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49 Cards in this Set
- Front
- Back
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what are the functions of the skeletal system? |
support protection movement storage (Ca and P, fat) blood cell production |
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characteristics of cartilage |
non-vascular CT few cells and lots of matrix matrix is mostly water primary protein is collagen contains proteoglycans that trap water |
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what are the 3 types of cartilage? |
hyaline elastic fibrocartilage |
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characteristics of hyaline cartilage |
found in moveable joints
most abundant creates fetal skeletons contains mostly collagen |
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characteristics of elastic cartilage
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main protein is elastin
more flexible |
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characteristics of fibrocartilage |
strongest found in interveterbral discs does not contain perichondrium |
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what is a chondrocyte? where is it located? |
mature cartilage cell lacunae |
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what is a chondroblast? what is its role? |
immature chondrocyte secrete matrix around themselves and then turn into chondrocytes |
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what is the perichondrium? what are the 2 layers of the perchondrium? |
- CT that covers cartilage - inner layer contains chondroblasts - outer layer contains fibroblasts that create collagen and nerve and blood supply |
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characteristics of articular cartilage |
special type of hylaine cartilage do not contain perichondrium (no blood/nutrient supply or chondroblast layer) |
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how does appositional growth occur? |
chondroblasts secrete matrix, get trapped and become mature chondrocytes |
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how does interstitial growth occur? |
chondrocytes divide into 2 cells which then secrete matrix and move away from each other
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which type of cartilage growth occurs early in life/late in life? |
interstitial growth occurs early in life appositional growth occurs later in life |
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what is the role of osteoblasts? |
build ECM |
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what is bone ECM made of? |
inorganics - hydroxyapatite - for strength organics - collagen and proteoglycans - gives it flexibility |
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how are osteoblasts connected to each other? |
via connecting cell processes |
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how do osteoblasts make ECM? |
- organic parts are packaged into vesicles and secreted by exocytosis - Ca and P accumulates and buds off the PM as hydroxyapatite |
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what are osteochondral progenitor cells? |
stem cells found on the inner layer of the perichondrium that can become osteoblast or chondroblast cells |
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what kind of growth occurs in bone? |
appositional growth only b/c it is too rigid for interstitial growth |
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how are osteocytes connected? |
via canaliculi |
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where are osteocytes found? |
inside lacunae (cavity) |
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where are osteoclasts found? what do they do? |
on the surface of bone in the periosteum and endosteum they break down/remodel bone |
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how are osteoclasts formed? |
fusion of monocytes creates large multi-nuclear cells |
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how do osteoclasts break down bone? |
when activated, they attach to bone using podosomes and create a cavity with a ruffled border contacting the bone cell acid and enzymes are released to break down inorganic/organic portions of bone |
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what is woven bone? |
bone in which collagen fibers are randomly oriented present in fetal development, but is remodelled and turned into lamellar bone |
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what is lamellar bone? |
mature bone in which the collagen is organized into sheets/lamellae |
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what are the 2 types of lamellar bone? |
- spongy/cancellous/trabecular bone - compact/cortical bone |
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characteristics of spongy bone |
- less matrix; appears porous - sheets of lamellae are present in concentric rings - found inside bones, the ends of long bones, and flat/short/irregular bones |
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what are trabeculae? |
regions of bone oriented along lines of stress that create a porous appearance in spongy bone each trabecula is surrounded by a layer of osteoblasts and osteoclasts |
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characteristics of compact bone |
- dense bone w/ few spaces - typically found on the outside of bones or in the shaft of long bones |
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what are central/haversian canals? |
blood vessels running through the long axis of a compact bone |
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what are the 3 orientations of lamellae in compact bone? |
1. concentric lamellae - surround central canals 2. circumferential lamellae - surround the outside of bone 3. interstitial lamellae - b/w osteons and b/w osteons and circumferential lamellae |
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what is an osteon? what is it also called? |
concentric lamellae surrounding a central canal aka haversion system |
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what are the canals that run perpendicular to other blood vessels in compact bone called? |
perforating/Volkmann canals |
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what is a diaphysis? |
- shaft region of a long bone made of compact bone with a thin layer of spongy bone |
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what is the cavity inside the diaphysis called? what is it filled with? |
medullary cavity bone marrow |
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what is an epiphysis? |
the end of a long bone, made mostly of spongy bone, but has a layer of compact bone a long bone can have more than one, allowing it to grow in different directions |
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what is the region b/w the epiphysis and diaphysis called? what is it made of? |
epiphyseal plate hyaline cartilage until it ossifies with age |
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what is the periosteum? |
CT layer on the outside surface of all bones |
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what is the endosteum? |
the CT layer on the inside surface of bone that wraps around trabeculae contains osteoprogenitor, osteoclast and osteoblast cells |
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what are the 2 layers of the periosteum? |
inner layer - contains osteoprogenitor, osteoblast and osteoclast cells outer layer - dense CT containing blood vessels and nerves |
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where are compact and spongy bone present in adult bones? |
spongy bone is present in a thin layer inside the medullary cavity compact bone is present in the rest of the diaphysis |
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what layers allow for bone remodelling? |
endosteum and the inner layer of periosteum |
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characteristics of flat bones |
- layer of spongy bone b/w compact bone - no diaphysis or epiphysis |
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characteristics of short/irregular bones |
cancellous bone surrounding compact bone no diaphysis or epiphysis |
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what are mesenchyme cells? |
stem cells that can differentiate into all CT some become osteoprogenitor cells |
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what are the 2 ways to form bone? |
intramembranous ossification - mesenchyme cells create a network of CT that is turned into bone by osteoblasts endochondral ossification - cartilage is built first, and then turned into bone |
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how does bone growth in length occur? |
1. zone of resting cartilage that is slowly dividing 2. zone of proliferation - chondrocytes are rapidly dividing through interstitial growth 3. zone of hypertrophy - chondrocytes enlarge, mature and calcify 4. zone of calcification - cartilage is calcified and osteoblasts are present 5. ossified bone |
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how does bone growth in width occur? |
1. osteoblasts beneath periosteum lay down bone to form ridges 2. when ridges meet the periosteum pinches 3. osteoblasts form new concentric lamellae and osteons |
