Download Cartilage - UTCOM2013

Microanatomy Characteristics, Unit 2
Warning: Not all of the structures we need to know are listed here!
Cartilage:
Hyaline cartilage: avascular, clear amorphous ground substance
Elastic cartilage: lg round cells, avascular, matrix filled with black staining fibers(3
types)-elastic (Y branching, straight), reticular (right angle branching, squiggly),
collagen(straight unbranched bundles), dots are cross sectional view of fibers, without
stain would look like hyaline cartilage
Fibrocartilage: Primary fiber type=Collagen type I, lrg round cell, not as much grd
substance as hyaline cartilage
Bone:
Osteoclasts: large multinucleated, can sometimes see Howships’ lacunae
Indications of Endochondral Ossification: hypertrophy of cartilage cells, periosteal collar
Indications of internal remodeling:
Interstitial lamellae=osteocytes running through, arching over, but no central
canal, remnants of osteons, is it living or not? Don’t know, may still be connection to bv
somewhere for nutrients?
Resorption tunnel=hole created by osteoclasts, no concentric rings ard it
Closing cone=large hole, bigger than central canal, couple layers only, forming
osteon
Zone of prolif: stacks of coins, process occurring is interstitial growth of cartilage (to be
replaced with bone)
Isogenous grp: more than one cell in each lacuna, indicates growth
Intervertebral Disc: Spongy and compact bone, in between=intervertebral disc, nucleus
pulposis is gelatinous , type of joint=symphysis, cartalaginous, amphiarthroses (slightly
moveable)
Volkmann’s canal:supplies nutrients to BVs of osteons, diagonal canal with BV, no
concentric rings ard it
Canaliculi (tunnels): spidery fibers, don’t extend past cement line, inside them are the
cellular processes
Muscle:
Smooth muscle: Irregularly shaped fibers, round cross-sectional profiles, nucleus is cigar
shaped and very peripherally located-on inside edge of cross-sectional profile, other dark
spots visible are the nuclei of CT, difficult to see cell borders, contorted/corkscrew config
of nuclei=contracted, smooth muscle can be partially contracted so some nuclei can be
seen in contracted position, others in relaxed
Skeletal Muscle: striated voluntary muscle, nuclei also peripherally located, can see
striations, I bands – light stained, A Bands – dark stained, Sarcomere=middle of one I
band to the middle of the next I band, myoglobin staining: dark stained(red) have high
myoglobin content, low glycogen conent, large white fibers have low myoglobin and
high glycogen content, EM Level: T tubules seen at junction of A and I bands, H
bands=thick filaments only, held apart by crossbridging proteins (M line)
Cardiac: Striated appearance, short, branched fibers, centrally located nucleus,
intercalated discs visible on some longitudinal slides-can see dark thin lines(transverse
portion, can’t see lateral portion, just know it’s btw two transverse), endomysial like CT
partially surrounds myocytes-not completely like skeletal
Tendon: (CT, how to tell diff from skeletal muscle) tightly packed collagen bundles are
wavy in longitudinal section and lack cross striations, elongated nuclei squeezed between
the bundles are characteristic, in cross section, the stellate shaped nuclei appear to be
scattered throughout the bundles and not just located at the periphery of the bundles,
many more nuclei per specific area in tendon
Nervous:
Nerve fibers: black, fibers entering muscle---supplying electrical signals for the
command structure; voluntary command starts in cerebral cortex, travels through ventral
horn, Nissl bodies visible in slides stained for ribosomes (the dendrites will be unstained
bc they don’t have a lot of ribosomes), dendrites are thick and taper off, thin axon not
always visible(has constant diameter), white space is myelin coating-not continuous
sheet-Nodes of Ranvier are seen as lines that break it up, myelin makes up most of cell in
cross section, Dark brown lipophilic staining slide: dark stained circles-myelin, white
inside is the axon pointing out at you
Dendritic spines – beaded appearance; increase surface area of receiving info
Motor end plate: specialization of the nerve fiber, tip of nerve fiber embeds itself in
membrane of muscle, forms neuormuscular synapse; speckled appearance
(specializations of junctional folds), number of motor endplates and number of muscle
cells determine the precision, each muscle fiber is innervated by a single motor end plate,
but a given motor axon can innervate many muscle fibers.
Muscle Spindle: designed to detect stretch of muscle; made up of intrafusal fibers;
surrounded by CT fibers, relays info to CNS, identified by a spring-like axon wrapped
around fibers-will see the speckles not the actual axons, made up nuclear bag fibers
(group of nuclei), nuclear chain fibers. In cross section-connective tissue capsule
surrounding cross sections of one to five small intrafusal fibers, can see one nucleus of
the nuclear chain fibers.
Glial cell cytoplasm not a lot of stain-little nuclei, many more of them, primarily support
function, some may be oligodendrctyes-provide myelin coating to a portion of an axon
(internodal segment)