Cartilage/Bone Flashcards
what 2 compounds help retain water?
1) proteoglycans
2) glycoproteins
what does collagen provide to cartilage?
- flexibility
- resiliency
- diffusion thru the membrane
- tensile strength
what do elastic fibers help collagen to do?
regain original shape
what are the 2 types of cartilage growth?
1) appositional
2) interstitial
what is appositional cartilage growth?
new cartilage forms at the surface of existing cartilage (so cartilage grows from outer edges)
what is interstitial cartilage growth?
when new cartilage forms WITHIN existing cartilage
what are the 3 types of cartilage?
1) fibrocartilage
2) elastic cartilage
3) hyaline cartilage
what are some characteristics of fibrocartilage?
- has visible fibers; NO perichondrium
- associated with dense regular CT
- more collagen fibers
where is fibrocartilage found in?
- tendon-bone junction
- intervertebral discs
- menisci (knee)
what cell types make collagen?
- fibroblasts
- reticular cell
- smooth muscle cells
- epithelial cells
- osteoblasts (bone)
- chondroblasts (cartilage)
why is there a lacuna around chondrocytes?
matrix is more rigid than other types of CT, so matrix is retained upon fixation, but cell shrink a little (leaving an empty space around them)
what is a chondrocyte?
a chondroblast that is fully surrounded by matrix
describe characteristics of hyaline cartilage
- glassy appearance
- perichondrium
- high proteoglycan content & water content (gives glassy appearance)
where is hyaline cartilage found?
- fetal skeletal tissue
- epiphyseal plates
- articular surface (no perichondrium)
- respiratory system
describe some characteristics of elastic cartilage
- elastic stain
- perichondrium
- often continuous w/ hyaline cartilage
where is elastic cartilage found?
- ear (pinna, meatus, tube)
- epiglottis/larynx
what is the difference between dense regular CT and fibrocartilage visually?
- fibrocartilage has lacuna around cells
- dense regular CT contains fibrocytes with no lacuna
what are the 3 parts of a long bone?
1) epiphysis
2) metaphysis
3) diaphysis
what is the structure and function of bone?
- structural = protection of internal organs; mechanical movement with skeletal muscle
- metabolic = hematopoiesis; calcium/phosphate storage
what are osteoprogenitor cells?
- line marrow cavity
- differentiate into osteoblasts
- are not distinctive histologically
what are bone-lining cells?
- inactive osteoblasts
- cover static bone where bone is not being laid down
what are osteoblasts?
- line marrow cavity
- deposit (BUILD) matrix
- also found in periosteum
what are osteocytes?
- mature bone cell
- maintain matrix (SIT)
- surrounded by matrix
what are osteoclasts?
- phagocytic bone cell (CLEAVE)
- bone reabsorption
- breaks down bone to release calcium & phosphate
what do parathyroid hormone & calcitonin do in bone?
- parathyroid hormone = inhibits osteoblasts to reduce bone matrix production; reduced bone matrix production means more calcium available in blood, less calcium for bone
- calcitonin = inhibits osteoclasts to slow bone resorption; DECREASES blood calcium
where is calcitonin produced?
in thymus gland
what are the steps in bone mineralization?
1) increase local calcium & phosphate concentrations
2) secretion of vesicles that accumulate additional calcium & phosphate
3) increase in local isoelectric point crystallizes calcium phosphate
4) additional crystallization into hydroxyapatite crystals (initial deposit is called osteoid)
what are the 2 methods of bone formation?
1) intramembranous ossification (initial development)
2) endochondral ossification (growth plates/epiphyseal plates)
what are the steps of endochondral ossification?
1) proliferation
2) hypertrophy
3) calcification
4) reabsorption of cartilage
what are the steps in bone remodeling?
1) osteoclasts (CLEAVE) bore through tissue
2) osteoblasts (BUILD) lay down new matrix
3) lamellar reach minimum circumference
4) Haversian canal is lined by bone-lining cells (endosteal cells)
what are the 2 types of synoviocytes?
1) phagocytic = digests debris in synovial fluid
2) productive = makes synovial fluid
what is synovial fluid and what does it do?
- contains hyaluronan for cushioning, lubricin for lubrication, nutrients
- function: cushioning impact, lubrication of articular cartilage, support of articular cartilage
what is the healing process of a broken bone?
1) blood clot forms in area of break due to blood vessels in Haversian canals
2) space will be filled up with fibrocartilage along w/ loose CT with a lot of immune cells (macrophages to clean up debris) = new blood vessels forming
3) converted to spongy bone
4) new compact bone will form thru remodeling
