Ch 10: Animation: Neuromuscular Junctions 10.3 10.4
The sarcomere consists of all of the following except Troponin Myosin Actin The motor neuron
The motor neuron
Creatine phosphate provide enough additional energy to sustain muscle activity for
15 sec
A group of muscle cells stimulated by a single motor neuron is known as a 1. myofibril. 2. motor unit. 3. contractile structure. 4. neuron divergence.
2. motor unit.
The neurotransmitter released by the motor neuron to cause muscle contraction is 1.serotonin. 2.acetylcholine. 3.dopamine. 4.epinephrine.
2.acetylcholine.
Through aerobic respiration in the mitochondria, one glucose molecule can create
30 or more AtP
By what process does the motor neuron stimulate the muscle cell? 1. The motor neuron changes shape putting pressure on the muscle cell to trigger contraction. 2.The action potential skips directly from the motor neuron onto the muscle cell. 3. The motor neuron creates a magnetic resonance which stimulates myofibrils to react. 4. Neurotransmitter is released into the synaptic cleft to cause an action potential in the muscle cell.
4. Neurotransmitter is released into the synaptic cleft to cause an action potential in the muscle cell.
The impulses that initiate muscle contraction originates in the 1. muscle itself. 2. joint associated with the specific muscle. 3. tendons attached to the ends of the muscle. 4. brain or spinal cord.
4. brain or spinal cord.
Choose the correct sequence of events: Action potential reaches synapse—Acetylcholine is released by motor neuron—Calcium ions enter motor neuron—Sodium ions flood into the muscle cell—Acetylcholine binds to gated ion channels on sarcolemma, transferring the action potential. Action potential reaches synapse—Calcium ions enter motor neuron—Acetylcholine is released by motor neuron—Acetylcholine binds to gated ion channels on sarcolemma—Sodium ions flood into the muscle cell, transferring the action potential. Action potential reaches synapse—Acetylcholine is released by motor neuron—Acetylcholine binds to gated ion channels on sarcolemma—Calcium ions enter motor neuron—Sodium ions flood into the muscle cell, transferring the action potential. None of these.
Action potential reaches synapse—Calcium ions enter motor neuron—Acetylcholine is released by motor neuron—Acetylcholine binds to gated ion channels on sarcolemma—Sodium ions flood into the muscle cell, transferring the action potential.
Acetylcholine activates gated ion channels on the sarcolemma, causing and influx of calcium ions into the muscle cell. True False
False
Acetylcholine is released by the cells of the sarcolemma across the synapse. True False
False
The sarcomere is made entirely of actin filaments. True False
False
What happens to the neurotransmitter once an action potential is propagated on the muscle sarcolemma? It enters the muscle cell where it is used to produce ATP. It remains attached to the muscle cell until it eventually wears away. It is immediately broken down by an enzyme. It decomposes on its own within 30 seconds.
It is immediately broken down by an enzyme.
Calcium binds to the troponin-tropomyosin complex and allows myosin to access the actin filaments. True False
True
Calcium ions entering the motor neuron cell cause the release of acetylcholine. True False
True
Energy can be transferred in the muscle cell through the conversion of ATP into ADP. 10.4
True
The point of contact between a somatic motor neuron and a muscle cell is called a neuromuscular junction. True False
True
Muscle relaxation requires which enzyme in order to clear the action potential? acteylcholinesterase tropomyosin myosin all of these
acteylcholinesterase
Muscle fatigue is caused by all of the following except
aerobic respiration.
The sarcoplasmic reticulum contains acetylcholine calcium sodium all of these
calcium
Anaerobic respiration can provide enough ATP to sustain muscle activity for minutes to hours.
false
Pyruvic acid is converted to lactic acid in the presence of adequate oxygen.
false
Skeletal muscle can contract without nerve stimulation. True False
false
When the electrical impulse of the motor neuron reaches the synapse, the release of neurotransmitter is caused by the electrical activation of pumps in the synaptic cleft. the temporary electrical breakdown of the neuromuscular junction. the opening of electrically sensitive pores in the motor neuron. an increase in intra-cellular calcium when voltage-gated calcium channels open.
gated calcium channels open.
Glycogen reserves can release glucose for cellular respiration. Glycogen reserves are typically found in
skeletal muscle and the liver
A single action potential will create a single momentary contraction, not a continuous contraction. True False
true
Anaerobic respiration can provide enough ATP to sustain muscle activity for minutes to hours.
true
Creatine phosphate reserves are restored via phosphorylation by ATP during rest.
true
Recovery removes lactic acid and other toxins built up during muscle use.
true
The function of the neurotransmitter is to cause the opening of sodium channels in the muscle cell membrane. True False
true
The opening of sodium channels is essential for the initiation of an action potential in the muscle cell membrane. True False
true
