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True or False: Ca2+ binding to tropomyosin causes myosin to change shape, physically moving it away from its blocking position.
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What two molecules participate in cross-bridge interactions?
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Physiology Mod 8
Quiz questions that will be on the exam
| Question | Answer |
|---|---|
| True or False: Ca2+ binding to tropomyosin causes myosin to change shape, physically moving it away from its blocking position. | False |
| What two molecules participate in cross-bridge interactions? | Actin and Myosin |
| One motor neuron, plus all the muscle fibers it innervates, is known as a(n): | Motor Unit |
| True or False: Twitch summation results primarily from a sustained elevation in cytosolic Ca2+. | True |
| What phenomenon enables smooth muscle to maintain tension with comparatively less ATP consumption, as compared to skeletal muscle? | Latch phenomenon |
| True or False: A smooth muscle cell has many T tubules and well developed sarcoplasmic reticulum. | False |
| True or False: Muscles that produce precise, delicate movements have fewer muscle fibers in their motor units compared to muscles made for powerful movements. | True |
| What happens when two or more overlapping action potentials are “added” together within a muscle? | Twitch summation |
| Which molecule binds ATP in order for muscle contraction to occur? | Myosin |
| The end of the muscle attached to the more stationary part of the skeleton is called the ____________________. | Origin |
| Premotor and supplementary motor areas, with input from the ____________________, plan the voluntary motor command that is issued to the appropriate motor neurons by the primary motor cortex through a descending system. | Cerebrocerebellum |
| True or False: The crossed extensor reflex is a postural reflex that ensures that the opposite limb is in a position to bear the weight of the body as the injured limb is withdrawn from the stimulus. | True |
| True or False: Smooth muscle cells are interconnected by gap junctions found in intercalated discs that join cells together. | False |
| What types of muscles are involuntary in terms of movement? | cardiac and smooth |
| What is the first source for supplying additional ATP when exercise begins? | creatine phosphate |
| With eccentric contractions, the muscle ____________________. | Lengthens |
| True or False: Tropomyosin molecules are threadlike proteins that lie end to end alongside the groove of the actin spiral. | True |
| True or False: Slow and fast fibers are interconvertible. | False |
| A single ____________________ pulls the thin filament inward only a small percentage of the total shortening distance. | Power Stroke |
| Because of skeletal constraints, what is the maximum percentage that muscles can stretch or shorten relative to their length? | 30% |
| What shape are actin molecules? | Spherical |
| True or False: Unlike skeletal muscle cells, a single smooth muscle cell extends the full length of a muscle. | False |
| True or False: In contrast to muscle spindles, which lie in the tendons of muscle, Golgi tendon organs are in the belly of muscle. | False |
| A skeletal muscle fiber contains numerous ____________________, which are cylindrical intracellular structures. | Myofibrils |
| Lacking sarcomeres, smooth muscle does not have Z lines, but it does have ____________________ containing the same protein constituent found in Z lines. | Dense Bodies |
| Damage to the cerebellum or basal nuclei results in ____. | Clumsy movement |
| A(n) ____________________ is a rigid structure capable of moving around a pivot point known as a(n) fulcrum. | Lever |
| What molecules form the thick filaments within muscle? | Myosin |
| Muscle tension is produced internally within the ____. | Sarcomeres |
| The efferent neuron that innervates a muscle spindle's intrafusal fibers is known as a(n) ____________________ motor neuron. | Gamma |
| True or False: During the recovery period, fresh supplies of ATP are formed by oxidative phosphorylation using the newly acquired oxygen, which is provided by the sustained increase in breathing after exercise has stopped. | True |
| True or False: Viewed with an electron microscope, a myofibril displays alternating dark bands (the A bands) and light bands (the I bands). | True |
| What are the three main muscle types? | skeletal, cardiac, and smooth |
| What are the two membranous structures within the muscle fiber that play important roles in linking excitation to contraction? | transverse tubules and sarcoplasmic reticulum |
| What hormone, elevated during exercise, increases oxygen consumption? | epinephrine |
| ____________________ movements are the most complex type of motor activity. | Voluntary |
| The patellar tendon, or knee-jerk, reflex is a type of ____________________ reflex. | Stretch |
| True or False: Disuse atrophy occurs when a muscle is not used for a long period of time due to reduced or absent nerve supply. | False |
| The lateral sacs (alternatively known as terminal cisternae) store ____________________. | Calcium ions (Ca2+) |
| What are the two types of fast-twitch muscle fibers? | oxidative and glycolytic |
| True or False: Muscles are categorized as striated (skeletal and cardiac muscle) or unstriated (smooth muscle). | True |
| Oxidative fibers have high ____________________ content, which is why they are also called red fibers. | Myoglobin |
| In a(n) ____________________ contraction, the muscle is prevented from shortening, so tension develops at constant muscle length. | Isometric |
| Smooth muscle myosin can interact with actin only when the light chain is ____________________. | Phosphorylated |
| The local increase in inorganic phosphate from ____________________ breakdown is considered the primary cause of muscle fatigue. | ATP |
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hadland.j