VPHY EXAM 2 - MUSCLE PHYSIOLOGY QUESTIONS AND ANSWERS SOLVED CORRECTLY
what controls the skeletal muscles? - Answers somatic motor system
3 muscle types - Answers - smooth
- cardiac
- skeletal
5 categories of skeletal muscle function - Answers - movement
- support
- posture
- temperature regulation
- communication
the two parts of myofilaments - Answers - myosin
- actin
what gives the skeletal muscle its rod appearance? - Answers myocyte/muscle cell
what gives the skeletal muscle its striped appearance? - Answers myofilament parts
motor unit - Answers a single motor neuron and all of the muscle cells (fibers) it innervates
how many muscle cells does a typical motor neuron innervate? - Answers 100-1000 muscle cells!
a muscle is comprised of one or many motor unit(s) - Answers many
are all muscle fibers in the same motor unit the same or different type? - Answers same type!
NMJ (neuromuscular junction) - Answers specialized synapse between the somatic motor neuron's
nerve terminal and the motor end plate of the skeletal muscle cell
what sends the signal in the neuromuscular junction - Answers somatic (alpha) motor neuron
what recieves the signal in the neuromuscular junction - Answers skeletal muscle cell
E/C coupling - Answers - excitation/contraction coupling
- transformation of the electrical signal in the muscle cell into contraction of sarcomeres
what kind of receptors are on the motor end plate in the neuromuscular junction? - Answers nicotinic
, 9 steps from motor neuron APs to skeletal muscle contractions - Answers 1. ACh binds to skeletal muscle
fiber
2. AP moves into T-tubules
3. sarcoplasmic reticulum releases Ca2+
4. Ca2+ binds troponin; active cross-bridge cycling
5. skeletal muscle contraction
6. acetylcholinesterase degrades ACh
7. Ca2+ pumped into ECF and SR
8. tropomyosin blocks cross-bridge formation
9. skeletal muscle contraction is pervented
the firing of motor neuron's AP leads to - Answers contraction of muscle cell
what causes muscle contraction - Answers the Ca2+ release from the SR after Muscle APs are sensed in
the T-tubules
parts of the sarcolemma - Answers - t (transverse)-tubules invaginate the myofibrils
- t0tubules are continuous with the sarcolemma
sarcoplasmic reticulum surrounds - Answers myofibrils
what carries the AP does the T-tubules - Answers Na+ channels
what activates the Na+ channels in a muscle cell - Answers EPSP
are skeletal muscle cells long or short - Answers long
what are the sarcoplasmic reticulum calcium release channels called - Answers ryanodine receptors
(RyRs)
what are the transverse tubule voltage-gated calcium channel called - Answers dihydropridine receptors
(DHPRs)
what do the transverse tubule voltage-gated calcium channel do - Answers - act as voltage centers
- physically opens Ca2+ receptors
How does a larger motor unit differ from a smaller motor unit? - Answers a large motor unit innervates
many more muscle fibers
what controls the skeletal muscles? - Answers somatic motor system
3 muscle types - Answers - smooth
- cardiac
- skeletal
5 categories of skeletal muscle function - Answers - movement
- support
- posture
- temperature regulation
- communication
the two parts of myofilaments - Answers - myosin
- actin
what gives the skeletal muscle its rod appearance? - Answers myocyte/muscle cell
what gives the skeletal muscle its striped appearance? - Answers myofilament parts
motor unit - Answers a single motor neuron and all of the muscle cells (fibers) it innervates
how many muscle cells does a typical motor neuron innervate? - Answers 100-1000 muscle cells!
a muscle is comprised of one or many motor unit(s) - Answers many
are all muscle fibers in the same motor unit the same or different type? - Answers same type!
NMJ (neuromuscular junction) - Answers specialized synapse between the somatic motor neuron's
nerve terminal and the motor end plate of the skeletal muscle cell
what sends the signal in the neuromuscular junction - Answers somatic (alpha) motor neuron
what recieves the signal in the neuromuscular junction - Answers skeletal muscle cell
E/C coupling - Answers - excitation/contraction coupling
- transformation of the electrical signal in the muscle cell into contraction of sarcomeres
what kind of receptors are on the motor end plate in the neuromuscular junction? - Answers nicotinic
, 9 steps from motor neuron APs to skeletal muscle contractions - Answers 1. ACh binds to skeletal muscle
fiber
2. AP moves into T-tubules
3. sarcoplasmic reticulum releases Ca2+
4. Ca2+ binds troponin; active cross-bridge cycling
5. skeletal muscle contraction
6. acetylcholinesterase degrades ACh
7. Ca2+ pumped into ECF and SR
8. tropomyosin blocks cross-bridge formation
9. skeletal muscle contraction is pervented
the firing of motor neuron's AP leads to - Answers contraction of muscle cell
what causes muscle contraction - Answers the Ca2+ release from the SR after Muscle APs are sensed in
the T-tubules
parts of the sarcolemma - Answers - t (transverse)-tubules invaginate the myofibrils
- t0tubules are continuous with the sarcolemma
sarcoplasmic reticulum surrounds - Answers myofibrils
what carries the AP does the T-tubules - Answers Na+ channels
what activates the Na+ channels in a muscle cell - Answers EPSP
are skeletal muscle cells long or short - Answers long
what are the sarcoplasmic reticulum calcium release channels called - Answers ryanodine receptors
(RyRs)
what are the transverse tubule voltage-gated calcium channel called - Answers dihydropridine receptors
(DHPRs)
what do the transverse tubule voltage-gated calcium channel do - Answers - act as voltage centers
- physically opens Ca2+ receptors
How does a larger motor unit differ from a smaller motor unit? - Answers a large motor unit innervates
many more muscle fibers
