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75 Cards in this Set
- Front
- Back
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what are the five functions of the skeletal system?
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1. support- structural framework for soft tissue (organs, muscles)
2. storage of minerals and lipids- break our bones down continuously all day long and get minerals from it 3. blood cell production- RBC, WBC, and platelets are produced in red bone marrow 4. protection- tissues and organs are protected (ribs, skull, vertebrae, pelvis) 5. leverage- can move with the muscles attached |
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what is hemopoiesis?
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RBC production in red bone marrow
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what are the two types of bone markings?
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1. tension creates raised areas called: processes, heads, condyles, tuberosities, and facets
2. compression creates holes and depressions called: fissures, foramens, and fossa |
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what types of bone markings does tension create?
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processes, heads, condyles, tuberosities, and facets
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what types of bone markings does compression create?
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holes and depressions called: fissures, foramens, and fossa
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what are the two types of bone textures?
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compact and spongy
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what is a compact bone?
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the outer dense layer
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what is a spongy bone?
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-its the same thing as a compact bone but forms differently because of how the matrix is laid down
-reduces weight of skeleton making it easier for muscles to move the bones -bone marrow |
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where is spongy bone located?
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the inner trabeculae; where bones arent heavily stressed or where stresses arrive
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what is the bone marrow in spongy bone like?
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-in adults we have red bone marrow in flat and irregular bones
-yellow bone marrow (fat) in long bone shafts -bone marrow makes bones lighter |
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what is red bone marrow?
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highly vascular and involves in the production of blood cells
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what is yellow bone marrow?
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adipose tissue important to the storage of energy resevres; fat
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what three things does the long bone structure consists of?
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1. diaphysis
2. epiphyses 3. membranes |
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what is the diaphysis?
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shaft (body) of the long bone
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what is the epiphyses?
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at each end of the bone; before fully grown you will have an epiphyical plate (growth plate)
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where are the membranes in the long bone?
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between the diaphysis and epiphyses- the growth plate
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what are the two types of membranes of the long bone?
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1. periosteum
2. endosteum |
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what is the periosteum?
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surrounds/hovers all the bones; contains extensive network of blood vessels (supply superficial osteons), lymphatic vessels (collect lymph from branches that enter the bone and reach osteons), and sensory nerves (travel with the branches of the nutrient arteries)
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what is the endosteum?
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its the membrane that lines the bones and is located within the bone cavities; it only has a single, osteogenic layer
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what layers does the periosteum consist of?
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-fibrous outer layer
-osteogenic inner layer |
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what does the osteogenic inner layer of the periosteum consist of?
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osteoprogenitor cells, osteoblast cells, and osteoclast cells
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what are osteoprogenitor cells?
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stem cells from the mesentyme tissue that wind up differentiating to osteoblasts
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what are osteoblast cells?
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initiate calcification; they perform bone building; synthesize and secrete bone matrix; the matrix contains collagen fibers and ground substance
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what is osteogenesis?
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bone building
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what did osteoblasts originate from?
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osteoprogenitor cells
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what happens when osteoblasts become trapped in the matrix?
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they mature
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what are osteoclast cells?
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-they break bone down so we can repair and put calcium into our bones
-they're giant cells |
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what is osteolysis?
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breakdown of bone
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how much nuclei do osteoclats have?
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up to 50
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how do osteoclasts breakdown bones?
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by using lysosomal enzymes and acids
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what is the periosteum's main functions?
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-provides route for nerves, blood, and lymph to keep the cells alive through diffusion
-anchoring point for tendons and ligaments |
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what makes up the marrow cavities?
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red bone marrow and yellow bone marrow
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what is red bone marrow and where is it found?
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it is in the hematopoietic cavity; its found in adults in flat bones, the end of long bones, and irregular bones; the blood is going through all the bone
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what is the yellow bone marrow and where is it found?
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adipose tissue; as we age we lose the red bone marrow and by age 21, 76% of it has turned yellow; fat tissue
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what seven things is compact bone consisted of?
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-osteon
-lamellae -lacunae -canaliculi -blood vessels, lymphatic vessels -interstitial lamellae -circumferential lamellae |
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what are osteons?
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(haversian system) structural unit (this is the functional unit)
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what do osteons consist of?
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consists of rings of mineral deposits (concentric rings of bone) called lamellae
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what are lamellae?
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rings of mineral deposits(concentric rings of bone)
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what do lamellae consist of and where is in?
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in the matrix; consists of collagen fibers and crystal salts
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how much of the bone are collagen fibers?
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1/3 of the bone
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how much of the bone consists of crystal salts?
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2/3 of the bone
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what does each lacunae contain?
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one osteocyte because osteocytes cannot divide
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how are lacunaes connected together?
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by canals called canaliculi and lead to a central canal
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what are osteocytes?
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mature bone cells that reside in the lacunae that maintain daily metabolism of bone and maintain the matrix
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what is a possible cause of the formation of gap junctions between neighboring cells?
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cytoplasmic extensions into canaliculi towards neighboring canals and osteocytes
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what are canaliculi?
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they connect lacunae to lacunae and lead to the central canal
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why do we have canals?
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to get nutrients
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what canals are contained in the blood vessels, lymphatic vessels, and nerves?
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haversian canals and volkmann's canals
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where are haversian canals?
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in the center of the osteon; verticle (run parallel in with cone)
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where are volkmann's canals?
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perpendicular to the haversian canals
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what connects the haversian canals?
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the volksman canals
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where is the interstitial lamellae?
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areas of osteon fragments (partially destroyed older osteons)
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what is circumferential lamellae?
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formed during development of the bone
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what three things is the bone tissue composed of?
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1. organic components
2. inorganic components 3. fibers and crystals |
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what do organic components do to bone composition and what is it made of?
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its what makes the bone hard and it is made up of osteoids
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what are osteoids made up of?
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ground substance and collagen fibers
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what are the inorganic components in bone tissue?
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-65% by mass
-crystals of hydroxyapatite -majority is made of calcium components |
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what are the components of calcium?
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-major form is calcium phosphate which interacts with calcium hydroxide to form hydroxyapatite
-also include calcium carbonate: Na+, Magnesium, fluoride |
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what are the three mechanisms of bone growth?
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1. intramembranous ossification
2. endochondral ossification 3. appositional ossification |
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what is the mechanism of intramembranous ossification?
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-formed within a membrane and a sheet of CT
-involves cartilage and occurs during development to form bone |
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when does intramembranous ossification begin?
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5 weeks of life?
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what is the mechanism of endochondral ossification?
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formation within a cartilage model and occurs during development and through adolescence
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what is the mechanism of appositional ossification?
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-formation of new bone along bone surface and is done after development
-growth as we grow to an adolescent |
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what does intramembranous ossification form?
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bone within fibrous membranes and dermal bones
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what dermal bonesare produced during intramembranous ossification?
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skull, mandible, and the clavicle
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where does intramembranous ossification begin?
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at the ossification center which is the area in the membrane where a chemical message initiates bone formation
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what are the three steps of intramembranous ossification?
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1. mesenchymal cells cluster to differentiate into osteoblasts (bone forming cells) and lay down the matrix which begins calcification of the membrane
2. blood vessels grow into the trabeculae and become trapped 3. remodeling takes place and contructs final structure of bone (form, size, shape, etc.) |
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what are osteoblasts?
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bone forming cells
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what are trabeculae?
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they are columns of spongy bone where blood vessels get trapped and become bone marrow
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what happens to the connective tissue of the blood vessels during intramembranous ossification?
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it differentiated into bone marrow
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what does appositional growth form?
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forms bone along bone surface for strength, usually compact bone is added
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what are the three components of appositional growth?
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1. periosteum osteoblasts secrete bone matrix to the outside
2. endosteum osteoclasts remove bone 3. unequal process produces strong bones but prevents bones from being too heavy |
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where is endosteum located?
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on the inside of the bone
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what do you need to have present in order to add bone to the surface of bone?
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blood vessels
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what do osteoblasts produce and assist in during ossification?
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it produces new bone matrix and assis in elevating local concentrations of calcium phosphate
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