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Block 2 Histology Exam One
VCOM Block 2 2011
68
Histology
Graduate
10/22/2011

Additional Histology Flashcards

 


 

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Term
lacunae
Definition
artifact hole left during processing where chondrocytes and osteocytes were located
Term
cartilage
Definition
solid form of connective tisseu with varying degrees of solidity. develops directly from mesenchyme. avascular (so vulneralbe to degeneration).
Term
perichondrium
Definition
layer of dense connective tissue that surrounds cartilage. reserve chondroblasts are located just deep to this structure and they are flat rather than rounded cells
Term
appositional growth
Definition
formation of new cartilage at surface just beneath perichondrium
Term
interstitial growth
Definition
internal formation of new cartilage via re-conversion of lacunae bound chondrocytes to chondroblasts with the subsequent synthesis of new cartilage. this process is impeded greatly by avascular nature
Term
ground substance of cartilage
Definition
chondroitin sulfate; present in all three types
Term
hyaline cartilage
Definition
hardest and most abundant; matrix contains few collagen fibers; found in articular cartilages, tracheal rings, costal cartilages, thyroid cartilage, and nose
Term
fibrocartilage
Definition
contains more collagen fibers in matrix; provides tough support with tensile strength; located in IV discs, pubic symphysis, meniscus of knee
Term
elastic cartilage
Definition
most pliable; contains interlacing elastic fibers and collagen fibers; provides both form and flexibility; located in external ear, eustachian tubes, epiglottis, and larynx
Term
cortex
Definition
outer solid region of compact bone; deposited in layers called lamellae
Term
spongy or cancellous bone
Definition
found in epiphyses and peripheral to medullary cavity; containes blood cell progenitors and adipose; bony spicules called trabeculae; engineered to withstand physical stress placed upon bone
Term
lamellae
Definition
layers of bone within an osteon
Term
Haversian canal
Definition
canal in center of osteon that contains blood vessels and nerves
Term
osteocytes
Definition
mature bone cells
Term
cannaliculi
Definition
cytoplasmic extensions off of lacunae that nutritionally interconnect osteocytes to vessels of haversion canals
Term
interstitial lamellae
Definition
components of previous haversion systems that are no longer obvious due to remodeling
Term
Volkman's canals
Definition
transversely connect Haversian canals
Term
decalcified preps
Definition
only way to see bone cells
Term
dry ground preparations
Definition
only way to see haversion system
Term
osteoprogenitor cells
Definition
undifferentiated fibroblast-like cells that give rise to osteoblasts; a few persist in adult bone and are located deep to periosteum
Term
osteoblasts
Definition
synthesize glycoproteins and mucopolysacharides that are secreted to form osteoid
Term
osteoid
Definition
uncalcified ground substance
Term
osteocytes
Definition
formed when osteoblasts become surrounded by matrix and therefore encased within a lacunae
Term
osteoclasts
Definition
large multinucleated cells that digest bone matrix
Term
Howship's lacunae
Definition
indentations in compact bone due to osteoclast resorption
Term
matrix
Definition
strength from highly ordered collagen fibers (osteoid) and rigidity from calcium hydroxyapatite
Term
endosteum
Definition
internal lining of simple squamous epithelia plus underlying dense irregular connective tissue
Term
periosteum
Definition
external lining of simple squamous epithelia plus underlying dense irregular connective tissue
Term
Sharpey's fibers
Definition
attach bone to periosteum
Term
intramembranous ossification
Definition
results in formation of flat bones; mesenchyme becomes highly vascularized leading to rapid cell proliferation; some cells differentiate into osteoprogenitor cells and osteoblasts which produce osteoid within the connective tissue; ossification process through tisue as lamellar bone replaces osteoid
Term
endochondrial ossification
Definition
a hyaline cartilage model is replaced by bone; this is used to form long and short bones; starts with proliferation and hypertrophication of carilage cells (lacunae increase in number and size with very little intercellular matrix); calcified by lime salts; cells below periochondrium differentiate into osteoblasts which deposit a bony thin collar; periosteal buds invade through collar and infiltrate enlarged lacunae into marrow spaces; replacement of lime salts with calcium hydroxyapatites
Term
primary ossification center
Definition
location in diaphysis where endochondral ossification starts
Term
secondary ossification centers
Definition
locations in epiphyses where endochondral ossification occurs
Term
growth of flat bones
Definition
increased size without increased thickness of compact bone; osteoblasts deposit new bone along external surfaces and osteoclasts reabsorb along internal surfaces
Term
appositional growth
Definition
increased diameter via intramembranous ossification on external surface of collar with osteoclast activity on internal surface
Term
longitudinal growth
Definition
sequential zones in growth plate; zone of reserve cartilage, zone of proliferation, zone of maturation and hypertrophy, zone of calcification, zone of ossification
Term
zone of proliferation
Definition
cells arranged in thin oval lacunae begin to align in parallel longitudinal rows which is responsible for the increase in length of cartilage
Term
zone of cartilage calcification
Definition
zone of variable length but always narrow
Term
synovial joints
Definition
characterized by a fibrous capsule filled with synovial fluid and cartilaginous articular surfaces
Term
synovial membrane
Definition
secretes viscous gel to lubricate joint; richly endowed with fenestrated capillaries which allows plasma to leak out
Term
fibroblastic synoviocytes
Definition
add hyaluronic acid to plasma component to produce synovial fluid
Term
macrophage-like synoviocytes
Definition
rounded cells adjascent to synovial space that phagocytized debris
Term
articular cartilage
Definition
provides smooth surface for articulations; surface lacks a perichondrium; collagen fivers arch as surface which allows greater distribution of shear forces; subject to thinning over time
Term
intervertebral discs
Definition
located between the bodies of adjascent vertebrae
Term
annulus fibrosis
Definition
outer fibrous layer composed of fibrocartilage with layers of collagen fibers oriented in 90degree planes
Term
nucleus pulposis
Definition
gel-like material derived from notochord; partially displaced by fibrocartilage in adults
Term
dense regular connective tissue
Definition
composed of densely packed fibers coursing generally parallel to each other. extreme tensile strength
Term
tendon
Definition
composed entirely of collagen fibers coursing precisely parallel. attaches muscle to bone. fibroblasts arranged in rows and flattened between thick collagen fibers. minimum vascularization. fibers bundled into fasicles. contained in a lubricated tough fibrous sheet to minimize friction
Term
ligament (yellow elastic tissue)
Definition
composed of parallel bundles of collagen and elastic fibers. lots of fibroblasts. connect bones within a joint.
Term
primary function of muscle
Definition
contraction to produce movement
Term
muscle fibers
Definition
muscle cells grouped in bundles.
Term
skeletal muscle
Definition
cells fuse together during fetal development. syncytion that may contain several hundred nuclei. nuclei just below sarcolemma and usually flattened. longitudinally oriented actin and myosin
Term
red fibers
Definition
aerobic. small with high myoglobin content and a rich blood supply. able to generate slow but more sustained contractions.
Term
white fibers
Definition
large with low myoglobin content and a minimal blood supply. rapid contractions but easily fatigued.
Term
innervation of skeletal muscle
Definition
muscle fiber dies if this is destroyed
Term
motor unit
Definition
a motor axon and all of the fibers that it innervates. allows several fibers to act as a unit
Term
motor end plates
Definition
found at the neuromuscular junction. motor nerve axon branches into twigs that innervate several fibers. fewer fibers per axon yields finer muscle control.
Term
sensory (muscle spindle and golgi tendon organ)
Definition
provide information about tension of muscle. component of feedback system that maintains muscle tone, proprioception and prevents ripping of muscle.
Term
golgi tendon organ
Definition
encapsulated nerve endings within tendon
Term
muscle spindle
Definition
fibrous capsule containing 5-15 thin intrafusal muscle fibers
Term
muscle damage
Definition
very limited regeneration through satellite cells. replaced by fibrous connective tissue scar. regain size and strength primarily through hypertrophy of remaining fibers
Term
endomysium
Definition
surrounds individual muscle fibers
Term
perimysium
Definition
groups many muscle fibers together to form a fascicle
Term
epimysium
Definition
groups many fascicles together to form a muscle. continuous with tendon.
Term
smooth muscle
Definition
found as layers in walls of hollow organs and as individual cells. cigar shaped cells with central nucleus. myofilaments not well organized. no striations.
Term
focal densities
Definition
anchoring point for smooth muscle
Term
unitary smooth muscle
Definition
cells have synchronized rhythmic contractions stimulated primarily by stretch. patterns modified by hormonal and/or neural input
Term
multi-unit smooth muscle
Definition
precisely controlled by the autonomic nervous system
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