Lecture 3: Organization of Muscle, Motor Unit, Nerve Types Flashcards
Put in order of largest to smallest unit of organization
Muscle fiber, Muscle fascicle, Sarcomere, Myofibril, Skeletal muscle
Skeletal muscle > muscle fascicle > muscle fiber > myofibril > sarcomere
Provide correct relationship of structure - contains:
A. Skeletal muscle - muscle fibers
B. Muscle fascicle - Sarcomeres
C. Muscle fiber - Thin and thick filaments
D. Myofibril - muscle fascicles
E. Sarcomere - myofibrils
A. Skeletal muscle - muscle fascicles B. Muscle fascicle - muscle fibers C. Muscle fiber - myofibrils D. Myofibril - sarcomeres E. Sarcomere - thin and thick filaments
Provide correct relationship of structure - surrounded by:
A. Skeletal muscle - Endomysium
B. Muscle fascicle - Sarcoplasmic reticulum
C. Muscle fiber - Epimysium
D. Myofibril - Perimysium
A. Skeletal muscle - Epimysium
B. Muscle fascicle - Perimysium
C. Muscle fiber - Endomysium
D. Myofibril - Sarcoplasmic reticulum
Site where axon and muscle fiber communicate
Neuromuscular junction
Five basic components of a neuromuscular junction
- motor neuron
- motor end plate
- synaptic cleft
- synaptic vesicles
- neurotransmitters
Muscle contraction involves:
Motor nerve impulses cause release of A. _______ from B._______ which bind to receptors on the C. ________ and generate muscle contraction.
A. acetylcholine
B. synaptic vesicles
C. motor end plate
Muscle relaxation involves:
A. _______ breaks down acetylcholine. B. ______ impulses stop. C. ______ moves back into sarcoplasmic reticulum preventing D. _______ and _______ from binding.
A. acetylcholinesterase
B. motor neuron
C. calcium
D. myosin and actin
A single motor neuron and all the muscle fibers it controls. Functional connection between muscular & nervous systems.
Motor unit
T or F: Motor Unit
A.
B. When motor unit fires, individual fibers can contract separately
C. 1 neuron may innervate several muscle fibers
D. 1 muscle fiber may be innerv. by only 1 motor neuron
A. True
B. False. All fibers contract together
C. True
D. False. Muscle fiber may be innvervated by several motor neurons
How are fine control and strength control governed in muscle fibers?
One neuron may innervate several muscle fibers. One muscle fiber may be innervated by several motor neurons. This creates both large and small motor units for fine control and strength control. One muscle fiber may act with several motor units depending on demand.
Twitch, Treppe, Summation, or Tetanus?
A. Occurs with low frequency stimuli (
A. Twitch
B. Treppe
C. Wave summation
Twitch, Treppe, Summation, or Tetanus?
A. Reach peak tension
B. Each stimulus arrives before previous twitch is over
C. Relaxation complete before next stimulus occurs
D. Each stimulus produces identical response
A. Tetanus
B. Wave summation
C. Treppe
D. Twitch
Twitch, Treppe, Summation, or Tetanus?
A. Each contraction is a little stronger than previous
B. Can be complete or incomplete
C. Single brief stimulus produces quick cycle of contraction/relaxation that lasts muscle twitches fuse
A. Treppe or wave summation
B. Tetanus
C. Twitch
D. Wave summation
Tentanus: Complete or Incomplete?
A. No relaxation bet. contractions; sustained contraction
B. Occurs with max freq. stimulation = 20-40 stimuli/sec
C. Occurs with max freq. stimulation = 40-50+ stimuli/sec
D. Muscle fibers partially relax between contractions
E. Produces peak tension
A. Complete B. Incomplete C. Complete D. Incomplete E. Both can
Nerve Types: Sensory, Motor or Interneuron?
A. Efferent; impulses from CNS to muscles/glands/organs
B. Transmit impulses from one neuron to another
C. Afferent; impulses from receptors to CNS
A. Motor
B. Interneuron
C. Sensory
Nerve Fibers: A, B, or C fibers?
A. Unmyelinated, slower, smallest diameter, sense pain
B. Myelinated, slower
C. Myelinated, range from slow to fast; largest diameter
D. Includes alpha, beta, gamma, and delta types
A. C fibers
B. B fibers
C. A fibers
D. A fibers
Types of A fibers: Alpha, Beta, Gamma, or Delta?
A. Motor efferent to muscle spindle fiber; muscle tone
B. Myelinated, thick, fastest conducting; motor efferents
C. Skin temp and pain; nociceptive
D. Myelinated, thick; touch/pressure afferents; mechanoreceptors
A. Gamma
B. Alpha
C. Delta
D. Beta
T or F: Spinal Reflex Arc
A. Voluntary reaction
B. Sensory receptor –> effector organ –> interneuron
C. Sensory neuron –> sensory receptor –> effector organ
D. Sensory neuron –> interneuron –> motor neuron
A. False. Automatic response to stimulus without thought
B. False
C. False
D. True
Proprioceptors: Muscle spindle, Golgi tendon, or Joint kinesthetic?
A. Located within muscle belly (intrafusal)
B. Located within tendon (extrafusal)
C. Located in and around synovial joint capsule
A. muscle spindle
B. Golgi tendon
C. joint kinesthetic
Proprioceptors: Muscle spindle, Golgi tendon, or Joint kinesthetic?
A. Detects force of muscle contraction, tendon tension
B. Detects rate of muscle stretch & muscle length
C. Detects direction of movement, accel/decel, pressure, excess strain, postural changes
D. Reflexively inhibits agonist at end range of joint motion
A. Golgi tendon
B. Muscle spindle
C. Joint kinesthetic
D. Golgi tendon
Proprioceptors: Muscle spindle, Golgi tendon, or Joint kinesthetic?
A. Sensory and motor innervation
B. Inhibits synergists; facilitates antagonist
C. Involuntary muscle relaxation
D. Involuntary muscle contraction
A. Muscle spindle
B. Golgi tendon
C. Golgi tendon. reduces tension on tendons
D. Muscle spindle
Muscle Spindle Intrafusal fibers: Nuclear Bag or Chain?
A. Concentrated in the central part of the fiber
B. Sensitive to steady changes of length of muscle
C. Input from gamma motor neurons; produces tension
D. Sensitive to sudden rate of change in muscle length
A. Bag
B. Chain
C. Bag
D. Bag
Muscle Spindle Recptrs: Primary or Secondary endings
A. Wraps arnd central noncontractile area of bag/chain
B. Associated with type 1a fiber
C. Associated with type II fiber
D. Send sensory input to CNS re: spindle length
A. Both
B. Primary
C. Secondary
D. Both
Muscle Spindle Recptrs: Primary or Secondary endings
A. Respond to overall length of muscle fiber
B. Respond to rate of change in muscle fiber length
C. Smaller diameter; slower
D. Larger diameter; faster
A. Secondary
B. Primary
C. Secondary
D. Primary
What are intrafusal and extrafusal fibers? Describe their relationship.
Intrafusal = in capsule w/in extrafusal
Extrafusal = voluntary skeletal muscle fibers.
Intrafusal fibers wrapped by type Ia and II sensory neurons that send input to CNS. Ends of intrafusal fibers attach to extrafusal fibers and receive input from gamma motor neurons to contract and to pull on spindle.
T or F? Muscle Spindle Receptors: Golgi Tendon
A. Sensory innervation only
B. Incr. tendon tension stimulates type II sensory neurons
C. Sensitive to intense stretch and slow stretch
D. Inhibits alpha neurons to relax muscle/protect tendon
A. True
B. False. Type 1b
C. False. Only intense stretch
D. True
Joint Kinesthetic Receptors: Pacinian, Ruffini, or Free?
A. Located in CT and synovial joint capsules
B. Located in most body tissues
C. Located in synovial capsules and ligaments
A. Pacinian corpuscles
B. Free nerve endings
C. Ruffini corpuscles
Joint Kinesthetic Receptors: Pacinian, Ruffini, or Free?
A. Detects lateral stretch, changes in joint angles
B. Respond to rapid and sustained pressure
C. Respond to rapid pressure change, stretch, accel/decel of joint movement
A. Ruffini corpuscles
B. Free nerve endings and Ruffini (responds to DEEP … pressure)
C. Pacinian corpuscles
Reflexes: Quick Stretch, Reciprocal, or Autogenic?
A. Detects stretch in muscle spindles
B. Detects stretch in Golgi tendon organs
C. Guards against potential injury to muscle
D. Guards against potential injury to tendon
A. Quick stretch reflex and Reciprocal Inhibition
B. Autogenic Inhibition
C. Quick stretch reflex and Autogenic Inhibition
D. Autogenic Inhibition
Reflexes: Quick Stretch, Reciprocal, or Autogenic?
A. Inhibitory interneuron relaxes antagonist
B. Alpha motor neuron stimulates antagonist
C. 1b afferent; Inhibitory interneuron relaxes agonist; excitatory interneuron contracts antagonist
D. Respond to rapid and sustained pressure
A. Reciprocal Inhibition
B. Quick stretch reflex
C. Autogenic Inhibition
D. Quick stretch reflex
Name three NMT techniques that are based on spinal arc reflexes?
Post-isometric relaxation
Muscle energy technique
Strain-counterstrain
Part of a routine orthopedic and neurological examination to test the integrity of the components of the simple reflex arc. Helps determine if there is a lower or upper motor neuron lesion.
DTR - deep tendon reflex