Ivy Tech APHY 101 – Muscle System Practice Test

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• What are the main sources of Ca2+ for smooth muscle contraction?
• What term describes a measure of potential energy generated by separated charge, measured in volts or millivolts?
• Which set of terms describes the phases of a muscle twitch?
• What is the role of the terminal cisterna of the sarcoplasmic reticulum in excitation-contraction coupling?
• Which is an example of multi-unit smooth muscle?
• During the sliding filament contraction, which region of the sarcomere shortens?
• Which subunits compose troponin and their roles?
• During elbow flexion, how does the brachialis contribute relative to the biceps brachii?
• During elbow flexion, which muscle serves as a synergist?
• The structure that includes axon terminals, the synaptic cleft, and the sarcolemma with acetylcholine receptor channels is the
• What forms the cross‑bridge by binding to actin during contraction?
• At the neuromuscular junction, acetylcholine release leads to sodium influx and depolarization, creating an end-plate potential. This sequence is described as which event?
• Which connective tissue layer surrounds an entire muscle and may blend with fascia?
• Intercalated discs contain which components?
• Which smooth muscle type is associated with sustained contraction such as in sphincters and vascular walls?
• Satellite cells differentiate into what type of cells to repair muscle tissue?
• Which term describes the ability of a muscle to shorten forcibly when stimulated?
• What occurs during the power stroke in the cross-bridge cycle?
• The smallest contractile unit of muscle; extends from one Z disc to another
• Which fibers possess a combination of fast and slow-twitch characteristics and can convert to behave more like fast or slow-twitch fibers based on usual activities performed?
• Which property is associated with a muscle fiber having a fully developed sarcolemma and sarcoplasmic reticulum?
• During the cross‑bridge cycle, what describes the power stroke?
• When the end-plate potential reaches threshold, which event occurs first?
• Which phenomenon is described by a gradual increase in contraction strength with rapid stimuli, reflecting the muscle's warming up and enzyme efficiency improvements?
• Which ion binds to troponin to expose myosin‑binding sites on actin, enabling contraction?
• Which molecule provides the energy for cells, including muscle contraction, produced via both anaerobic and aerobic pathways?
• Thin filaments are composed of which combination of proteins?
• What is the muscle response to a single, brief threshold stimulus called?
• What is a fascicle?
• Which is required for cross‑bridge detachment during muscle contraction?
• The origin of a muscle is defined as the attachment site that typically remains what during movement?
• Which statement about regulation of smooth muscle contraction is correct?
• Which statement accurately describes isotonic and isometric contractions, with examples?
• Which phase occurs first after a stimulus and shows no measurable tension due to EC coupling processes?
• What are the four fundamental properties of muscle tissue?
• Which contraction occurs when the muscle generates tension but does not shorten because the external load is greater than the force produced?
• What stores calcium in muscle cells?
• What causes cross-bridge detachment?
• During the repolarizing phase of an action potential, which ion movement predominates?
• Which statement best describes mitochondrial density and metabolism in slow-twitch vs fast-twitch muscle fibers?
• Inability to contract a muscle when stimulated is called.
• Which region does not contain overlapping thick and thin filaments, located in the center of the thick filament region?
• Which muscle is the prime mover for elbow flexion?
• After Na+ channels close, which phase describes the membrane becoming more negative as K+ leaves the cell?
• Which substrate pattern best describes fuel use in resting vs trained skeletal muscle during aerobic respiration?
• A protein of muscle that together with tropomyosin forms a regulatory protein complex and permits muscular contraction when combined with calcium ions?
• During contraction, thin filaments slide past thick filaments causing actin and myosin to overlap more; cross bridges form and break several times, ratcheting thin filaments toward the center of the sarcomere. Which model describes this process?
• Which muscle tissue is striated and typically under voluntary control?
• What is the connective tissue sheath that surrounds the entire muscle called?
• What is the delicate connective tissue surrounding each muscle fiber called?
• Which muscle tissue forms the walls of the heart and contains intercalated discs?
• Which contraction type occurs when there is tension without shortening because the load cannot be moved?
• What is rigor mortis?
• During rapid stimulation, when a second contraction occurs before the first has completed relaxation, this is called?
• What percentage of ATP used by muscle activity comes from aerobic respiration?
• At low intracellular Ca2+ concentration, what happens to the actin binding sites?
• What term describes the gradual increase in contraction strength following rapid, repeated stimulation due to enzymatic warming?
• Describe the sequence from motor neuron action potential to calcium release from the sarcoplasmic reticulum in skeletal muscle.
• Why is a tetanus contraction not possible in cardiac muscle?
• The electrical potential of the cell membrane becomes less negative or more positive due to Na+ or Ca2+ entering the cell. This is called what?
• What does the size principle of motor unit recruitment state?
• What is the significance of intercalated discs in cardiac muscle?
• Which region of the sarcomere contains the entire length of thick filaments?
• During prolonged endurance activities, which energy system provides most energy for ATP production?
• Which components bind acetylcholine on the muscle cell surface?
• Which energy system uses oxygen to produce 30+ ATP and occurs in the mitochondria?
• Which regulatory proteins control cross-bridge formation and how does calcium affect them?
• Which energy system dominates during a 20-second sprint?
• What term describes the age-related loss of muscle mass and strength?
• Arrange the connective tissue layers from outermost to innermost.
• Which statement is true about intercalated discs in cardiac muscle?
• What event must be reached to open voltage-gated Na+ channels during an action potential?
• The thick filaments run the entire length of an A band and are composed of which protein?
• During cocking of the myosin head, what occurs?
• What is the role of Ca2+ in contraction at sufficient intracellular concentration?
• What is the period of a muscle twitch during which the muscle relaxes as Ca2+ re-enters the sarcoplasmic reticulum?
• What is the red pigment in the sarcoplasm that stores oxygen?
• What prevents actin-myosin interaction in resting muscle?
• Which contraction involves a change in muscle length while maintaining constant tension?
• The dark band that extends the length of the thick filaments and contains myosin is called which band?
• Which is a primary function of muscle tissue?
• What term describes the electrical signal that rapidly depolarizes and repolarizes the muscle cell membrane and propagates along the sarcolemma and into T-tubules?
• During muscle contraction, which event triggers the release of calcium from the sarcoplasmic reticulum?
• At rest, the cell typically has a membrane potential of about what value due to ion distribution and the Na+/K+ pump?
• What term describes a muscle's ability to receive and respond to stimuli?
• What is a muscle fiber?
• Muscle atrophy is best described as?
• Which connective tissue layer surrounds fascicles (groups of muscle fibers)?
• In excitation-contraction coupling, what is the role of T-tubules and the sarcoplasmic reticulum?
• Which processes are involved in post-exercise recovery of muscle?
• Which term describes muscle contractions where the load causes the muscle to shorten while maintaining constant tension?
• Which region contains only thin filaments?
• Which muscle fiber type is more reliant on glycolysis and has lower mitochondrial density?
• Ca2+ release from terminal cisternae is triggered by which receptor?
• How does increasing the load affect the velocity of a muscle contraction?
• What is the cytoplasm of a muscle fiber?
• How is cytosolic Ca2+ removed after contraction in skeletal muscle?
• Which nerve innervates the deltoid muscle?
• At the onset of contraction, ATP is produced slowly by aerobic metabolism; what explains the subsequent rise in aerobic ATP production after about 60 seconds?
• Which region is the lighter area in the midsection of the dark A band where filaments do not overlap?
• What term describes a bundle of muscle fibers surrounded by perimysium?
• Which sequence describes the events in generation of an action potential in a skeletal muscle fiber?
• A smooth, sustained contraction resulting from high-frequency stimulation is known as:
• Which structure marks the boundary between adjacent sarcomeres?
• The plateau phase of the cardiac action potential is due to which process?
• What role does phosphocreatine play in muscle contraction?
• Excess post-exercise oxygen consumption, or EPOC, is the extra oxygen the body must take in after exercise to complete restorative processes such as reformation of creatine phosphate and clearing lactic acid back to glucose.
• Which muscle tissue is found in hollow organs and lacks striations?
• Which chemical transmitter stimulates skeletal muscle by binding to receptors on the muscle cell?
• Ions move across a membrane down an electrical gradient toward an opposite charge and/or down a chemical gradient to an area of lower solute concentration. This movement is described as the
• The difference in electric potential between the interior and exterior of a biological cell is termed the
• Which protein is the principal contractile component found in thick filaments?
• At the molecular level, how is smooth muscle contraction regulated?
• The wasting away of a body organ or tissue is called?
• What rod-like structures run parallel to the length of a muscle fiber and contain sarcomeres end-to-end?
• Which energy system dominates during shortest, high-intensity activity lasting a few seconds?
• Which protein is the principal contractile component found in thin filaments?
• Cardiac muscle shares sarcomere structure with skeletal muscle but has specialized junctions for conduction. What are these junctions called?
• Pacemaker cells are located in which heart structures?
• What is the plasma membrane of a muscle fiber?
• What ion movement triggers the end-plate potential at the neuromuscular junction?
• What is described as cross-bridge formation in the cycle?
• In a sarcomere, which region contains only thick filaments?
• In the cardiac action potential, Phase 0 corresponds to which event?
• What consists of one motor neuron and all the muscle fibers it innervates called?
• What directly triggers contraction after an action potential in skeletal muscle?
• What is the purpose of the plateau phase in the cardiac action potential?
• Which pumps are responsible for re-sequestering Ca2+ into the SR during skeletal muscle relaxation?
• Distinguish single-unit and multi-unit smooth muscle with examples.
• Which structure conducts the action potential from the surface into the interior of the muscle fiber?
• What initiates Ca2+ release from the sarcoplasmic reticulum in skeletal muscle?
• Which type of muscle fibers are fatigue-resistant, O2 rich, best for endurance activities, lactate intolerant, aerobic, and fuel from blood nutrients?
• At higher intracellular Ca2+ concentrations, which sequence leads to contraction?
• Which regulatory movement occurs when calcium is present, causing tropomyosin to uncover myosin-binding sites on actin?
• The thick filaments are connected in the middle of the sarcomere by which structure?
• Which statement best differentiates phasic and tonic smooth muscle contractions?
• Regular resistance exercise increases muscle force by causing muscle cells to increase in size, a process known as hypertrophy.
• What is the term for resetting the myosin head to the high‑energy state powered by ATP hydrolysis?
• Which is the basic contractile unit of skeletal muscle?
• Which unique high-energy molecule is stored in muscles and serves as the initial energy source to regenerate ATP from ADP and P, fueling about 10 seconds of intense contraction?
• Which sequence describes the cross-bridge cycle during skeletal muscle contraction?
• Which protein is listed as a component of thin filaments along with actin, troponin, and tropomyosin?
• At the neuromuscular junction, what event leads to the generation of an end plate potential?
• What is the functional consequence of the cardiac muscle's long refractory period?
• Which energy pathway involves producing cellular energy without oxygen, using glycolysis to yield 2 ATP per glucose and produce lactic acid?
• Which structure anchors the thin filaments to the midline and connects myofibrils to one another?
• The flow of electrical charge (ions) between two points, which can be used to do work, is called
• Which muscle tissue is primarily responsible for generating heat, especially during skeletal activity?
• In skeletal muscle, which regulatory step exposes myosin-binding sites on actin?
• Which term describes the ability of a muscle to be stretched?
• Which describes a greater degree of wave summation with a sustained, but quivering, contraction?
• Which tissue forms the walls of the heart?
• Which line bisects the H zone vertically?
• Block of acetylcholinesterase would cause?
• The thick filaments in skeletal muscle are primarily composed of which protein?
• Which muscle acts as the antagonist during elbow flexion?
• Which statement best describes the source of calcium for skeletal muscle contraction during EC coupling?
• What is oxygen debt (EPOC) and how is it repaid after exercise?
• What are the two major histological features that support contraction in skeletal muscle fibers?
• Which statement about Type IIb fibers is NOT true?
• During an action potential, the membrane potential returning toward the resting value as potassium exits the cell is called
• A protein that forms the regulatory complex with troponin regulating the interaction of actin and myosin by blocking cross-bridge formation unless troponin is combined with calcium ions?
• Which fibers are fatigable, contract rapidly, are anaerobic and ideal for short-term powerful movements, and depend on glycogen reserves for fuel?
• Which statement is NOT typically listed as a principal mechanism of skeletal muscle fatigue?
• How does aging affect muscle mass and function?
• Which is an example of a single-unit smooth muscle?
• Which region is the light area consisting of thin filaments only?
• Which protein binds calcium and, together with tropomyosin, regulates the interaction of actin and myosin?
• What cells are primarily responsible for muscle repair and growth after injury?
• What structures connect cardiac muscle cells to form a functional syncytium?
• Which energy system provides quick energy for about 10 seconds?
• Which term describes the ability of a muscle to recoil to its resting length after being stretched?
• The Z disc is at the center of which band?
• Which structure contains repeating sarcomeres?
• What is the contraction type where tension rises to a maximum and contractions fuse into a smooth, sustained plateau?
• Which is not a component of the neuromuscular junction?
• Which muscle tissue type is attached to the skeleton, striated, and voluntary?
• What initiates the end-plate potential at the neuromuscular junction?
• What does the optimum resting length of a muscle allow in terms of force development?
• What concept describes how the resting length of a muscle relates to the tension it can produce?
• Which pump maintains the resting membrane potential by moving Na+ out of the cell and K+ into the cell?
• Which statement best differentiates Type I and Type II muscle fibers in terms of fatigue resistance, mitochondria, and color?
• Which sequence correctly lists the four steps of the cross-bridge cycle in order?
• Which structure is the sheet of proteins on the midline of the light I band that anchors thin filaments and connects myofibrils to one another?
• Which structure is formed by enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules?
• The dense, regular connective tissue that attaches muscle to bone is known as?
• Which of the following is a characteristic of smooth muscle that distinguishes it from skeletal muscle?
• What are the immediate products of ATP breakdown in muscle contraction?
• Which muscle tissue lacks striations and is found in hollow organs?
• Which sequence correctly describes skeletal muscle excitation-contraction coupling?
• Which phase of a muscle twitch follows the latent period and involves active cross‑bridges and peak tension?
• What is the length-tension relationship in skeletal muscle?
• What are tubular infoldings of the sarcolemma that penetrate through the cell and emerge on the other side and contain voltage-gated channels to rapidly conduct action potentials into the cell interior?
• Formed in muscle fibers by myofilaments of actin and myosin arranged in an organized manner; composed of hundreds of sarcomeres end-to-end
• What is the end plate potential and how does it relate to a muscle action potential?
• What is the sliding filament mechanism?
• Which region is the light area with thin filaments only?
• What condition permits continuation of cross-bridge cycles?
• Which muscle fiber type is most associated with endurance performance due to its high oxidative capacity?
• Which substance, stored in the sarcoplasmic reticulum, acts as the trigger for muscle contraction when released?
• Which nerve innervates the quadriceps femoris muscle group?
• Which mechanism releases Ca2+ from the sarcoplasmic reticulum?
• What is the 'latch state' in smooth muscle and its functional significance?
• In smooth muscle, what structures provide attachment points for contraction similar to Z-discs in skeletal muscle?
• Which statement best describes slow-twitch fibers?
• Which cardiac feature connects cardiac muscle cells?
• Which neurotransmitter is released at the neuromuscular junction and what receptor mediates its effect?