Chapter 7: Bones & Bone Tissue Flashcards
bone functions
- shape
- support
- protection
- movement
- electrolyte balance
- blood production
- acid-base balance
shape
bones give the body its structure
support
the bones of the legs, pelvis, and vertebral column support the body and hold it upright
protection
bones protect delicate internal organs (heart, lungs, brain, spinal cord, etc)
movement
the interaction between muscles and bones gives us the ability to move our arms and legs and breath
electrolyte balance
bones store and release minerals (ie calcium & phosphorus) necessary for chemical reactions throughout the body
blood production
bones encase blood marrow, a major site of blood cell formation
acid-base balance
bone absorbs and releases alkaline salts to help maintain a stable pH
strength
bone is as strong as steel and as light as aluminum
long bones
- long axis
- longer than they are wide
- work like levers to move limbs
- ex. femur, humerus
short bones
- about as broad as they are long
- tend to be shaped like cubes
- ex. carpal bones (wrist) and tarsal bones (ankle)
flat bones
- thin, flat, often curved
- protect organs
- skull, ribs, breastbone
- some provide large surface area for attachment of muscles (like shoulder blades)
irregular bones
- often clustered in groups
- various sized and shapes
- ex. vertebrae and facial bones
epiphysis
- the head of each end of a long bone
- its bulbous structure strengthens the joint
- allows an expanded area for the attachment of tendons and ligaments
- made of porous-looking spongy bone
diaphysis
- the central shaft-like portion of the bone
- a hollow cylinder
- made up of thick, compact bone
- strong enough to support a large amount of weight
articular cartilage
- covers the surface of the epiphysis
- thin layer of hyaline cartilage
- this cartilage (along with a lubricating fluid) eases the movement of the bone within a joint
medullary cavity
the central hollow portion of a bone
endosteum
a thin epithelial membrane that lines the inside of the medullary cavity
periosteum
- a dense, fibrous membrane that covers the diaphysis
- some fibers penetrate the bone, making sure the membrane stays firmly anchored
- other fibers weave together with the fibers of tendons
- ensures a strong connection between muscle and bone
- contains bone-forming cells and blood vessels
- crucial for bone survival
epiphyseal plate
- present in growing children
- aka “growth plate”
- a layer of cartilage that separates the epiphysis and the diaphysis at each end of a long bone
- replaced by an epiphyseal line once growth stops
osteomyelitis
- an inflammation of bone and marrow
- usually the result of a bacterial infection
- bone infections are difficult to treat and usually require prolonged IV antibiotics
osteoblasts
help form bone by secreting substances that comprise the bone’s matrix
osteoclasts
dissolve unwanted or unhealthy bone
osteocytes
- mature osteoblasts
- have become entrapped in the hardened bone matrix
- have a dual role
- some dissolve bone
- some deposit new bone
- contribute to the maintenance of bone density
- assist with the regulation of blood levels of calcium and phosphate
bone composition
- bone is osseous tissue
- consists of cells, collagen fibers, and crystalline salts (primarily calcium and phosphate)
- hard and calcified
- bone cells include osteoblasts, osteoclasts, and osteocytes
tensile strength
- bone’s resistance to stretching forces
- due to collagen fibers in the matrix
compressional strength
- bone’s resistance to squeezing forces
- due to calcium salts
torsional strength
- bone lacks the ability to resist twisting
- most fractures occur when torsional forces are exerted on an arm or leg
weight-bearing exercise
- when bone experiences an increase in load, osteocytes trigger the growth of new bone
- makes bones stronger
- lifting weights is ideal for those at risk for osteoporosis