Term
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Definition
| Group of microfilaments running lengthwise in a muscle cell (myofiber), seen as dots in cross-section |
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Term
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Definition
| Individual muscle cell, anatomical syncytium, multinucleate running length of cell |
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Term
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Definition
| Surround entire muscle, dense irregular CR, contains vascular and nerve supply |
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Term
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Definition
| Surround 1 fascicle, less dense irregular collagenous CT, contains smaller branches of nerves and blood supply |
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Term
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Definition
| Surrounds 1 muscle fiber, loose CT, reticular and collagen; contains capillaries and fine neuronal branches |
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Term
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Definition
| Point where muscle meets dense regular CT (e.g. muscle meets tendon) |
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Term
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Definition
| Myoblasts which fuse end to end, central nuclei when immature; develop from paraxial mesoderm; develop into myofibers |
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Term
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Definition
| Persistent stem cells, mononucleate, between fibers, regenerative, only used when necessary |
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Term
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Definition
| Dilated flattened end of Sarcoplasmic Reticulum containing ryanodine receptors which release Ca to start contraction |
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Term
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Definition
| T-tubule + 2 SR terminal cisternae, located at A-I junction in skeletal muscle; site of excitation-contraction coupling |
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Term
| DHPR-RyR in skeletal muscle |
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Definition
| Conformational change in DHP receptor --> change in associated RyR --> RyR opens for Ca to leave SR and enter cytosol |
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Term
| Which type of skeletal muscle has prominent glycogen? |
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Definition
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Term
| Which type of skeletal muscle has more mitochondria? |
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Definition
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Term
| I band, H band, A band in contraction |
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Definition
| I band narrower, H band narrower, A band same size |
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Term
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Definition
| Anchor thick filaments of sarcomere to other filaments, titin at M-line |
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Term
| M-line thick filament anchoring proteins |
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Definition
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Term
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Definition
| Accessory protein extending from M-line to Z-line, important for stabilizing thick filaments |
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Term
| Thin filament polarization |
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Definition
| Highly polarized with positive (+) end binding at Z-line via alpha-actinin |
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Term
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Definition
| Binds + end of actin filaments to Z-line |
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Term
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Definition
| Runs length of filament, helps bind thin filament to Z-line; keep thin filament lengthwise in place |
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Term
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Definition
| Filament runs in grooves between F-actin molecules; goes deeper into the actin molecule to expose TnC during contraction; troponin-tropomyosin complex |
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Term
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Definition
| Binds tropomyosin via TnT; binds Ca via TnC; binds actin via TnI, inhibiting actin-myosin interaction |
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Term
| Muscle intermediate filaments |
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Definition
| Desmin and vimentin; secure Z-lines in adjacent myofibrils; attach Z-lines to sarcolemma for overall stability |
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Term
| Clinical correlation of Muscular Dystrophy |
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Definition
| Mutation in dystrophin complex which helps anchor/organize/secure to sarcolemma; leads to progressive weakness and death |
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Term
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Definition
| Form muscle spindles, monitor changes in muscle length |
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Term
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Definition
| Stimulate contraction; supplied by 1 neuron (1 neuron can supply many fibers); connect through NMJ |
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Term
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Definition
| Present in ventral horn of spinal cord, sends out long processes into muscle cells, connect at NMJ |
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Term
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Definition
| Motor neuron + all muscle fibers it controls (1:1 eyes, 1:many in thighs); all contract in unison; myelinated axons with many arborizations |
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Term
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Definition
| No myelin sheath, dilate at NMJ; synaptic vesicles with ACh, many mitochondria; sits in primary synaptic cleft |
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Term
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Definition
| Denervation of 1 group at a time; groups of atrophying muscle fibers with their affected motor neurons; mostly in anterior horn in brain, leading to loss of motor control |
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Term
| Clinical Correlate: Myasthenia gravis |
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Definition
| Auto-antibodies block ACh receptors at NMJ, junctional folds are lost and synaptic cleft widens; progressively weaker muscles |
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Term
| Sliding Filament Model of Contraction |
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Definition
| Motor neuron AP to NMJ --> ACh release in synaptic vesicles, bind receptors on myofiber --> depolarization signal to T-tubules to DHP receptors --> act on RyR, Ca release from SR --> Ca binds TnC, expose myosin-binding site --> myosin head bind actin, ATP hydrolysis to release --> myosin pull actin past, repeated cross-bridge cycling --> Ca pumped back into SR |
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Term
| Clinical Correlate: Rigor Mortis |
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Definition
| No O2 to make ATP, Ca diffuse in cytosol to bind troponin, myosin-actin cannot decouple; muscles contracted until myosin heads degrade |
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Term
| Slow-twitch muscle fibers |
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Definition
| Red muscle, oxidative, endurance, Type I; abundant mitochondria, myoglobin, blood supply, wider Z-lines, small NMJ |
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Term
| Fast-twitch muscle fibers |
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Definition
| White muscle, glycolytic, strength, Type II; abundant glycogen, fatigue quickly, less blood supply, fewer mitochondria |
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Term
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Definition
| Binds Z-lines to plasma membrane; keep everything in order; complex associated with laminin in basal lamina |
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Term
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Definition
| Stain used to tell red muscle and white muscle apart; most muscles have different ratios of white:red muscle but have both |
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Term
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Definition
| Epicardium (CT with mesothelium, fatty), Myocardium (muscular wall), Endocardium (thin CT with endothelium, lines vessel of heart) |
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Term
| Important characteristics of cardiac muscle (3) - basic |
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Definition
| Striated; involuntary; functional syncytium, not structural syncytium (act in unison) |
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Term
| Additional important characteristics of cardiac muscle |
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Definition
| 1-2 nuclei per cell; end-to-end attachment by intercalated disks; central nuclei; branching fibers; high endurance; intermediate size (smaller in atria); rhythmic contraction; sarcomere like skeletal; organelles near poles of nuclei |
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Term
| Area around nucleus in cardiac muscle |
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Definition
| Pale area (glycogen) and cluster of organelles |
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Term
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Definition
| Fibers vary in shape and size due to branching |
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Term
| Cardiac muscle innervation |
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Definition
| No direct innervation! Impulse initiated by cells in conduction system; regulated by autonomic nervous system, conduction through normal cells and PURKINJE fibers |
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Term
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Definition
| Most mitochondria, lipid droplets, and glycogen; Dyad at Z-band; DHPR dispersed (not tetrads), intercalated disks |
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Term
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Definition
Physically attach and electrically couple adjacent cells (end-to-end)
Longitudinal: gap junctions, demosomes
Transverse: Fascia adherents, maculae adherents (desmosome) |
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Term
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Definition
| Densely packed cristae; produce high levels of ATP for greater endurance |
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Term
| Impulse conduction in cardiac muscle |
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Definition
| SA node --> AV node --> AV bundle --> bundle branches; passes through Purkinje fibers |
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Term
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Definition
| Smaller diameter, more CT separation, attach by gap junctions |
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Term
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Definition
| Large diameter, low density, more glycogen; couple by gap junctions; branching bundles in subendocardium toward apex |
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Term
| Smooth muscle characteristics |
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Definition
| Spindle shape (thicker in middle); central nucleus; couple with gap junctions, contract in unison; ANS control; smallest diameter; single or group innervation |
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Term
| Examples of smooth muscles |
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Definition
| Walls of tubular/sac-shaped organs; blood vessels; uterus (contraction), GI (peristalsis); slow sustained contraction with low ATP usage |
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Term
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Definition
| Single central, elongated nucleus; corkscrew appearance when contracted; organelles near nucleus, eosinophilic |
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Term
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Definition
| swelling of ANS axons with NT in vesicles; enlargement of passing fiber, NTs diffuse across space by cell |
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Term
| Single-unit vs. Multi-unit smooth muscle |
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Definition
Single-unit - nerve fiber synapse on few fibers, spread to more cells by gap junctions; single unit (BV, GI, uterus)
Multi-unit - individual innervation (vas deferens, iris) |
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Term
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Definition
| Anchor actin, IF, similar to Z-line, attach sarcoplasm to sarcolemma; joined in network by IFs, transmit contractile forces |
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Term
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Definition
| Invagination of smooth muscle cell membrane; look like pits, close to SR, similar function to t-tubules, allow Ca entry |
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Term
| Smooth muscle actin filaments |
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Definition
| Different isoforms; caldesmon, calponin, NO TROPONIN, leitonin, insert into dense bodies |
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Term
| Smooth muscle myosin filaments |
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Definition
| Side-polar; stack of myosin dimers; no bare zone; surrounded by rosette of thin filaments |
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Term
| Smooth muscle contraction |
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Definition
| Stretch-activated ion channels; NT from ANS; open Ca channels; affected by hormone activation as well |
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Term
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Definition
| Ca mostly from extracellular source, not stored in cell (no t-tubules) |
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Term
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Definition
| Important protein in smooth muscle; binds Ca, complex activates MLCK, which phosphorylates myosin, activating the actin-binding site |
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Term
| Smooth muscle ATP hydrolysis |
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Definition
| Slow leading to sustained contraction; can maintain in "latch state" |
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Term
| Smooth muscle contraction |
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Definition
| Shorten cell in all directions, "bubbles", due to Ca-CaM interaction; change in length not due to sarcomeres but longer thin filament lengths |
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Term
| Smooth muscle organization - large-scale |
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Definition
Well-defined layers/longitudinal arrangement - peristalsis/tone
Interlacing bundles - expand quick or over long time - uterus/bladder |
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Term
| Additional capabilities of smooth muscle |
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Definition
| Make collagen type III + IV, other ECM molecules; make Collagen type I and elastin in tunica media of BV; divide in response to injury |
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Term
|
Definition
| Brain, spinal cord, optic nerve, retina, olfactory tract+bulb |
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Term
|
Definition
Derive from neural tube; oligodendrocytes form myelin, 4 specialized glia
Supporting cells: astrocyte, microglia, oligodendrocyte, ependymal cells |
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Term
|
Definition
Derive form neural crest; Schwann cells myelinate; satellite cells
Afferent (inward, sensory) and Efferent (outward, motor)
Motor --> Somatic and Autonomic --> Sympathetic and Parasympathetic --> Enteric (gut motility) |
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Term
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Definition
| Transmit impulse in response to stimuli; process information; activate muscle; heart rhythm; regulate effectors (glands), homeostasis with endocrine system |
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Term
|
Definition
Gray matter: many neurons, cell bodies, glia and axons, less myelinated
White matteR: more myelinated axons (lipid), axons, glia, few cell bodies |
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Term
|
Definition
| Functional unit of nerve tissue, make action potential, electrical or chemical activation, NOT REPLACED IN ADULTHOOD, average neuron receives 1500 synapses |
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Term
|
Definition
| Large euchromatic nucleus with 1+ large nucleoli, large RER, abundant Golgi, free polysomes (Nissl bodies), lipofuchsin bodies, neurofilaments, melanin inclusions (rare); large cell body |
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Term
|
Definition
| Lysosomes which can no longer function and accumulate junk; occurs because neurons last entire lifetime |
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Term
|
Definition
| Branch into smaller collateral branches; contact cells at boutons; axon hillock --> axon terminal; MT's with + end distal |
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Term
|
Definition
| Multiple, form dendritic tree; form on cell body or axon; never myelinated; receptive surface at synaptic junction, specific MAPs (MAP2); Nissl bodies present in proximal area |
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Term
|
Definition
| Loss of Nissl bodies, oddly located nucleus (due to injury), return to normal if successful recovery |
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Term
|
Definition
| Much smaller than neuron cell body |
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Term
|
Definition
| Specialized gap junction, channels allow current flow, rare - places where synchrony needed (smooth muscle, retina, bronchioles) |
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Term
|
Definition
One main dendritic process, one main axonal process
Retina, olfactory epithelium, some interneurons |
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Term
|
Definition
| Multiple dendritic trees, one axon (common); includes pyramidal cells |
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Term
|
Definition
| Multiplar neuron, large extensive dendritic trees |
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Term
|
Definition
| Special sensory, 1 main branch coming out from body with axon going one way and dendrite going the other way; information goes in ONE way toward CNS (dorsal root ganglion!) |
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Term
|
Definition
| Acetylcholine, Norepinephrine, Epinephrine, some peptides, Nitric Oxide (NO) |
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Term
|
Definition
| Glu (excitatory), GABA, Gly (inhibitory), dopamine, serotonin, acetylcholine, norepnephrine |
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Term
|
Definition
| Synthesized in cell body, transport to axon in vesicles |
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Term
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Definition
| Large % of CNS; support + regulate microenvironment of neurons, can divide; only see nuclei by LM; form BBB, sequester ions or excess NT, form myelin, scar formation |
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Term
|
Definition
| Helps form BBB, star-shape, sequester excess ions; form glial scar; IF is GFAP |
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Term
|
Definition
| Present only in development - important for axon guidance; loss may be linked to inability to regenerate nervous tissue |
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Term
|
Definition
| Myelinate ONLY in CNS; can myelinate many axons/neurons |
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Term
|
Definition
Axon forms and reaches synapse --> axon secretes neuregulin (more made = thicker myelin sheath) --> myelin sheath made
Missing Oligo --> missing myelin sheath in segment --> slow signal or lack of propagation of signal
Dark cytoplasm in EM, reaches out to axons |
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Term
|
Definition
Inflammatory and immune response; mesodermal origin; give rise to CNS macrophages and monocytes
M1 remove debris, M2 repair; timing + presence important |
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Term
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Definition
| Epithelium lining ventricles and central canal of spinal cord, makes CSF; single layer, cuboidal-columnar; taller in choroid plexus |
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Term
|
Definition
| Flat, surround cell body in peripheral ganglia, support neurons, regulate environment; closer encapsulation in DRG than in ANS |
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Term
|
Definition
| PNS myelination; only 1 segment of 1 axon; can divide at site of nerve injury, help guide regenerating axons |
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Term
|
Definition
Formed by Oligo/Schwann due to neuregulin secretion; alternating dark and light in EM (dark = myelin)
Each segment made by wrapping around of single Schwann cell or single process of oligodendrocyte |
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Term
| Wrapping of myelin sheath |
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Definition
| Occurs in spiral, squeezes cytoplasm out of own cell; major dense line and intraperiod line |
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Term
|
Definition
| Fused cytoplasmic surfaces in myelin spiral (darkest) |
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Term
|
Definition
| Fused extracellular surfaces in myelin spiral (lighter than major dense line) |
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Term
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Definition
| Winding part of Schwann cell/oligodendrocyte; inner mesaxon = inner end of spiral; outer mesaxon = outer end of spiral |
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Term
|
Definition
| About 200 µm between Nodes of Ranvier (site of saltatory conduction) |
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Term
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Definition
| Tubular channel when outer cytoplasm of myelinating cell near nucleus attaches to inner cytoplasm near the axon it has wrapped around; important for maintenance and turnover of myeling and cytoplasmic components; cone-shaped space/imperfection |
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Term
| CNS/PNS specific proteins and glycoproteins |
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Definition
CNS - Nogo-A/Nogo66, MAG, OMgp
PNS - MBP, PLP, P0 |
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Term
|
Definition
| Dense CT, looser extending in to fill spaces, continuous to dura mater |
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Term
|
Definition
| 2-5 layers of squamous myoepithelial connected by tight junctions; basal lamina around each layer, BV present, form Blood-Nerve barrier |
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Term
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Definition
| Engulf Schwann cell and axon; reticular collagen, few fibroblasts; loose CT |
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Term
|
Definition
| Present in ganglion, nerves DO NOT contain neuronal cell bodies |
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Term
|
Definition
| Large alpha neurons in ventral horn, send axon out, synapse on individual muscle fiber, no synapses in pathway until skeletal muscle |
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Term
|
Definition
| 2 cell pathway: column in inf. lat. spinal cord send out ventral root to autonomic ganglion --> effector organs |
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Term
|
Definition
| Located together in sympathetic chain |
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Term
|
Definition
| Psuedounipolar; large cell body, central nuclei, close cluster, continuous capsule by satellite cell; dense CT capsule around all; peripheral receptor to spinal cord |
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Term
|
Definition
| Input from presynaptic neurons, multipolar, eccentic nuclei, more scattered neurons, discontinuous satellite cell layer |
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Term
| Sympathetic nervous system |
|
Definition
| Fight or flight, function under stress; 2 chains along vertebral column (paravertebral/chain ganglia), few unpaired along aorta; preganglionic axons cholinergic, postganglionic axons usually adrenergic |
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Term
|
Definition
| Chain of ANS ganglia along vertebral column; 2 paired chains |
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Term
|
Definition
| Few unpaired ganglia along aorta, belongs to ANS |
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Term
| Parasympathetic nervous system |
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Definition
| Rest and relax; ganglia close to or in target organ (terminal ganglia); preganglionic axon from S2-S4 or CN 3,7,9,10; long preganglionic axon; short postganglionic axon; ACh used for both |
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Term
|
Definition
| Parasympathetic ganglia close to or inside target organs |
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Term
|
Definition
| Preganglionic Parasympathetic axons originating from S2-S4 or CN 3, 7, 9, 10 |
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Term
| Sympathetic + Parasympathetic innervation |
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Definition
| Innervate all same organs EXCEPT sweat glands and adrenal glands only have sympathetic innervation |
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Term
| Secondary NT neuromodulator examples (3) |
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Definition
Sympathetic ACh activate nicotinic (fast) or muscarinic (slow) receptors
Norepinephrine produce vasoconstriction + inhibit further release at neurovascular junction
Co-transmission (e.g. ACh and VIP) at secretomotor junction |
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Term
|
Definition
| GI for peristalsis and secretion; independent operation, regulated by Para/Sympathetic systems; ganglia in 2 plexuses; susceptible to Crohn's IBS, infectious diarrhea, food poisoning |
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Term
|
Definition
| Auerbach's plexus, ganglia of Enteric NS; between circular and longitudinal layers of muscle |
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Term
|
Definition
| Meissner's plexus, ganglia of Enteric NS; just deep to mucosal layers (inside muscular layers) |
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Term
|
Definition
| Developmental absence of ganglia in enteric NS; ANS can somewhat replace by inserting into gut with ganglia scattered throughout length of gut, diagnosed early |
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Term
| Presynaptic NMJ specializations |
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Definition
| Enriched mitochondria, neurofilaments, ACh in synaptic vesicles which fuse with active zone, capping by non-myelinating Schwann cells |
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Term
|
Definition
| Are where synaptic vesicles fuse with the membrane to release ACh into the neuromuscular junction |
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Term
| Postsynaptic specialization |
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Definition
| High density of ACh receptors, junctional folds to increase surface area (primary and secondary), enriched mitochondria |
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|
Term
| Smooth muscle motor nerve endings |
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Definition
| NT released from varicosities further away, no NMJ, 1 varicosity per unit of muscle cells (1 or many) |
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Term
|
Definition
| Antibodies to presynaptic Ca channels, impair ACh release |
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|
Term
| Myasthenia gravis antibodies |
|
Definition
| Antibodies to postsynaptic ACh receptors |
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Term
|
Definition
| Bacterium, block synaptic vesicle fusion |
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Term
|
Definition
| Tick salivary gland, inhibit Ach release |
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|
Term
| Clinical Correlation: Autoimmune diseases (2) and Neurotoxins (5) |
|
Definition
Lambert-Eaton disease and Myasthenia gravis
Botulinum toxin, tick paralysis, bungarotoxin, latrotoxin, tetanus toxin |
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Term
|
Definition
| Snake, block ACh receptor |
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Term
|
Definition
| Spider, too much synaptic vesicle fusion, ACh release |
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Term
|
Definition
| Bacterium, block fusion from GABA; not enough inhibitory signal throughout nervous system |
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Term
| Sensory nerve ending adaptation |
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Definition
| Fast-adapting available for new stimulus quickly (fine touch); slow-adapting resents over longer time (pain) |
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Term
|
Definition
| Vibration detected in deep dermis or hypodermis; free nerve fiber in tissue, tissue deformation due to pressure causes depolarization in nerve ending --> action potential |
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|
Term
| Somatosensory receptor types (6) |
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Definition
| Mechanoreceptor (pressure, vibration, sound), Photoreceptor, Nociceptor (tissue damage/pain), Chemoreceptor (O2, pH, organic molecules), Proprioceptor (position), Thermoreceptor (temperature) |
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Term
|
Definition
| No capsule, associated with unmyelinated axons/non-myelinating Schwann cells, epidermis or hair bulb; pain, temp touch; cornea; silver stain to see; |
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Term
|
Definition
| Expansion of denuded terminal tips, associated with special non-neuron cells (e.g. Merkel's disk) |
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Term
|
Definition
| Large nerve ending near Merkel cell (lobed nucleus); basal layer of epidermis; respond to light touch, steady pressure (slow-adapting) |
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Term
|
Definition
| Lobed nucleus, many secretory vesicles, near nerve terminal, associated with Merkel's disk |
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Term
|
Definition
| Detects continuous touch or pressure (slow-adapting) |
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Term
|
Definition
Skin: Pacinian corpuscules, Ruffini endings, Meissner's corpuscules
Muscle: Muscle spindles, Golgi tendon organs
Oropharynx/eye: Krause's end bulbs
Surrounded by layers of CT and capsules (corpuscules) |
|
|
Term
|
Definition
| Cylindrical, perpendicular to skin; horizontal stacks of flattened Schwann cells; axon end in spiral course; present in dermal papillae esp. glabrous skin; fast-adapting to light touch, texture, rapid or irregular pressure |
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Term
|
Definition
| Give power to muscle (functional contractile element) |
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Term
|
Definition
| Encapsulated sensory ends; sense stretch, pressure, length, and spatial position |
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Term
|
Definition
| Skeletal muscle; intrafusal fibers present (nuclear bag or chain fibers in capules); afferent and efferent innervation |
|
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Term
|
Definition
| Nuclei lined up along length |
|
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Term
|
Definition
| Nuclei bunched, piled up on top of each other |
|
|
Term
| Muscle spindle afferent innervation |
|
Definition
| Large caliber myelinated Ia fibers (every spindle receives one) - terminal complex is primary sensory ending, smaller caliber myelinated II fibers - ending is secondary sensory ending |
|
|
Term
| Muscle spindle efferent innervation |
|
Definition
gamma-motor neuron; contracts intrafusal fibers, adjust spindle sensitivity
Shorter intrafusal fiber --> less stretch required to excite spindle afferents |
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Term
|
Definition
| Passive stretch --> Ia afferent fires --> activate alpha-motor neuron of flexor AND activate inhibitory interneuron synapsing on alpha-motor neuron of extensor --> flexion |
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|
Term
| Examples of muscle spindle reflex |
|
Definition
Biceps tendon reflex test (C5-C6 integrity)
Knee-jerk reflex (lumbar spinal integrity) |
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|
Term
| Effects on knee-jerk reflex |
|
Definition
Lose descending motor control - more robust response
Dorsal or ventral root damage - no reflex at all |
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Term
|
Definition
At myotendinous junction; arranged in series with skeletal muscle cells
Innervated by free Ib afferent nerve, interwoven with collagen fibers, no efferent innervation (more sensitive to tension force)
More sensitive to muscle contraction than stretch (monitor load or tension on muscle) |
|
|
Term
| Protective Golgi tendon reflex |
|
Definition
| Muscle contraction in flexor --> stretch Golgi tendon organ --> 1b myelinated sensory fiber activated --> fire alpha-motor neuron innervating extrafusal fibers of flexor AND inhibit interneuron synapsing on alpha-motor neuron of flexor --> contract extensor, relax flexor, release heavy load |
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Term
|
Definition
| Circumferential lamellae of flattened fibroblasts, joined by desmosomes; capsular space contains tissue fluid |
|
|
Term
|
Definition
Structural: posture, movement, protect organs, support soft tissues
Endocrine: osteocalcin regulate insulin production, signal fat to produce adiponectin
Metabolic: Hematopoiesis, storage/metabolism of minerals |
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Term
|
Definition
| Where bone growth primarily occurs; in long bone, starts in diaphysis (primary), separately later at epiphysis (secondary) |
|
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Term
|
Definition
| Shaft of bone, mostly hollow with marrow inside |
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Term
|
Definition
| Bone starts to narrow into shaft below epiphyseal line |
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Term
|
Definition
| Bone ends, joint surfaces, muscle attachment points |
|
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Term
|
Definition
| Inner and outer cortex of compact bone, internal diploe of cancellous bone; no marrow cavity, marrow in trabeculae of spongy bone |
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|
Term
| Dynamic structure of bone |
|
Definition
| Repair, remodel, optimize structure throughout lifetime; prevent overmineralization (become brittle), imbalance leads to fracture susceptibility |
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Term
|
Definition
| Bone crystal + collagen --> collagen fibril --> collagen fiber --> lamella with Haversian canals --> osteon --> cortical/cancellous bone |
|
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Term
|
Definition
| Trabecular; Spongy; plates in interconnected struts (trabeculae), more porous; flat bones of skull, end of long bones, vertebrae |
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Term
|
Definition
| Cortical; densely packed bone matrix, more bone than space; outer cortex of all bones, shaft of long bones |
|
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Term
|
Definition
Woven - tissue in random fashion, laid down first
Lamella - organized layers of tissue |
|
|
Term
| Bone ECM contents and their functions |
|
Definition
Organic material (e.g. collagen) - flexibility, tensile strength
Inorganic material (e.g. Ca) - rigidness, compressive strength |
|
|
Term
| Ground section vs. Decalcified section |
|
Definition
Ground - study inorganic component
Decalcified - study organic parts |
|
|
Term
|
Definition
| 90% Collagen Type I, 10% ground substance with proteoglycans (GAGS, proteoglycans, hyaluranon, aggrecan) and 4 glycoproteins (osteocalcin, osteonectin, osteopontin, sialoproteins) |
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Term
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Definition
| Hormone; bind hydroxyapatite; stimulate insulin production and fat metabolism |
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Term
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Definition
| Bind calcium, regulate mineralization (organic ECM of bone) |
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Term
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Definition
| Bind hydroxyapatite, adhere cells to matrix |
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Term
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Definition
| Cell adhesion in bone (organic ECM of bone) |
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Term
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Definition
| Ca compound crystals; fiber formation THEN calcification |
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Term
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Definition
| Initial bone deposits that have undergone fiber formation but not calcification |
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Term
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Definition
| Determined, not differentiated; mesenchymal origin; inner periosteum or endosteum linings; look like fibroblast; divide into osteoblasts |
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Term
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Definition
Synthesize bone, secrete collagen and ground substance as osteoid and matrix vesicles (make mineral part)
Receptors for PTH and Vit D3 to regulate osteoclast activity, Ca levels |
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Term
| Osteoblast location/composition |
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Definition
| Surface of remodeling bone; cuboidal; looks like protein-secreting cell; gap junctions, fewer than osteocytes; estrogen receptors; alkaline phosphatase on surface (marker for cell turnover rate) |
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Term
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Definition
| Become osteocytes when surrounded by matrix they make OR quiescent bone lining cells which can later become osteoblasts |
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Term
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Definition
| Buried in mineralized bone matrix, reside in lacunae; communicate through canaliculi, connect by gap junction; small amount of resoprtion through osteolytic osteolysis |
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Term
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Definition
| Reduced rER, reduced Golgi, mineral homeostasis, mechanosensory in stimulation of remodeling; heterochromatic nucleus, glycogen accumulation |
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Term
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Definition
Resoprtion of bone; large, multinucleate (syncytium), along resoprtion surface in resorption bay/Howship's lacunae
Stimulated by PTH, inhibited by calcitonin |
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Term
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Definition
| Long cell process of osteocyte running in small, fluid-filled canal space through mineral |
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Term
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Definition
| Resoprtion bay - "bites" osteoclast has taken out of bone |
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Term
| Ruffled border and clear zone |
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Definition
| Zone of osteoclast contact with bone; actin in clear zone around ruffled border sealing region to bone surface |
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Term
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Definition
| Eosinophilic (much protein), increased MT, rER, Golgi, lysosomes; releases acid to dissolve mineral crystals |
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Term
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Definition
| Immature, primary; area of rapid growth; only in adults during fracture repair or pathology, non-lamellar; can become cortical or cancellous, replaced by lamellar bone; random fibers and mineral; highly cellular; more ground substance, more porosity, less dense |
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Term
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Definition
| Mature, throughout life; sheets of aligned collagen (lamellae), found in cancellous and compact tissue; slow deposition, more organized, stronger, resist loads better |
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Term
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Definition
| Linear sheet encircling bone; outer lamella deep to periosteum, inner lamella near endosteum |
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Term
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Definition
| Layers of lamellae around Haversian canal; long tubular, branching, longitudinal through bone, formed from secondary remodeling; only in compact bone where internal blood supply needed; increases with age |
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Term
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Definition
| Border of Haversian system; osteocytes communicate via canaliculi inside cement lines but cannot cross through |
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Term
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Definition
| Vascular channel through center of osteon with blood vessels and nerves |
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Term
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Definition
| Vascular channel linking neighboring osteons' Haversian canals |
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Term
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Definition
| Remnant of old Haversian system, result of remodeling |
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Term
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Definition
Cover exterior of bone except articular surface, continuous with tendon CT and skeletal muscles; appositional growth
2 layers: outer fibrous layer and inner cellular layer |
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Term
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Definition
| thin 1 layer CT over interior surface of bone, cellular |
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Term
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Definition
| External surface of bone at joint (articular surface at synovial/cartilagionus joint); extensive, semi-rigid ECM, mostly avascular, interstitial AND appositional growth; much ground substance and water, viscoelastic |
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Term
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Definition
| Support/flexible soft tissue, skeletal precursor; cushion and move joints |
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Term
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Definition
Hyaline (most, type II), elastic (Type II + elastic), fibrocartilage (type I)
Note: types are Collagen types present |
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Term
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Definition
dense, Type I collagen, surround cartilage structures (except articular surface of joints, fibrocartilage areas), BV present
Outer fibous layer, inner cellular layer; appositional growth through chondroblasts near here |
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Term
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Definition
| Inner layer of perichondrium, committed stem cells differentiating into chondroblasts |
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Term
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Definition
| Inner layer of perichondrium, secrete cartilage matrix until completely surrounded (appositional growth) |
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Term
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Definition
| Chondroblast completely surrounded by matrix, located in lacunae; mitosis continues and forms up to 8 cells in isogenous group; active basophilic and clear areas |
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Term
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Definition
| Small grouping of up to 8 cells from one parent in (hyaline) cartilage with territorial matrix in between |
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Term
| Chondrocyte ultrastructure |
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Definition
| Irregular border and filipodia (young); standard secretory cells (older), heterochromatic with many accumulations of lipid, glycogen (aging) - distinguish by location at end of bone tissue |
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Term
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Definition
| Sulfated GAGs, basophilic (PAS +ve), fibers, ground substance, glycoproteins (chondronectin); sulfated GAGS make matrix basophilic (eosinophilic if not preserved well) |
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Term
| Territorial and Interterritorial matirx |
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Definition
| Territorial is more recent deposit, closer to chondrocytes, higher [GAG], less water, near lacuna |
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Term
| Cartilage Ground substance |
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Definition
| Sulfated GAGs, proteoglycan, hyaluronan, aggrecan aggregates (more extensive than in bone) |
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Term
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Definition
| 60-80% weight, bind aggrecan aggregates, provide more resilience and resist compression |
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Term
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Definition
| Most mesoderm except branchial arch from neural crest ectoderm |
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Term
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Definition
| Nutrition source for very rapidly growing cartilage |
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Term
| Cartilage appositional growth |
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Definition
| Inner surface of perichondrium, chondroblasts secreting matrix to periphery |
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Term
| Cartilage interstitial growth |
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Definition
| Mitotic divisions and matrix made by chondrocytes enclosed in matrix; leads to rapid length growth without disrupting articular suface - essential for endochondral ossification |
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Term
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Definition
| Deep in cartilage, no sufficient access to nutrients in perichondrium; atrophy, more water, calcification, arthritic changes at joint surfaces(?) |
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Term
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Definition
| Very limited; produce matrix too slow to repair damage; can be replaced by vascularized CT in acute injuries or remain as fibrous tissue |
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Term
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Definition
Most common, type II collagen, glassy, non-fibrous matrix
Fetal and growing skeleton pre-ossification, persist at growth plate until skeletal maturity, articular surface of synovial joint, respiratory tract, medial end of ribs |
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Term
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Definition
Most cellular, larger cells than hyaline; yellowy and opaque, elastic fibers and sheets seen with H&E
Eustachian tubes, external auditory canals, larynx, epiglottis |
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Term
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Definition
Type I collagen, no perichondrium, near dense CT, fibrous-looking matrix; isogenous clusters of columns; great tensile strength
Annulus fibrosis, tendons around bony prominences, symphysis pubis, ligaments, joint menisci; places with compressive and tensile stresses in different directions |
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Term
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Definition
| First found by changed structure of articular cartilage; surface becomes undulating w/ shred-like projections; loss of cartilage affects underlying bone; chronic inflammation affects synovial fluid and membrane |
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Term
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Definition
| Arthrosis, meeting place between bones |
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Term
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Definition
| Least mobile, 2 bones united by fibrous CT, essentially fixed |
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Term
| Fibrous joint examples (3) |
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Definition
| Sutures, Syndesmoses, Gomphoses |
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Term
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Definition
| Joint between bones of skull - squamous or serrated |
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Term
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Definition
| Sheath of fibrous tissue (e.g. interosseous membrane) |
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Term
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Definition
| Fibrous articulation between tooth and alveolar bone via Sharpey's fibers |
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Term
| Cartilaginous joint types (2) |
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Definition
| Synchondroses and Symphyses; more mobile than fibous |
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Term
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Definition
| Primary cartilaginous joint - temporary during growth (growth plates); hyaline cartilage replaced once growth ceases by synostosis (bony union) of epiphysis and diaphysis in long bone |
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Term
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Definition
| Bony union to replace hyaline cartilage in long bone - union of epiphysis and diaphysis |
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Term
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Definition
| Secondary cartilaginous joint; bone surface covered by fibrocartilage, then hyaline cartilage; limited movement, fuse with age (e.g. intervertebral disk) |
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Term
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Definition
| Diarthroses - bony articulation in contact, not continuity with one another; low friction due to synovial fluid; articular surface with hyaline cartilage, no nerves or BVs, arched collagen configurations; fibrous joint capsule cuff around articular end |
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Term
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Definition
| Lines non-articular parts of synovial joint; contains A cells (remove debris) and B cells (secrete components of synovial fluid) |
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Term
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Definition
| RIchly innervated, rich blood supply, many anastomoses; bursae around joints near areas where tendons insert into bones |
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Term
| Transition form articular cartilage to bone |
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Definition
| Bone --> Calcified cartilage --> Radial layer --> Transitional layer ---> Tangential layer; orientation of cells and fibers varies (transverse near articular surface, longitudinal/perp in radial layer) |
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Term
| 2 types of bone formation and original derivative |
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Definition
Intramembranous ossification, endochondrial ossification; both formed from mesenchyme
Osteoid --> woven bone --> lamellar bone |
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Term
| Intramembranous officiation (I.O.) |
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Definition
Directly from mesenchyme; formed by periosteum of all bones; occurs in middle (diaphysis) of bone - differentiation into osteoblasts
Flat bones of skeleton (skull, face), non-weight bearing, low compressive strain |
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Term
| I.O. Vascularization and condensation |
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Definition
| Vascularization and condensation of vascular tissue at primary ossification center; begins at 8 weeks gestation; mesenchymal cells aggregate |
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Term
| I.O. Differentiation and deposition |
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Definition
| Mesenchymal stem cell --> osteoprogenitor --> osteoblast --> lay down osteoid --> mineralize into woven bone spicules --> larger trabeculae; nearby mesenchymal cells proliferate and differentiate |
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Term
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Definition
| Bone develop around BV, BV bring in osteoclast to shape bone as size increase, osteoblasts lay down lamellar bone, inside of flat bone maintained as cancellous bone, apposition from periosteum forms outer cortical surfaces; mesenchyme membranes retained as inner and outer periosteum |
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Term
| Endochondral Ossification |
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Definition
| Cartilaginous precursor; allow for growth in length without disrupting joint surface; begin in week 12 gestation, continue into adulthood |
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Term
| E.O. Primary ossification center |
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Definition
| Chondrocytes stop proliferating, hypertrophy, make collagen type X, induce perichondrium cells to become osteoblasts which form bony collar; chondrocytes lose blood supply (bony collar) and die, matrix calcifies, secretion of signaling factors |
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Term
| E.o. Primary ossification - osteogenic bud |
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Definition
Enters vacated area from dead chondrocytes, osteoprogenitor cells make osteoblasts, which start depositing bone; mixed spicules of woven bone and calcified cartilage; zone of ossification spreads in both directions
Calcified cartilage = basophilic; new bone = eosinophilic
Bud persists as nutrient artery |
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Term
| Secondary ossification center |
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Definition
| Form at both epiphyses of forming bone; start with hypertrophy of chondrocytes, proceed in same method as primary ossification; complete ossification except at growth plate and articulate surface; bone formed on diaphyseal side of growth plate |
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Term
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Definition
| Growth plate, site of continued lengthwise interstitial growth of cartilage; persists until the epiphyseal plate ossifies after puberty to end bone growth |
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Term
| Zones of secondary ossification |
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Definition
| Zone of reserve cartilage, Zone of proliferation, Zone of hypertrophy, Zone of calcification, Zone of ossification |
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Term
| Zone of reserve cartilage |
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Definition
| Cartilage with some mitotic activity, mostly resting |
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Term
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Definition
| Fast chondrocyte proliferation, form isogenous rows parallel to growth |
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Term
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Definition
| Chondrocytes mature, hypertrophy, start to die |
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Term
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Definition
| Chondrocytes dead, matrix becomes calcified |
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Term
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Definition
| Osteoprogenitor cells invade, become osteoblasts, deposit bone, mixed spicules, resorbed or replaced by lamellar bone |
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Term
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Definition
| Coordinated deposition and resorption of bone at different sites along surface; reshape bone in response to stress; higher rate during growth and development, slower in adults |
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Term
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Definition
| Old metaphysis incorporated into diaphysis |
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Term
| Diaphyseal enlargement and drift |
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Definition
| Increase bone diameter; alter curvature of bone |
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Term
| Secondary remodeling process |
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Definition
| Cutting cone by osteoclasts, closing cone by osteoblasts; concentric ring deposited from outside edge towards center; BV and nerves enter to form Haversian canal |
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Term
| Secondary remodeling in cancellous bone |
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Definition
| Only occurs at trabeculae surface; no Haversian canals, osteoclast and osteoblast activity at the same location |
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Term
| Factors that increase osteoclast activity |
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Definition
| PTH, Thyroid hormone, glucocorticoids |
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Term
| Factors that decrease osteoclast activity |
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Definition
| Osteoprotegerin, Estrogen, Calcitonin |
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Term
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Definition
| Causes osteoblasts to stimulate maturation of osteoclasts by release of M-CSF and RANK ligand (RANKL) |
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Term
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Definition
| RANK ligand secreted by osteoblast, interacts with RANK receptor on osteoclast to stimulate differentiation and maturation |
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Term
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Definition
| Osteoblast release osteoprotegerin (OPG), binds RANKL to prevent interaction with RANK receptor, "decoy", decrease osteoclast differentiation |
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Term
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Definition
| Increase osteoblast production of OPG, prolong life of osteoblast |
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Term
| Calcitonin (secondary remodeling) |
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Definition
| Directly inhibit osteoblast activity; made by parafollicular cells of thyroid gland |
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Term
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Definition
| Necessary for bone mineralization |
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Term
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Definition
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Term
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Definition
| Increase osteoclastic resorption if levels too high |
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Term
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Definition
| Increase bone resorption, increase bone formation |
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Term
| Bone aging and osteoporosis |
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Definition
| Abnormal coupling of resorption and deposition in secondary remodeling; sensitive to hormonal levels (reduced estrogen after menopause); can be too much resorption leading to weak, porous bones; increased mineralization (brittle) |
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Term
| Fracture repair phases (4) |
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Definition
Inflammation, Soft Callus, Hard Callus, Secondary Callus (Callus reduction)
Fracture repair same independent of cause unless non-union |
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Term
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Definition
Closed, open (protrude through surface), comminuted (several pieces), greenstick (bone bows, not completely disrupted)
Closed heals fastest, break often incomplete in children (greenstick) |
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Term
| Fracture repair: Inflammation |
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Definition
| BVs rupture throughout, blood flows into fracture forming hematoma which coagulates and stabilizes; osteogenic response due to periosteum disruption; first 4 days, overlap with soft callus stage |
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Term
| Fracture repair: Soft Callus Stage |
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Definition
| Blood clot permeated with fibrous CT and cartilage, repair cells; clot becomes fibrous temporary callus to tie bone fragments together; bone vessels regrow, both types of ossification occur for 3-4 weeks |
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Term
| Fracture repair: Hard Callus Formation (Primary Callus) |
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Definition
| Woven bony callus; formed by intramembranous ossification (external callus-osteoblasts differentiate at perichondrum) and endochondrial ossification (internal callus); ~6 weeks to form, noticeable years later; BV supplying callus allow osteoclasts to enter and resorb dead bone fragments; 2-3 months until bony union forms |
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Term
| Fracture repair: Secondary Callus (callus reduction) |
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Definition
| Woven bone becomes lamellar by intracortical remodeling with osteons forming; remove excess bone from exterior of periosteal collar, restore medullary cavity; healing time average is 1+ year depending on many factors |
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