1.1 -- bones (parts / processes) Flashcards
how does the skeletal system assist with protection in the body ?
- the bone marrow produces blood, including the white blood cells that are part of the immune system
- bones also protect internal organs (heart, lungs, brain) from damage
compact bone
forms the outside of bones & most of the diaphysis (“nature of being across” shaft), osteons are close together
spongy bone
found inside short, flat, & irregular bones & in the epiphyseas (“nature of being on top” ends) of long bones
how does the overall structure of bone provide great strength & flexibility, but keep bone from being too bulky & heavy ?
- bone is stronger than concrete (pound for pound) & stronger than any other natural material
- cells are hollow & have paper-thin walls, giving bone its lightweight structure
- calcium & phosphorus give bone its rigid strength, but ~1/2 of bone mass is soft & alive, allowing bones flexibility to bend
- every bone cell is replaced every 7 years, keeping bone strong
what is an x-ray ?
- an invisible type of high energy radiation
- soft tissues are made of smaller atoms & don’t absorb x-ray photons well
- the calicum atoms in bone are larger & absorb x-rays better
- that causes a picture of the bones to show up
what are the different types of bone fractures & how are they identified on x-ray ?
communited, transverse, greenstick, depression, oblique, open, compression, closed, spiral
comminuted
break in several pieces, splintered/crushed
transverse
complete break at right angle to bone axis, often from direct blow
greenstick
imcomplete, bone is bent & partially broken, most common form in kids
depression fracture
fragment is pushed down, typically due to a blow to the skull
oblique fracture
break has curved/sloped pattern, often caused by slanted blow
open
bone breaks through skin – greater risk of infection
compression
collapse of vertebra, often due to osteoporosis (“holes in bones”) or tumors or to being ejected from an ejection seat
spiral
caused by twisting force on bone, such as rotation to leg during skiing
closed
bone breaks, but doesn’t puncture skin
how can damage to a bone affect other human body systems ?
- fat tissue from the bone marrow can leak into the blood, causing fat embolism syndrome, which can cause lung problems & seizures
- if the skin breaks (open fracture), pathogens can enter the body & cause an infection
what is bone remodeling ?
- bone remodeling happens throoughout life & is also called “bone metabolism”
- it’s the process by which bone tissue (ossification)
- it increases after a fracture & is the method by which the bone heals
- remodeling is rapid early in life (100% replacement during first year of life) & then slows (10% yearly for adult)
- an inbalance in the process can lead to bone diseases like osteoporosis
how do osteoblasts & osteoclasts assist with bone remodeling & overall bone homeostasis ?
- osteoblasts form new bone tissue, to replace those reabsorbed by osteoclasts – produce the organic part of bone (osteoid), made mostly of collagen protein, that inorganic minerals crystalize around – many of them turn into mature osteocytes
- osteoclasts break down & reabsorb bone tissue – come from monocytes in bone marrow, release minerals (calcium phosphate) & other stored materials (like growth factors)
what is the relationship between bone remodeling & blood calcium levels ? how do hormones assist in the maintenance of healthly bone & the release of calcium to be used in other body processes ?
low blood calcium
- glands in the parathyroid release parathyroid (PTH), causing osteoclasts to break down matrix & release calcium ions into blood
high blood calcium
- c cells in the throid release calcitonin & that stimulates storage of calcium in bones
