NUR 0012 Lecture 25 Ch. 9 Muscle Physiology: Functions, Features, and TypesOutline of Last LectureI. Ch. 10 muscular system cont.A. Shoulder muscles: axial, scapular, and rotator cuffsB. Arm muscles: anterior and posteriorC. Forearm muscles: flexors, extensors, pronators, supinator, and thumb movementsOutline of Current Lecture I. Ch. 9 muscular physiologyA. FunctionsB. FeaturesC. Types of muscle cells: skeletal, cardiac, smoothD. CT coverings help direct contractionE. Muscle cells are extremely vascular and innervatedF. Transverse tubulesCurrent LectureI. Ch. 9 muscular physiologyA. Functions1. Movements2. Posture3. Stabilizes joints4. Generates heatB. FeaturesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Contractility: active when contracted, muscle tissue shrinks2. Excitability3. Extensibility: can over stretch, can lead to muscle tear or strain4. ElasticityC. Types of muscle cells1. Skeletal: focusing more on this type for nowa. Cells are long thin cylinders, very neatly organized, multinucleated (so we can build lots of mitochondria), visibly striated (alternating patterns of contractile proteins), voluntary control1) Some work in automatic fashion like blinking or diaphragm2. Cardiac: short fat cells, uninucleated, have intercollated discs, cells interconnect with each other in multiple places, not as organized as skeletal, allows muscles to work simultaneously (chambers of heart pumping together), involuntary control, striated3. Smooth: fat in middle and tapered at end (fusiform), uninucleated, not striated, involuntary controlD. CT coverings help direct contraction and separate muscles into functional groups1. Epimysium2. Perimysium: wrap around a fascicle3. Endomysium: between individual muscle fibers4. Muscle fiber in middle of a fascicle 5. Each fascicle (bundle of muscle cells) has typically between 10-150 cells6. Some large muscles may have hundreds of fasciclesE. Each single skeletal muscle cell (myofibril) has at least one big nerve, it’s extremely innervated and vascular1. Sarcomere: smallest unit of a muscle cell that can change size2. Actin and myosin proteinsa. Thick filamentb. Thin filament c. Actins are double helix proteins, tropomyosin and troponin surround it (regulate when actin and myosin grab on to each other)3. H zone: actin and myosins don’t overlapF. Transverse tubules are invaginations of the sarcolemma surrounded by SR1. Conduct electrical signal causing release of
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