Muscular System Part 2 Flashcards
Treats back muscle spasms, uncontrolled blinking, wrinkles
Botox
Inhibits AChE, causes potentially fatal paralytic convulsions
Nerve gas and insecticides
Blocks ACh receptors, stops muscles from contracting
Curare, Cobra toxin
What are the 3 factors that determine how long a contraction will last?
Duration of neural stimulation, Number of calcium and ATP
What are 3 ways to increase tension of skeletal muscle fibers?
Changes sarcomere length, Stimulus frequency, motor unit recruitment
What does the number of pivoting cross-bridges depend on?
Amount of overlap between actin and myosin
Maximum ability to generate tension
Intermediate fiber resting length
When stimulation occurs immediately after the relaxation phase
Treppe
Stimulation occurs before relaxation is complete, when stimulus frequency is greater than duration of a single twitch
Wave summation and tetanus
Don’t reach maximum tension
Incomplete tetanus
Reach maximum tension
Complete tetanus
Single motor neuron and all of the muscle fibers it innervates
Motor unit
Increase in number of active motor units
Motor unit recruitment
What is recruitment controlled by?
Nervous system
What indicates how fine the control of movement will be in motor units?
Size
Contraction where tension rises until muscle length changes then remains constant
Isotonic contraction
What is an example of isotonic contraction?
walking, running, lifting an object
What are the 2 types of isotonic contractions?
Concentric and eccentric
Muscle tension overcomes load and muscle shortens
Concentric contraction
When load is more than peak tension produced, muscle lengthens
Eccentric contraction
Muscle length does not change and tension never exceeds load, contracting muscle bulges but not as much as during isotonic contraction
Isometric contraction
What is an example of isometric contraction
Postural muscle contraction
What are the 3 sources of ATP in muscles?
Glycolysis, aerobic respiration, creatine phosphate
Where does glycolysis occur in muscle? What is produced?
Sarcoplasm; 2 pyruvate and 2 ATP
Provides 95% of ATP demands of resting muscle cell; occurs in mitochondria
Aerobic respiration
Assembled from amino acids; facilitates regeneration of ATP
Creatine phosphate
Most glucose in muscle comes from stored ____
Glycogen
What provides most of the ATP at peak activity levels?
Glycolysis
What does excess pyruvate convert to?
Lactic acid
What are the effects of excess lactic acid?
Decrease pH and cause fatigue
Amount of oxygen needed to return to normal prexertion conditions
Oxygen debt
What are 3 types of muscle fibers?
Slow, fast, intermediate
Can muscle fibers be changed? If so, how?
Yes; training
Fatigue resistant, slow to contract, high levels of myoglobin, mitochondria, and blood capillaries
Slow fibers
What is an example of slow fibers?
Postural muscles of neck, back, and legs
Fatigable, contract quickly, large diameter, low levels of myoglobin, mitochondria, and blood capillaries
Fast fibers
What are some examples of fast fibers?
Eye muscles, muscles used for throwing and weightlifting
Where is white muscle found mostly in?
Fast fibers
Where is red muscle found mostly in?
Slow fibers
Fatigue resistant, fast to contract, mid-sized, high levels of myoglobin, mitochondria, and blood capillaries
Intermediate fibers
What can increase the effectiveness of each muscle type with proper training?
Sport specificity
What type of sport can increase fast fibers?
Fast intensive workouts
What type of workout can increase the number of slow fibers?
Slow, long workouts
Congenital diseases that produce progressive muscle weakness and deterioration
Muscular dystrophy
What is the most common type of muscular dystrophy?
Duchenne muscular dystrophy
Progressive muscular weakness due to loss of acetylcholine receptors at motor end plate; autoimmune disorder
Myasthenia gravis
