뒤로bone part 4
이 집합의 용어 (34)
bone resorption
osteoclasts secrete hydrogen ions and enzymes from their ruffled borders onto the bone ECM
what do hydrogen ions do in bone resorption
make the pH more acidic, breakd down hydroxyapatite crrystals in onorganic matrix
what do enzymes do in bone resorption
catalyze reactions that break down proteoglycans, glycosaminoglycan, glycoproteins then taken into osteoclasts for later use
bone remodeling response to tension and stress
the heavier the load a bone carries the more bone tissue deposited in that bone
compression
act of pressing together, stimulates bone deposition
tension
stretching force, stimulates bone deposition
pressure
application of continuous downward force, stimulates bone resorption
what does testosterone promote
bone deposition
what does estrogen depress
osteoclast activity
calcium ion intake
required for bone deposition
vitamin d intake
promotes calcium ion absorption and prevents calcium loss in urine
vitamin K intake
required for osteocalcin to bind calcium ions, promotes proliferation of osteoblasts
what is viamin c required for
synthesis of collagen
protein intake
needed for osteoblasts to synthesize collagen fibers needed for organic matrix
parathyroid hormone
stimulates effects that increase blood calcium levels, produced in parathyroid glands
calcitonin
stimulates effects that decrease blood calcium levels, produced in thyroid gland
increasing blood calcium level stimulus
blood calcium ion level decreses below normal range
receptor
parathyroid gland cells detect low blood calcium ion level
control center
parathyroid gland cells increase their release of PTH into the blood
effector
PTH stimulates effects that increase the blood calcium ion level
step 1 of fracture healing
hematoma fills the gap between the bone fragments
step 2 of fracture healing
fibroblasts and chondroblasts infiltrate the hematoma , soft callus forms
step 3 of fracture healing
osteoblasts build a bone callus
step 4 of fracture healing
bone callus is remodeled and primary bone is replaced with secondary bone
simple fractures
skin and surrounding tissue remains intact
compound fracture
damage around the fracture
treatment of fractures
stabilization of the fracture, immobilization for 6 weeks
closed reduction
bone ends are brought into contact
open reduction
fracture is surgically fixated with plates, wires, or screws
spiral fracture
twisting forces applied to bone
compression fracture
bone is crushed under weight
comminuted
bone is shattered into multiple fragments
avulsion fracture
tendon or ligament pulls fo of fragment of bone
green stick
bone breaks on one side