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Muscle Physiology and Anatomy. “The Last Chapter”!. ASSIGNMENT. Read Pages 7:152-170 Answer: Content Review – page 191 Questions: 1-11 . “Gross” Anatomy Requirements. Identify 20 Major Muscles For Exam: Know 3 Muscles (of the 20 major muscles)
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Muscle Physiology and Anatomy “The Last Chapter”!
ASSIGNMENT • Read Pages 7:152-170 • Answer: Content Review – page 191 • Questions: 1-11
“Gross” Anatomy Requirements • Identify 20 Major Muscles • For Exam: Know 3 Muscles (of the 20 major muscles) Origin: Most stable attachment Insertion: Most mobile attachment Action: What movement(s) Exercise specific for that muscle
Example: • Biceps Brachii (p. 181): • Origin:Scapula, Superior to glenoid fossa, and coracoid process • Insertion: Radial Tuberosity • Action:Flex and supinate arm and forearm • Exercise:Curls
Other “Gross” Terms • Prime Mover: The major muscle in a movement • Synergist: “Helpers” • Antagonists: “Opposers” • Fixators: Stabilizing the proximal joint
Functions: Muscular System • Movement • Posture • Respiration • Circulation • Produce Heat • Communication
Characteristics of Skeletal Muscle Tissue • Contractility: Shorten with force • Excitability: Respond to stimulus • Extensibility: Limited stretch”ability” • Elasticity: Recoil to resting length
Three Types of Muscle Tissue • Smooth: Found in walls of hollow organs, blood vessels and glands • Cardiac: Heart muscle • Skeletal: Attached to bone • Compared by striations, shape, control, nuclei and function
Striations: “Stripes” • Skeletal: YES • Smooth: NO • Cardiac: YES
Skeletal: Long cylinder “fiber” Smooth: “spindle shape” Cardiac: Branched Multiple, peripheral Single, central Single, central Shape and Nucleus
Control and Autorhythmicity • Skeletal: Voluntary- NO • Smooth: Involuntary- YES • Cardiac: Involuntary-YES
Muscle Structure • Connective Tissue: Epimysium (Fascia) wraps muscle, Perimysiumwraps fascicles, and endomysium wraps muscle fibers • Bundles of Bundles: Muscle ->fascicles->fibers->myofibrils-> myofilaments
Muscle Cell (Fiber) Structure • Sarcomeres:The real contractile elements of muscle cells • Myofilaments: Thick (myosin) and Thin (actin, troponin, tropomyosin) overlap to create the “striations” visible in the microscope
Muscle Cell Structure • Nuclei: Multiple (many fused cells), peripheral • Mitochondria: Many, near sarcomeres • Transverse Tubules, Terminal Cisternae:Internal extension of cell membrane – Action Potential transmission
Excitable Tissues • Nervous and Muscular • Respond to stimulus - transmitting electrical signal • Special quality of membrane proteins: pumps and channels
Resting Potential • Outside is More Positive than Inside • K+: Inside > Outside • Na+: Out > In
Excitable Cells: It’s All About Membranes! • Membrane channels and Pumps keep Na+ OUT: • This makes the inside RELATIVELY Negative: • Resting (waiting) Membrane Potential Resting Membrane Potential = -70 mV
Depoloarization • Rapid Charge reversal when stimulated • Na+ channels open - flooding inside with Na+ • K+ channels close
Depolarization Membrane Potential (inside) Na+ Channels Open 0 mV TH Threshold voltage -65 RMP Time: msec
Repolarization • Na+ Channels close • K+ channels reopen • Charge separation returns to resting values: Na+/K+ Pumps “kick out” leaking Na+ • Inside becomes negative again
Repolarization Na channels CLOSE K channels OPEN K moves OUT mV Time
Action Potential FACTS: • All or None Principle • Refractory Period: During “recovery” from AP, cell cannot be re-stimulated • Conduction along membrane is like “dominos” • Entire Cell Depolarizes
Action Potential • The “Domino Effect” of depolarization along an entire cell membrane • Includes Depolarization and Repolarization to reestablish the Resting Potential
And Now: “Interactive Physiology Muscle Cell Anatomy
Have a Nice Week! Quiz on Tuesday