in the first 6-8 hours of injury
- Inflammatory - the bone bleeds out, forms a bruise (hematoma), blood cells clot and die if close to injury
- Granulation - fibroblasts that survive replicate and form granules, blood supply to the break is cut off
Reparative Phase
2
4-6 weeks after injury → break is immobilized (by the doctor)
- Cartilage callus formation - cells of periosteum replicate and transform, they develop chondroblasts, chondroblasts make cartilage that connects the two breaks
- Distal cells form osteoblasts which form woven bone and aggregate to form fracture callus
- Lamellar bone deposition - ossification of cartilage callus
- Fracture callus is mineralized
- Mineralized matrix become perforated with microvessels
- Osteoblasts populate the site and lay down trabecular bone-
- Trabecular bone replaces the fracture callus (which was softer)















