A+P Exam 3

Types of muscle tissue
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Three Major Types of Skeletal Muscle FibersFast fibers Slow fibers Intermediate fibersFast fibersContract very quickly Have large diameter fatigue quicklySlow fibersslow to contract, slow to fatigueIntermediate fibersAre mid-sizedAnaerobic activitiesexample: weightlifting Use fast fibers Fatigue quickly with strenuous activityAerobic activitiesprolonged activity Supported by mitochondria Require oxygen and nutrientsUnlike skeletal muscle, cardiac muscle cellsAre small Have a single nucleus Have intercalated discsStructural Characteristics of Smooth Muscle TissueNonstriated tissue dense bodies Long, slender, and spindle shapedSkeletal muscle does each of these EXCEPT __________. store nutrients pump blood maintain posture produce movementpump bloodWhich of these statements about skeletal muscles is FALSE? They pull on tendons. They support soft tissues. Their fibers branch. They store nutrient reservesTheir fibers branch.Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for cushioning. contraction. secretion. conduction. peristalsis.contraction.At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium, come together to form a tenosynovium. sheath. satellite cell. ligament. tendon.tendonThe dense layer of connective tissue that surrounds an entire skeletal muscle is the endomysium. perimysium. fascicle. tendon. epimysium.epimysium.A fascicle is a collection of myofibrils in a muscle fiber. layer of connective tissue that separates muscle from skin. group of muscle fibers that are all part of the same motor unit. group of muscle fibers and motor neurons. group of muscle fibers that are encased in the perimysium.group of muscle fibers that are encased in the perimysium.Put the following structures in order from superficial to deep. 1. muscle fiber 2. perimysium 3. myofibril 4. fascicle 5. endomysium 6. epimysium6, 2, 4, 5, 1, 3Interactions between actin and myosin filaments of the sarcomere are responsible for muscle contraction. the striped appearance of skeletal muscle. muscle relaxation. muscle fatigue. the conduction of neural stimulation to the muscle fiber.muscle contraction.In a sarcomere, the central portion of thick filaments are linked laterally by proteins of the H band. I band. Z line. A band. M line.M lineSkeletal muscle fibers are formed from embryonic cells called sarcomeres. myoblasts. myomeres. fascicles. myofibrils.myoblastsThe plasma membrane of a skeletal muscle fiber is called the sarcoplasm. sarcolemma. sarcoplasmic reticulum. sarcosome. sarcomere.sarcolemma.The repeating unit of a skeletal muscle fiber is the myofibril. sarcoplasmic reticulum. myofilament. sarcolemma. sarcomere.sarcomere.Which of the following best describes the term sarcoplasmic reticulum? repeating unit of striated myofibrils thin filaments are anchored here storage and release site for calcium ions largely made of myosin molecules protein that accounts for elasticity of resting musclestorage and release site for calcium ionsThe skeletal muscle complex known as the triad consists of actin, myosin, and sarcomeres. filaments, myofibrils, and sarcomeres. a transverse tubule and two terminal cisternae. actin, myosin, and titin filaments. A bands, H bands, and I bands.a transverse tubule and two terminal cisternae.The region of the sarcomere containing the thick filaments is the M line. A band. H band. I band. Z line.A band.The area in the center of the A band that contains no thin filaments is the H band. I band. zone of overlap. Z line. M line.H bandCross-bridges are portions of actin molecules. troponin molecules. calcium ions. myosin molecules. tropomyosin molecules.myosin molecules.Each thin filament consists of a rod-shaped structure with "heads" projecting from each end. chains of myosin molecules. two actin protein strands coiled helically around each other. a double strand of myosin molecules. six molecules coiled into a helical structure.two actin protein strands coiled helically around each other.Which of the following best describes the term titin? storage and release site for calcium ions thin filaments are anchored here protein that accounts for elasticity of resting muscle largely made of myosin molecules repeating unit of striated myofibrilsprotein that accounts for elasticity of resting muscleThe region of the sarcomere that always contains thin filaments is the I band. H band. M line. Z line. A band.I bandAt rest, active sites on the actin are blocked by calcium ions. myosin molecules. troponin molecules. tropomyosin molecules. ATP molecules.tropomyosin molecules.All of the following proteins are part of the thin filaments except troponin. actin. tropomyosin. titin. None of the answers is correct; there are no exceptions.titinThin filaments are mostly made of the protein myosin. tropomyosin. nebulin. actin. titin.actinThick filaments are made of the protein tropomyosin. myosin. nebulin. titin. actin.myosinThe structural theory that explains how a muscle fiber contracts is called the ________ theory. sliding filament neuromuscular excitation-contraction coupling action-myosin interaction muscle contractionsliding filamentActive sites on the actin become available for binding after myosin binds to troponin. calcium binds to troponin. calcium binds to tropomyosin. actin binds to troponin. troponin binds to tropomyosin.calcium binds to troponin.Receptors for acetylcholine are located on the sarcomere. motor end plate. synaptic knob. transverse tubule. synaptic cleft.motor end plateThe action potential is conducted into a skeletal muscle fiber by neuromuscular junctions. sarcoplasmic reticulum. triads. motor end plates. transverse tubules.transverse tubulesThe most important factor in decreasing the intracellular concentration of calcium ion after contraction is diffusion of calcium out of the cell. active transport of calcium across the sarcolemma. diffusion of calcium into the sarcoplasmic reticulum. active transport of calcium into the sarcoplasmic reticulum. active transport of calcium into the synaptic cleft.active transport of calcium into the sarcoplasmic reticulum.Which of the following acts as an ATPase during the contraction cycle of muscle? troponin molecules tropomyosin molecules the tail portion of the myosin molecule the head portion of the myosin molecule actin moleculesthe head portion of the myosin moleculeWhen calcium ion binds to troponin, myosin shortens. tropomyosin rolls away from the active site. active sites on the myosin are exposed. muscle relaxation occurs. actin heads will bind to myosin.tropomyosin rolls away from the active siteIn rigor mortis ATP is depleted. sustained contractions occur. calcium ions keep binding to troponin. the myosin heads are attached to actin. All of the answers are correct.All of the answers are correctPhysical evidence that supports the sliding filament theory of muscle contraction includes the I band + H band distance is constant during contraction. constant distance between Z lines during contraction. decreased width of the H band during contraction. increased width of the I band during contraction. decreased width of the A band during contraction.decreased width of the H band during contraction.Triggering of the muscle action potential occurs after acetylcholinesterase is released from synaptic vesicles into the synaptic cleft. the action potential jumps across the neuromuscular junction. acetylcholine binds to chemically-gated channels in the motor end plate. calcium ion binds to channels on the motor end plate. Any of these can produce an action potential in the muscle cell.acetylcholine binds to chemically-gated channels in the motor end plate.When acetylcholine binds to receptors at the motor end plate, the sarcolemma becomesmore permeable to sodium ions.How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle? It would make the muscles less excitable. It would produce muscle weakness. It would cause muscles to stay contracted. It would cause muscles to stay relaxed. It would have little effect on skeletal muscles.It would cause muscles to stay contracted.Cross bridge detachment is caused by ________ binding to the myosin head. ATP acetylcholine acetylcholinesterase calcium magnesiumATPWhich of the following is important to increasing efficiency in tension production? lengthening the zone of overlap increasing the latent period increasing calcium reclamation a shortened relaxation phasea shortened relaxation phaseA muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in recruitment. complete tetanus. wave summation. incomplete tetanus. treppe.incomplete tetanusA single motor neuron together with all the muscle fibers it innervates is called a(n) dermatome. myotome. end foot. end plate. motor unit.motor unit.The type of contraction in which the muscle fibers do not shorten is called isometric. isotonic. concentric. tetany. treppe.isometric.In which of the following would the motor units have the fewest muscle fibers? thigh muscles calf muscles muscles of the neck postural muscles of the back muscles that control the eyesmuscles that control the eyeIn an isotonic contraction, muscle tension exceeds the load and the muscle lifts the load. tension rises and falls but the muscle length is constant. many twitches always fuse into one. postural muscles stabilize the vertebrae. the peak tension is less than the load.muscle tension exceeds the load and the muscle lifts the load.You try to pick up an object and discover that it is much heavier than you expected. Which process must occur in the muscle to increase tension so you can pick up the object? isotonic contraction wave summation recruitment treppe complete tetanusrecruitmentA single contraction-relaxation cycle in a muscle fiber produces a(n) twitch. action potential. tetanic contraction. cramp. motor unit.twitchA muscle produces its highest tension when in complete recovery. aerobic metabolism. tetanus. wave summation. treppe.tetanus.Fatigued muscles signify __________. lowered body temperature accumulation of pyruvic acid decreased pH oxygen recoverydecreased pHIn the liver, during the Cori cycle, lactic acid is shuffled to muscle cells. glucose is produced from lactic acid. glucose is released from glycogen. lactic acid is produced from glucose. lactic acid is produced from pyruvic acid.glucose is produced from lactic acid.During the recovery period the body's need for oxygen is increased because additional oxygen is required to restore energy reserves. creatine phosphate stimulates mitochondrial activity. the muscles produce much less ATP. muscle cells are producing ATP anaerobically. the liver requires more oxygen to produce lactic acid.additional oxygen is required to restore energy reserves.A resting muscle generates most of its ATP by glycogenolysis. aerobic metabolism of fatty acids. anaerobic respiration. hydrolysis of creatine phosphate. the tricarboxylic acid cycle.aerobic metabolism of fatty acids.Creatine phosphate is produced by the process of anaerobic respiration. can replace ATP in binding to myosin molecules during contraction. is only formed during strenuous exercise. cannot transfer its phosphate group to ADP. acts as an energy reserve in muscle tissue.acts as an energy reserve in muscle tissue.During anaerobic glycolysis, carbohydrate is metabolized. oxygen is not consumed. ATP is produced. pyruvic acid is produced. All of the answers are correct.All of the answers are correctAerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell. 50 25 100 70 9595After heavy exercise, if energy reserves in a muscle are depleted, ________ occurs. atrophy tetanus an oxygen debt paralysis treppean oxygen debtDuring the recovery period following exercise, all of the following are true except lactic acid is removed from muscle cells. heat is generated. oxygen is consumed at above the resting rate. muscle fibers are unable to contract. the muscle actively produces ATP.muscle fibers are unable to contract.At peak levels of muscle exertion the mitochondria can supply only about one-third of the energy required by the muscle. 80 percent of the energy required by the muscle. only about 10 percent of the energy required by the muscle. more than half of the energy required by the muscle. all of the energy required by the muscle.only about one-third of the energy required by the muscle.Which of the following would not lead to increased oxygen consumption? increased conversion of lactic acid to glucose increased anaerobic respiration by muscle cells increased heat production increased muscle activity All of the answers are correct; none would lead to increased oxygen consumption.increased anaerobic respiration by muscle cellsDecreased blood flow to a muscle could result in all of the following except muscle fatigue. an increase in intracellular lactic acid. a shift to anaerobic glycolysis. an oxygen debt. an increase in intracellular glycogen.an increase in intracellular glycogen.Heat energy gained from muscle contraction is released by the ________ system. endocrine integumentary respiratory urinary cardiovascularintegumentaryThe type of muscle fiber that is most resistant to fatigue is the ________ fiber. intermediate anaerobic fast slow high-densityslowMuscles that move the eyeball have ________ fibers. circular fast intermediate slow All of the answers are correct.fastDuring activities requiring aerobic endurance, oxygen debts are common. most of the muscle's energy is produced in mitochondria. fatigue occurs in a few minutes. glycogen and glycolysis are the primary sources of reserve energy. oxygen is not required.most of the muscle's energy is produced in mitochondria.When comparing slow muscle fibers to fast muscle fibers, slow fibers take about three times as long to reach peak tension. generate much less tension. are rich in the red protein myoglobin. have much smaller fiber diameters. All of the answers are correct.All of the answers are correctWhich of the following types of muscle fibers are best adapted for prolonged contraction such as standing all day? uninucleated fibers fast fibers striated fibers slow fibers intermediate fibersslow fibersWhich of the following statements is false? Cardiocytes are interconnected through intercalated discs. Skeletal muscle and cardiac muscle stimulation is neural. Cardiac muscle has a striated appearance. Skeletal muscle contractions may be summated. Cardiac muscle contractions cannot be summated.Skeletal muscle and cardiac muscle stimulation is neural.The ability of smooth muscle to function over a wide range of lengths is called extensibility. plasticity. contractility. variability. elasticity.plasticity.Which of the following is not a function of smooth muscle tissue? altering the diameter of the respiratory passageways forcing blood from the heart into the major arteries elevating hairs on the arm forcing urine out of the urinary tract moving food materials along the digestive tractforcing blood from the heart into the major arteriesSmooth muscle contracts when calcium binds to __________ and activates __________. calmodulin; troponin troponin; tropomyosin calmodulin; myosin light chain kinase troponin; myosin light chain kinasecalmodulin; myosin light chain kinaseWhich of the following is not a function of the nervous system? integrate sensory information sense the internal and external environments control peripheral effectors coordinate voluntary and involuntary activities direct long-term functions, such as growthdirect long-term functions, such as growthThe ________ nervous system is composed of the brain and spinal cord.centralThe ________ nervous system controls the skeletal muscles.somaticThe ________ division of the peripheral nervous system brings sensory information to the central nervous system. peripheral autonomic somatic parasympathetic afferentafferentThe ________ division of the nervous system carries motor commands to muscles and glands. autonomic afferent spinal peripheral efferentefferent________ nerves are nerves that connect to the brain.cranial________ nerves are nerves that connect to the spinal cord.spinalJosh and a bunch of friends decided to see how many people they could squeeze into a small car for a charity event. Once inside, Josh felt it get hot, smelly, and like the air was getting squished out of his lungs. He also noticed aches and pains in his joints. Which of the following statements best describes the type of sensory neurons involved? His interoceptors were monitoring his respiratory system. His exteroceptors were bringing in information from the outside world. The proprioceptors were monitoring the position of his skeletal muscles and joints. The interoceptors, exteroceptors, and proprioceptors were all monitoring his condition.The interoceptors, exteroceptors, and proprioceptors were all monitoring his condition.Which of these components is usually absent from a neuron? cell body dendrites centrioles axonscentriolesThe most abundant class of neuron in the central nervous system ismultipolarThe cytoplasm that surrounds the nucleus of a neuron is called the nucleoplasm. perikaryon. neuroplasm. sarcoplasm. protoplasm.perikaryon.Branches that may occur along an axon are called synapses. telodendria. collaterals. synaptic terminals. hillocks.collateralsAxons terminate in a series of fine extensions known as terminals. dendrites. telodendria. synapses. collaterals.telodendriaNeurotransmitters ready for release are stored in synapticvesiclesWhich of the following activities or sensations is/are not monitored by interoceptors? urinary activities taste activities of the digestive system cardiovascular activities sightsight________ carry sensory information to the CNS. Motor neurons Multipolar neurons Interneurons Afferent neurons Efferent neuronsAfferent neurons________ provide information about the external environment. Proprioceptors Spinal nerves Internoceptors Anaxonic neurons ExteroceptorsExteroceptorsThe plasma membrane of an axon is called theaxolemmaThe basic functional unit of the nervous system is theneuronThe most common neuron of the nervous system is the unipolar neuron. microglial cell. bipolar neuron. interneuron. externoceptor.interneuronNeuron cell bodies in the PNS are clustered together in masses called nuclei. nerves. ganglia. tracts. fibers.gangliaWhich of the following is an example of a myelin producing cell in the central nervous system (CNS)? ependymal cells astrocytes schwann cells oligodendrocytesoligodendrocytesNeuroglia perform all of these functions EXCEPT __________. secrete CSF release neurotransmitters provide supportive framework regulate extracellular fluid compositionrelease neurotransmittersWhich of the following is not a function of the neuroglia? maintenance of blood-brain barrier support phagocytosis memory secretion of cerebrospinal fluidmemoryThe largest and most numerous of the glial cells in the central nervous system are the oligodendrocytes. microglia. ependymal cells. satellite cells. astrocytes.astrocytes.Functions of astrocytes include all of the following except maintaining the blood-brain barrier. responding to neural tissue damage. conducting action potentials. forming a three-dimensional framework for the CNS. guiding neuron development.conducting action potentials.________ account for roughly half of the volume of the nervous system.NeurogliaThe function of the astrocytes in the CNS includes which of the following? repairing damaged neural tissue guiding neuron development maintaining the blood-brain barrier adjusting the composition of the interstitial fluid All of the answers are correct.All of the answers are correctThe neuroglial cells that participate in maintaining the blood-brain barrier are the oligodendrocytes. astrocytes. microglia. Schwann cells. ependymal cells.astrocytesThe myelin sheath that covers many CNS axons is formed by satellite cells. microglia. ependymal cells. oligodendrocytes. astrocytes.oligodendrocytes.________ line the brain ventricles and spinal canal. Ependymal cells Microglia Oligodendrocytes Satellite cells AstrocytesEpendymal cellsGlial cells that surround the neurons in ganglia are oligodendrocytes. ependymal cells. satellite cells. microglia. astrocytes.satellite cellsExtensive damage to oligodendrocytes in the CNS could result in loss of the structural framework of the brain. a breakdown of the blood-brain barrier. loss of sensation and motor control. inability to produce scar tissue at the site of an injury. decreased production of cerebrospinal fluid.loss of sensation and motor controlThe tiny gaps between adjacent Schwann cells are called terminals. nodes of Ranvier. neurillema. vesicles. axolemma.nodes of Ranvier.Which of the following is not true regarding the establishment of a neuron's resting potential? Chemical and electrical forces both favor sodium ions entering the cell. Electrical forces push sodium ions into the cell. Resting membrane permeability to Na+ is very low. Ion pumps in the plasma membrane eject sodium ions as fast as they cross the membrane. The chemical gradient for potassium ions tends to drive them out of the cell.Electrical forces push sodium ions into the cell.Ion channels that are always open are called ________ channels. regulated leak active gated localleakOpening of sodium channels in the axon membrane causes inhibition. repolarization. hyperpolarization. increased negative charge inside the membrane. depolarization.depolarizationVoltage-gated channels are present along the perikaryon of neurons. in the membrane that covers axons. on the surface of dendrites. at the motor end plate. on the soma of neurons.in the membrane that covers axons.The sodium-potassium ion exchange pump transports sodium ions into the cell during depolarization. moves sodium and potassium opposite to the direction of their electrochemical gradients. depends on a hydrogen gradient for energy. transports potassium ions out of the cell during repolarization. must reestablish ion concentrations after each action potential.moves sodium and potassium opposite to the direction of their electrochemical gradients.________ open or close in response to binding specific molecules. Chemically gated channels Leak channels Activated channels Voltage-gated channels Voltage-gated and chemically gated channelsChemically gated channelsIf the sodium-potassium pumps in the plasma membrane fail to function, all of the following occur except the membrane will slowly lose its capacity to generate action potentials. the neuron will slowly depolarize. the intracellular concentration of sodium ions will increase. the intracellular concentration of potassium ions will increase. the inside of the membrane will have a resting potential that is more positive than normal.the intracellular concentration of potassium ions will increase.Graded potentials produce an effect that spreads actively across the membrane surface. may be either a depolarization or a hyperpolarization. produce an effect that increases with distance from the point of stimulation. are often all-or-none. cause repolarization.may be either a depolarization or a hyperpolarizationWhen potassium channels open and the ions diffuse through the membrane, the inside of the membrane will become more negative. the membrane will depolarize to threshold. the membrane will become depolarized. the inside of the membrane will become more positive. there will be almost no effect on transmembrane potential.the inside of the membrane will become more negative.Voltage-gated sodium channels have both an activation gate and a(n) ________ gate. swinging ion inactivation threshold repolarizationinactivationIf acetylcholine (ACh) causes inhibition of a postsynaptic neuron, to what type of membrane channel did the ACh bind? chemically-regulated sodium channel mechanically-regulated channel chemically-regulated potassium channel voltage-regulated sodium channel voltage-regulated calcium channelchemically-regulated potassium channelIf the axolemma becomes more permeable to potassium ion, the membrane will depolarize to threshold. a stronger stimulus will be required to cause an action potential. sodium ions will enter the cell to replace the lost potassium ions. the inside of the membrane will have a positive charge. the membrane will depolarize to +30 mV.a stronger stimulus will be required to cause an action potential.A movement of charges in response to a potential difference is called current. electricity. action potential. hyperpolarization. depolarization.currentThe sum of the electrical and chemical forces acting on an ion is known as its thermodynamic difference. summation difference. action potential. electrochemical gradient. permeability gradienelectrochemical gradient.Where do most action potentials originate? Axon terminal Nodes of Ranvier Initial segment Cell bodyinitial segmentThe same ________ can have different effects depending on the properties of the ________. hormone; neurotransmitter receptor; neurotransmitter propagation; neurotransmitter neurotransmitter; receptor substrate; receptorneurotransmitter; receptorDuring repolarization of a neuron sodium ions move into the cell. sodium ions move out of the cell. potassium ions move out of the cell. both sodium and potassium ions move into the cell. potassium ions move into the cell.potassium ions move out of the cell.How would the absolute refractory period be affected if voltage-regulated sodium channels failed to inactivate? It would be basically unaffected. It would be much briefer. It would last indefinitely.It would last indefinitelyA threshold stimulus is the peak of an action potential. electrical current that crosses the synaptic cleft. depolarization necessary to cause an action potential. hyperpolarization of an axon. resting potential.depolarization necessary to cause an action potential.Which of the following is true about threshold for an action potential? The membrane begins to hyperpolarize. Threshold for a typical neuron is approximately -30 mV. Voltage-gated potassium channels begin to open. It is more positive than the resting potential. Voltage-gated potassium channels begin to closeIt is more positive than the resting potential.The ion that triggers the release of acetylcholine into the synaptic cleft is sodium. chloride. potassium. calcium. magnesium.calciumIf the axon terminal of a motor neuron suddenly became permeable to calcium ion, neurotransmitter release will be blocked. the neuron will become unable to stimulate the muscle cell. the neuron will fire an action potential. the motor end plate will be hyperpolarized. the motor end plate will be depolarized.the motor end plate will be depolarized.The simplest level of information processing takes place at the __________. axon terminals dendrites soma axon hillockaxon hillock