Types and Characteristics of Muscle Tissue (p.394)

1. Universal characteristics of muscle
   a.  Excitability
   b.  Contractility
   c.  Extensibility
   d.  Elasticity
   
2. Unique properties of skeletal muscle
   
3. Series-elastic components
   a.  Connective tissue components
   b.  Functions
   

Microscopic Anatomy of Skeletal Muscle (pp.395-398)

1. The muscle fiber
   a.  Sarcolemma and T tubules
   b.  Nuclei
   c.  Myofibrils and myofilaments
   d.  Sarcoplasmic reticulum (SR)
   e.  Glycogen and myoglobin
   
2. Myofilaments
   a.  Thick filaments and myosin
   b.  Thin filaments
   
   • F actin and G actin
   • Tropomyosin
   • Troponin I, T, and C
   c.  Striations
   
   • Due to arrangement of myofilaments
   • Sarcomeres

Muscle Innervation and Membrane Potentials (pp.398-404)

1. Somatic motor neurons
   
2. The motor unit
   a.  One motor neuron and all muscle fibers innervated by it
   b.  Relationship to strength and control
   c.  Compensation for fatigue
   
3. The neuromuscular junction
   a.  Structures of the nerve fiber
   
   • Synaptic knob
   • Synaptic vesicles containing acetylcholine (ACh)
   • Active zones
   b.  Structures of the muscle fiber
   
   • Motor end plate
   • Junctional folds containing ACh receptors
   c.  Other structures
   
   • Synaptic cleft
   • Schwann cell
   • Basement membrane containing acetylcholinesterase
4. Membrane potentials
   a.  Concept of electrical potential
   b.  Resting membrane potential (RMP)
   
   • Diffusion of K⁺ out of cell
   • Retention of organic anions in cell
   • Electrostatic attraction of K⁺ into cell
   • Diffusion of Na⁺ into cell
   • Role of Na⁺-K⁺ pump
   c.  Action potentials
   

Contraction and Relaxation of Skeletal Muscle Fibers (pp.404-410)

1. Excitation
   a.  ACh release by motor nerve ending
   b.  Binding of ACh to receptor sites
   c.  End-plate potential (EPP) of muscle fiber
   d.  Action potential of muscle fiber
   
2. Excitation-contraction coupling
   a.  Stimulation of terminal cisternae
   b.  Release of calcium ions
   c.  Binding of Ca²⁺ by troponin C
   d.  Movement of tropomyosin away from active sites of actin
   
3. Contraction (sliding filament theory)
   a.  Activation and "cocking" of myosin head
   b.  Formation of myosin-actin cross bridges
   c.  Power stroke
   d.  Binding and hydrolysis of ATP by myosin head
   e.  Recovery stroke
   
4. Relaxation
   a.  Cessation of nerve signal
   b.  Degradation of ACh
   c.  Reabsorption of Ca²⁺ by sarcoplasmic reticulum
   d.  Blocking of active sites by tropomyosin
   e.  Stretching of muscle by series-elastic components and antagonists
   
5. Length-tension relationship and tonus
   a.  Resting length and contraction strength
   b.  Muscle tone
   

Behavior of Whole Muscles (pp.410-413)

1. Threshold
   
2. Latent period
   
3. Twitch
   a.  Contraction phase
   b.  Relaxation phase
   
4. Graded and all-or-none responses
   a.  All-or-none reaction of muscle fibers
   b.  Graded contractions of whole muscle
   
5. Treppe
   a.  Theories of mechanism
   b.  Relevance to warm-up exercises
   
6. Refractory period
   
7. Temporal (wave) summation
   
8. Tetanus
   
9. Isometric and isotonic contraction
   
10. Concentric and eccentric contraction
    

Muscle Metabolism (pp.413-417)

1. Energy transfer
   a.  Review of aerobic respiration and anaerobic fermentation
   b.  Immediate energy from the phosphagen system
   
   • Myokinase catalyzes ADP + ADP -> AMP + ATP
   • Creatine kinase catalyzes CP + ADP -> creatine + ATP
   c.  Short-term energy from the glycogen-lactic acid system
   d.  Long-term energy from aerobic respiration
   
2. Fatigue and endurance
   a.  Causes of fatigue
   b.  Maximal oxygen uptake (^Vo₂ max)
   
3. Oxygen debt
   a.  Replacing oxygen reserves
   b.  Replenishing phosphagen system
   c.  Oxidizing lactic acid
   d.  Serving elevated metabolic rate
   
4. Metabolic classes of muscle fibers
   a.  Slow-twitch fibers
   
   • Twitches up to 100 msec
   • Adaptations for aerobic respiration
   • Resistance to fatigue
   • Important in posture and endurance exercises
   b.  Fast-twitch fibers
   
   • Twitches as brief as 7.5 msec
   • Adaptations for anaerobic energy transfer
   • Quick release and reuptake of Ca²⁺
   • Susceptibility to fatigue
   • Important in sports with quick stop-and-go action
   c.  Relationship to synergistic muscle groups
   d.  Intermediate fibers
   e.  Red and white muscles
   f.  Heredity and muscle composition
   
5. Muscular strength
   a.  Muscle size (cross-sectional area)
   b.  Fascicle arrangement
   c.  Size of active motor units
   d.  Multiple motor unit summation
   e.  Temporal summation
   f.  Length-tension relationship
   g.  Fatigue
   
6. Muscular conditioning and atrophy
   a.  Effects of resistance exercises
   b.  Effects of endurance exercises
   c.  Muscle atrophy
   
7. Delayed onset muscle soreness
   
8. Cramps
   

Smooth Muscle (pp.418-422)

1. Types and functions
   a.  Multiunit smooth muscle
   
   • Locations (relatively limited)
   • Innervation similar to skeletal muscle
   • Independent contraction of fibers
   b.  Single-unit smooth muscle
   
   • Locations (more widespread, visceral)
   • Innervation
   • Cells coupled by gap junctions
2. Microscopic anatomy
   a.  Fusiform uninucleate cells
   b.  Dense bodies instead of Z discs
   c.  Lack of T tubules and sarcomeres
   d.  Scanty SR; calcium obtained primarily from ECF
   
3. Innervation and stimulation
   a.  Autonomic nervous system
   
   • Sympathetic and parasympathetic divisions
   • Dual innervation
   b.  Varicosities and diffuse junctions (synapses en passant)
   c.  Neurotransmitters and receptors
   
   • Acetylcholine and norepinephrine
   • Excitatory and inhibitory junction potentials
   • Role of receptor types in excitation and inhibition
   d.Graded responses
   
4. Gap junctions and pacemakers
   
5. Contraction and relaxation
   a.  Influx of Ca²⁺ from the ECF
   b.  Binding of Ca²⁺ to calmodulin
   c.  Action of myosin light-chain kinase
   d.  Power and recovery strokes similar to skeletal muscle
   e.  Long latent period and slow contraction
   f.  Latch-bridge mechanism and smooth muscle tone
   
6. Response to stretch
   a.  Stress-relaxation response
   b.  Lack of length-tension relationship
   c.  Plasticity
   

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