PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18MUSCLE.I. Types of muscle:A. Striated muscle.http://www.ttuhsc.edu/courses/cbb/histo/muscle/pg08jp.htmlhttp://cal.vet.upenn.edu/histo/muscle/skeletal.html1. Skeletal muscle - voluntary muscle2. Cardiac muscle - heart muscleII. Basic components of muscle cell organizationA. sarcolemma - plasmalemma of muscle cells - well developed basement membrane. Sarcolemmal tubular invaginations called transverse tubules - associated with the sarcoplasmic reticulum. B. sarcoplasm - cytoplasm of muscle cells excluding the myofibrils.C. sarcoplasmic reticulum - smooth endoplasmic reticulum of muscle cells.D. sarcomere - basic contractile unit of a myofilament/myofibril (skeletal and cardiac muscle only)F. myofibril or myofilament - a string of sarcomeres (skeletal and cardiac muscle only)G. myofiber - a single muscle cellE. sarcosome - specialized long mitochondrion found (skeletal and cardiac muscle only).H. epimysium - thick layer of collagenous connective tissue that surrounds large bundles of muscle.II. Basic components of muscle cell organizationJ. fascicle - bundle of muscle cells (myofibers) bounded by perimysium.I. perimysium - collagenous connective tissue continuous with epimysium that separates fascicles of muscle cells.K. endomysium - very thin layer of connective tissue that separates individual muscle cells.http://training.seer.cancer.gov/module_anatomy/unit4_2_muscle_structure.htmlfascicleperimysiumIII. Skeletal - voluntary musclehttp://www.finchcms.edu/anatomy/histology/histology/muscle/h_m_8.htmB. Skeletal muscle is connected to bone a tendon.A. As just described, epimysium, perimysium, and endomysium surrounds the components of skeletal muscle as.http://www.siumed.edu/~dking2/ssb/NM016b.htmC. Individual muscle cells are syncytial (multinucleate). Nuclei at periphery of cell.D. Each individual muscle cell is called a muscle fiber/myofiber. Within the sarcoplasm of these cells are numerous myofilaments/myofibrils.E. The myofilaments/myofibrils are linear arrays of structures known as sarcomeres - connected in end to end repeating pattern. The sarcomeres contain filaments of actin and myosin that interact to cause contraction of the muscle cells. Skeletal/voluntary muscleIII. Skeletal - voluntary musclehttp://www.siumed.edu/~dking2/ssb/muscle.htmIII. Skeletal - voluntary muscleF. Axons from CNS form multiple synapses on sarcolemma. http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab10/Examples/exmtrplt.htmhttp://www.gwc.maricopa.edu/class/bio201/histo/nmj.htm• Called myoneural junctions, neuromuscular junctions, or motor endplates. • Contain synaptic vesicles filled with acetylcholine. • Nervous impulses (action potentials) cause acetylcholine in vesicles to be released into the gap between the axon and the muscle cell • This initiates an electric action potential in the sarcolemma that causes the muscle to contract.III. Skeletal - voluntary muscleA = Artefact; Ec = Euchromatin; Hc = Heterochromatin; H = Herzmuskelzelle; Ko = Kollagenfasern (Querschnitt); Ma = Macula adherens;Mi = Mitochondrium (Crista-Typ); Nf = Neurofilamente; Nt = Neurotubuli; P = Plasmalemm;Po = postsynaptische Membran; Pr = praesynaptische Membran; S = synaptischer Spalt; SR = sarcoplasmatisches Reticulum;SV = synaptische Vesikel;TB = terminaler Bouton (= motorische Endplatte, enthält Axolemma).Electron micrograph of motor endplate synapsehttp://www.uni-mainz.de/FB/Medizin/Anatomie/workshop/EM/externes/Wartenberg/nmendpl1.htmlG. Sarcoplasmic reticulum - stores calcium that is released to cause contraction.1. Organization - extensions of the sarcolemma called Transverse tubules (T-tubules) extend between parallel cisternae of the sarcoplasmic reticulum that encircle individual myofilaments (myofibrils).2. Allows very rapid transmission of surface action potentials to the interior of the cell ----> releasing calcium ions from the sarcoplasmic reticulum and allowing the sarcomeres of the myofilaments to all contract at essentially the same time.V. Cardiac muscleA. Unlike striated muscle, cardiac muscle cells are not a syncytium for most part, though some cells may have two nuclei.http://www.finchcms.edu/anatomy/histology/histology/muscle/h_m_13.htmlB. The structure is similar to that of striated skeletal muscle - myofilaments (myofibrils) composed of sarcomeres are present. Contraction is mediated by release of Ca+2 from sarcoplasmic reticulum. Fewer T-tubules.http://www.cytochemistry.net/cell-biology/medical/practice_practical_muscle.htmC. Cardiac muscle differs from skeletal muscle in four major ways,V. Cardiac muscle1. cardiac muscle cells are branched and4. muscle cells held together by intercalated disks.2. have 1-2 nuclei per cell3. nucleus located in center of cell in cross-sectionshttp://www.siumed.edu/~dking2/crr/cvguide.htm#hearta. Interdigitating regions of the sarcolemma of adjacent cardiac muscle cells that b. Hold the cells together c. Act to conduct ionic changes between cells. d. The intercalated disks form the irregular, jagged, dark lines that are characteristic of stained cardiac muscle.Intercalated disks:2. The intercalated disk is composed of a number of structures that are organized along adjacent muscle cell sarcolemmas in a repeating array,a. Macula adherens (desmosomes) - previously described structures that hold cells together. Located between adjacent myofibers.b. zonula adherens - Located where myofilaments end at muscle cell sarcolemma.c. gap junctions - allow transfer of ions between muscle cells. Allows cells to coordinate their activities. Action potentials can spread quickly between the sarcoplasmic reticula of adjacent cardiac muscle cells via gap junctions.V. Cardiac muscleD. The sarcoplasmic reticulum of cardiac muscle cells is not as regular as that of skeletal/voluntary muscle.V. Cardiac muscleE. Purkinje fibers - modified cardiac muscle cells found in the ventricle that are specialized for conduction of electrical impulses. Conduct the contraction impulses that originate in the sinoatrial node (then passed via atrioventricular node) to the cardiac muscle fibers.VI. Smooth muscleA. This sort of muscle consists of long, overlapping, spindle shaped cells that look similar to fibroblasts.B. Smooth muscle cells similarity to fibroblasts is evident in that they are able to synthesize collagen, elastin, and