Histology - Muscle Tissues

degrades ACh in synaptic cleft.

a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane.

dervied from mesoderm, striated, capilaries in intercellular spaces. Slow and fast fiber types.

aggregate at top of junctional folds

associated with sweat glands, contain both actin and myosin. contraction mechanism similar to smooth muscle cells, but ectoderm derived.

Contains the entire length of a single thick filament.

Dense bodies (where actin attatches) instead of Z disks as in skeletal muscle; have noncontractile intermediate filaments (along w/dense bodies, form intracellular cytoskeleton); has slower contraction speed than skeletal.

calcium interacts with calmodulin, causing interaction between actin and myosin

presynaptic element

cylinder-shaped, paralell, multinucleated, periferal nuclei. Mitochondria and myoglobin in high quantity.

great capacity for hyperplasia and hypertrophy, (ex: uterus in pregnancy)

fast glycolitic muscle fibers, anaerobic respiration.

type III collagen are located external to the basal lamina. Hugh compnent of endomesium fround smooth muscle.

calcium storage and release

Purkinje fibers

receptors on t-tubule and SR interact to release calcium

On perfery of muscle fibers, can undergo hyperplasia (mitosis) and hypertrophy by fusing with other skeletal muscles.

is the zone of thin filaments that is not superimposed by thick filaments.

Autoimmune disorder. Autoantibodies bind acetylcholine receptors in skeletal muscle, causing muscle weakness and potential death. Treatment includes AChE inhibitors

branched, layered, mononucleated, central nucleus. Intercalcated discs with gap junctions, high mitochondria and myoglobin. diad at the Z disc.

enzyme that aids in active calcium reuptake by SR after contraction.

A paler region within the A-band, zone of the thick filaments that is not superimposed by the thin filaments.

Stain dark and lie just inside sarcolema. Interaction between them and reticular fibers that harnesses the force of contraction of the myofilaments, like wringining a sponge, Causes “corkscrew nucleus”.

Autonomic nervous system, Purkinje fibers (modified cardiac muscle cells), gap junctions.

indentations in surface of sarcolemma, may act like T tubules and sarcoplasmic reticulum of skeletal muscle

a layer of connective tissue, which ensheaths the entire muscle. dense irregular connective tissue, continuous with fascia.

derived from mesoderm, striated, rich capillary beds in intracellular connective tissue, located in proximal portion of heart and pulmonary vessels.

a wispy layer of areolar connective tissue that ensheaths each individual muscle fiber. It also contains capillaries andnerves. It overlies the muscle fiber's cell membrane: thesarcolemma.

(from the German "Mittelscheibe", the disc in the middle of the sarcomere) formed of cross-connecting elements of the cytoskeleton.

anchors thin myofilaments to Z disc.

two chains of F-actin, tropomyosin and troponin associate. Ca2+ causes conformational change.

two Z discs are brought closer together as myofilaments slide past each other.

Dystrophin or sarcolemma molecules absent or reduced causing muscle weakness and potential death. Treatment controls symptoms to maximize quality of life.

fusiform-shaped, often in perpendicular layers, surrounded by basal lamina.

new myofibrils form to increase fiber diameter

200-300 myosin molecules, 2 heavy and 2 light chains per myosin.

Ca2+ required to initiate contractions, binds to calmodulin (no troponin is smooth muscle) which regulates myosin kinase (transfers P+ group from ATP to light myosin on heads), cross-bridging occurs(enzymes are slower than skeletal, so slower formation)

Occurs following death because the lack of ATP preventing the dissassociation of actin and myosin. ATP important for relaxing muscle, dissociation of thin and thick myofilaments.

prominent in wound contraction and tooth eruption deriving from connective tisues.

lower motor neuron (LMN) + muscle fibers

They connect heart muscle cells, allowing them to work as a single functional organ. Have lateral and transverse portions. Lateral has gap junctions, and faces less stress in contraction. Transverse region contains adherens junctions.

Functional units of muscle fiber. Defined by Z lines.

anchors thick myofilaments to Z discs

triad of structures at A-I junction, t-tubule, terminal cisternal of SR.

monitors length and changes in length of muscle, and participates in stretch reflexes. In OMM, an important target for effective treatment, i.e. counter-strain technique.

slow oxidative muscle fibers, aerobic respiration

indicating the contracted state of the cell

a sheath ofconnective tissue that groupsmuscle fibers into bundles (anywhere between 10 to 100 or more) or fascicles.

mononucleate, central nucleus
no striations or sarcomeres
no t-tubules, but have caveolae
involuntary control by ANS

Interferes with the release of acetylcholine from LMN causing muscle paralysis and potential death. Treatment can include an anti-toxin.

derived from mesoderm (and ectoderm), no striations, loacted in walls of hollow viscera, blood vessels, glands, dermis.

Skeletal Muscle regulation of contraction

Cardiac muscle regulation of contraction

Smooth muscle regulation of contraction

Muscle spindle function

T-Tubule Structure and Function

Transverse Portion of Intercalcated Disc

Lateral Portion of Intercalcated Disc

triad

Terminal Cisternae

Contraction mechanism of smooth muscle - detailed