front 1 Muscle contraction will always promote movement of body parts regardless of how they are attached.
| back 1 B |
front 2 Muscle tissue has all of the following properties except ________.
| back 2 D |
front 3 Which type of muscle CANNOT contract without being stimulated by the nervous system?
| back 3 A |
front 4 Which muscle characteristic describes the ability of muscle to respond to a stimulus?
| back 4 excitability |
front 5 Which of the following is CORRECTLY paired?
| back 5 skeletal muscle: voluntary control |
front 6 Muscle tissue does NOT ________.
| back 6 produce blood cells |
front 7 A contraction in which the muscle does not shorten but its tension increases is called isometric contraction.
| back 7 True |
front 8 Muscle cells store more creatine phosphate than ATP resulting in the muscle having a reserve source of energy.
| back 8 T |
front 9 Cells of unitary smooth muscle are found in the longitudinal and circular muscle layers of the intestine.
| back 9 T |
front 10 Cardiac muscle has a limited regenerative capacity.
| back 10 T |
front 11 What is the role of tropomyosin in skeletal muscles?
| back 11 B |
front 12 What does excess postexercise oxygen consumption represent?
| back 12 D |
front 13 Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptors.
| back 13 latent |
front 14 What is the primary function of wave summation?
| back 14 produce smooth, continuous muscle contraction |
front 15 Rigor mortis occurs because ________.
| back 15 A |
front 16 Which of the choices below does not describe how excess postexercise oxygen consumption (oxygen deficit) restores metabolic conditions?
| back 16 C |
front 17 Which of the following is not a component of the standard treatment for muscle strain?
| back 17 stretching of the muscle |
front 18 Which of the following is not a connective tissue sheath that wraps individual muscle fibers?
| back 18 aponeurosis |
front 19 Which of the following is not a role of ionic calcium in muscle contraction?
| back 19 activates epinephrine released from adrenal gland |
front 20 The sliding filament model of contraction involves ________.
| back 20 B |
front 21 What is the most distinguishing characteristic of muscle tissue?
| back 21 the ability to transform chemical energy into mechanical energy |
front 22 Three discrete types of muscle fibers are identified on the basis of their size, speed, and endurance. Which of the following athletic endeavors best represents the use of red fibers?
| back 22 a long, relaxing swim |
front 23 In the muscles of the limbs, the origin usually lies proximal to the insertion.
| back 23 T |
front 24 What is the relationship between the number of motor neurons recruited and the number of skeletal muscle fibers innervated?
| back 24 B |
front 25 Which of the following is most directly responsible for the coupling of excitation to contraction of skeletal muscle fibers?
| back 25 Calcium ions. |
front 26 What is name given to the regularly spaced infoldings of the sarcolemma?
| back 26 transverse or T tubules |
front 27 A triad is composed of a T-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum. How are these components connected?
| back 27 A series of proteins that control calcium release. |
front 28 Excitation of the sarcolemma is coupled or linked to the contraction of a skeletal muscle fiber. What specific event initiates the contraction?
| back 28 Calcium release from the sarcoplasmic reticulum initiates the contraction. |
front 29 Excitation-contraction coupling is a series of events that occur after the events of the neuromuscular junction have transpired. The term excitation refers to which step in the process?
| back 29 Excitation, in this case, refers to the propagation of action potentials along the sarcolemma. |
front 30 In a neuromuscular junction, synaptic vesicles in the motor neuron contain which neurotransmitter?
| back 30 acetylcholine (ACh) |
front 31 When an action potential arrives at the axon terminal of a motor neuron, which ion channels open?
| back 31 voltage-gated calcium channels |
front 32 What means of membrane transport is used to release the neurotransmitter into the synaptic cleft?
| back 32 exocytosis |
front 33 The binding of the neurotransmitter to receptors on the motor end plate causes which of the following to occur?
| back 33 Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate. |
front 34 How is acetylcholine (ACh) removed from the synaptic cleft?
| back 34 acetylcholinesterase (AChE; an enzyme) |
front 35 The action potential on the muscle cell leads to contraction due to the release of calcium ions. Where are calcium ions stored in the muscle cell?
| back 35 terminal cisternae of the sarcoplasmic reticulum |
front 36 What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell?
| back 36 arrival of an action potential |
front 37 The binding of calcium to which molecule causes the myosin binding sites to be exposed?
| back 37 troponin |
front 38 A myosin head binds to which molecule to form a cross bridge?
| back 38 actin |
front 39 What causes the myosin head to disconnect from actin?
| back 39 binding of ATP |
front 40 What energizes the power stroke?
| back 40 hydrolysis of ATP |
front 41 The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. What is a cross bridge?
| back 41 A myosin head bound to actin |
front 42 What structure is the functional unit of contraction in a skeletal muscle fiber?
| back 42 The sarcomere |
front 43 Calcium ions couple excitation of a skeletal muscle fiber to contraction of the fiber. Where are calcium ions stored within the fiber?
| back 43 Calcium ions are stored in the sarcoplasmic reticulum. |
front 44 After a power stroke, the myosin head must detach from actin before another power stroke can occur. What causes cross bridge detachment?
| back 44 ATP binds to the myosin head. |
front 45 How does the myosin head obtain the energy required for activation?
| back 45 The energy comes from the hydrolysis of ATP. |
front 46 What specific event triggers the uncovering of the myosin binding site on actin?
| back 46 Calcium ions bind to troponin and change its shape. |
front 47 When does cross bridge cycling end?
| back 47 Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin. |
front 48 Action potential propagation in a skeletal muscle fiber ceases when acetylcholine is removed from the synaptic cleft. Which of the following mechanisms ensures a rapid and efficient removal of acetylcholine?
| back 48 Acetylcholine is degraded by acetylcholinesterase. |
front 49 The neuromuscular junction is a well-studied example of a chemical synapse. Which of the following statements describes a critical event that occurs at the neuromuscular junction?
| back 49 Acetylcholine is released by axon terminals of the motor neuron. |
front 50 Action potentials travel the length of the axons of motor neurons to the axon terminals. These motor neurons __________.
| back 50 extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber |
front 51 Calcium entry into the axon terminal triggers which of the following events?
| back 51 Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine. |
front 52 Acetylcholine binds to its receptor in the sarcolemma and triggers __________.
| back 52 the opening of ligand-gated cation channels |
front 53 Sodium and potassium ions do not diffuse in equal numbers through ligand-gated cation channels. Why?
| back 53 D |
front 54 Myasthenia gravis is sometimes treated medically by a treatment that involves ________.
| back 54 inhibiting the action of acetylcholinesterase |
front 55 Cross bridge formation between myosin heads and actin molecules is caused by the elevation of calcium ion concentration in the cytosol. During rigor mortis, this elevation of calcium ion concentration in the cytosol is permanent because ________.
| back 55 mitochondria stop producing ATP molecules required by the sarcoplasmic reticulum's calcium ion pumps |
front 56 In a bedridden patient recovering from a badly fractured femur, disuse atrophy in the thigh muscles is caused by _________.
| back 56 decreased synthesis of muscle proteins and/or increased breakdown of muscle proteins |
front 57 Once a motor neuron has fired, all the muscle fibers in a muscle contract.
| back 57 F |
front 58 The thin filaments (actin) contain a polypeptide subunit G actin that bears active sites for myosin attachment.
| back 58 T |
front 59 The force of muscle contraction is controlled by multiple motor unit summation or recruitment.
| back 59 T |
front 60 Eccentric contractions are more forceful than concentric contractions.
| back 60 T |
front 61 A motor neuron and all the muscle cells that it stimulates are referred to as a motor end plate.
| back 61 F |
front 62 Peristalsis is characteristic of smooth muscle.
| back 62 T |
front 63 During isometric contraction, the energy used appears as movement.
| back 63 F |
front 64 One of the important functions of skeletal muscle contraction is production of heat.
| back 64 T |
front 65 An increase in the calcium ion level in the sarcoplasm starts the sliding of the thin filaments. When the level of calcium ions declines, sliding stops.
| back 65 T |
front 66 Muscle tone is the small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units.
| back 66 T |
front 67 A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell.
| back 67 T |
front 68 The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily.
| back 68 T |
front 69 When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length.
| back 69 T |
front 70 Most skeletal muscles contain ________.
| back 70 a mixture of fiber types |
front 71 Fatigued muscle cells that recover rapidly are the products of ________.
| back 71 intense exercise of short duration |
front 72 The strongest muscle contractions are normally achieved by ________.
| back 72 increasing the stimulation up to the maximal stimulus |
front 73 Which of the following would be recruited later in muscle stimulation when contractile strength increases?
| back 73 motor units with larger, less excitable neurons |
front 74 Excitation-contraction coupling directly requires which of the following substances?
| back 74 Ca2+ and ATP |
front 75 Which of the following is a factor that affects the velocity and duration of muscle
| back 75 load on the fiber |
front 76 Myoglobin ________.
| back 76 stores oxygen in muscle cells |
front 77 What structure in skeletal muscle cells functions in calcium storage?
| back 77 sarcoplasmic reticulum |
front 78 Creatine phosphate functions in the muscle cell by ________.
| back 78 storing energy that will be transferred to ADP to resynthesize ATP |
front 79 The major function of the sarcoplasmic reticulum in muscle contraction is to ________.
| back 79 regulate intracellular calcium concentration |
front 80 What produces the striations of a skeletal muscle cell?
| back 80 the arrangement of myofilaments |
front 81 During muscle contraction, myosin cross bridges attach to which active sites?
| back 81 actin filaments |
front 82 Which of the following surrounds the individual muscle cell?
| back 82 endomysium |
front 83 The term aponeurosis refers to ________.
| back 83 a sheetlike indirect attachment to a skeletal element |
front 84 The oxygen-binding protein found in muscle cells is ________.
| back 84 myoglobin |
front 85 The contractile units of skeletal muscles are ________.
| back 85 myofibrils |
front 86 What is the functional unit of a skeletal muscle called?
| back 86 a sarcomere |
front 87 What is the functional role of the T tubules?
| back 87 enhance cellular communication during muscle contraction |
front 88 What is the role of calcium ions in muscle contraction?
| back 88 bind to regulatory sites on troponin to remove contraction inhibition |
front 89 During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.
| back 89 lactic acid |
front 90 When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?
| back 90 refractory period |
front 91 In an isotonic contraction, the muscle ________.
| back 91 changes in length and moves the "load" |
front 92 The muscle cell membrane is called the ________.
| back 92 sarcolemma |
front 93 Which of the following is the correct sequence of events for muscle contractions?
| back 93 C |
front 94 The giant protein titin maintains the organization of the ________ assisting in muscle stretching.
| back 94 A band |
front 95 Which of the following statements is true?
| back 95 Skeletal muscle cells are long and cylindrical with many nuclei. |
front 96 An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________.
| back 96 glycolysis |
front 97 Muscle tone is ________.
| back 97 a state of sustained partial contraction |
front 98 After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?
| back 98 acetylcholinesterase destroying the ACh |
front 99 Which of the following statements is most accurate?
| back 99 Muscle tension remains relatively constant during isotonic contraction. |
front 100 Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, ________.
| back 100 no muscle tension could be generated |
front 101 What part of the sarcolemma contains acetylcholine receptors?
| back 101 motor end plate |
front 102 Gary was injured in an automobile accident that severed the motor neurons innervating his quadriceps. Even though he has had extensive physical therapy, he is still suffering muscle atrophy. Why is the therapy not working?
| back 102 B |
front 103 Aaron arrived at the hospital with the following symptoms: drooping eyelids; fatigue and weakness of his muscles; and difficulty talking, breathing, and swallowing. What was his diagnosis?
| back 103 Myasthenia gravis |
front 104 The nurse encourages the patient to do his own activities of daily living such as bathing, eating, dressing, and toileting activities. How do these activities promote physical conditioning?
| back 104 The contraction of the muscles in these activities helps maintain the shape, size, and strength of muscles, as well as joint mobility. |
front 105 A contraction in which the muscle does not shorten but its tension increases is called isometric contraction.
| back 105 T |
front 106 Muscle cells store more creatine phosphate than ATP resulting in the muscle having a reserve source of energy.
| back 106 T |
front 107 The connective tissue sheaths of skeletal muscle, in order from internal to external, are the ________.
| back 107 endomysium, perimysium, and epimysium |
front 108 Choose the FALSE statement.
| back 108 Skeletal muscle cells use creatine phosphate instead of ATP to do work. |
front 109 The smallest contractile unit of a muscle fiber is ________.
| back 109 The Sarcomere |
front 110 Thick myofilaments are made of ________.
| back 110 myosin |
front 111 The distance between Z discs ________ during muscle contraction.
| back 111 decreases |
front 112 The sliding filament model of contraction states that ________.
| back 112 during contraction the thin myofilaments slide past the thick myofilaments so that the actin and myosin myofilaments overlap to a greater degree |
front 113 The first step toward generating a skeletal muscle contraction is ________.
| back 113 stimulation of the muscle by a nerve ending |
front 114 A muscle that is lengthening while it produces tension is performing a(an) ________ contraction.
| back 114 eccentric |
front 115 When muscle cells break down glucose to generate ATP under oxygen deficient conditions, they will form ________.
| back 115 lactic acid |
front 116 Slow oxidative muscle fibers are best suited for ________.
| back 116 running a marathon |
front 117 Which of the following is TRUE?
| back 117 Skeletal muscle fibers contain sarcomeres; smooth muscle fibers do not. |
front 118 Binding of calcium to calmodulin is a step in excitation-contraction coupling of ________ cells.
| back 118 smooth muscle |
front 119 A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane.
| back 119 T |
front 120 Which of the following is false or incorrect?
| back 120 A nerve impulse occurs if the excitatory and inhibitory effects are equal. |
front 121 In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier.
| back 121 T |
front 122 Which of the following is NOT a type of circuit?
| back 122 pre-discharge circuits |
front 123 Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.
| back 123 T |
front 124 Smooth muscles relax when intracellular Ca2+ levels drop but may not cease contractions.
| back 124 T |
front 125 The mechanism of contraction in smooth muscle is different from skeletal muscle in that ________.
| back 125 the site of calcium regulation differs |
front 126 Which of the following is true about smooth muscle contraction?
| back 126 Certain smooth muscle cells can actually divide to increase their numbers. |
front 127 Smooth muscle is characterized by all of the following except ________.
| back 127 there are more thick filaments than thin filaments |
front 128 Of the following muscle types, which has only one nucleus, no sarcomeres, and rare gap junctions?
| back 128 multiunit smooth muscle |
front 129 Which of the following statements is false or incorrect?
| back 129 Cardiac muscle fibers depend mostly on anaerobic cellular respiration to generate ATP. |
front 130 Cells of unitary smooth muscle are found in the longitudinal and circular muscle layers of the intestine.
| back 130 T |
front 131 Which of the following describes the cells of unitary smooth muscle?
| back 131 They exhibit spontaneous action potentials. |
front 132 What special feature of smooth muscle allows it to stretch without immediately resulting in a strong contraction?
| back 132 stress-relaxation response |
front 133 Isometric contraction leads to movement of a load.
| back 133 F |
front 134 Cardiac muscle makes most of its ATP via anaerobic pathways.
| back 134 F |
front 135 Duchenne muscular dystrophy could theoretically be cured if a technique was developed that would _________.
| back 135 none of the above |
front 136 Which muscle cells have the greatest ability to regenerate?
| back 136 smooth |
front 137 Cardiac muscle has a limited regenerative capacity.
| back 137 T |
front 138 Smooth muscles are able to regenerate throughout life.
| back 138 T |
front 139 Which functional group has the major responsibility for producing a specific movement?
| back 139 agonists |
front 140 What type of muscle assists an agonist by causing a like movement or by stabilizing a joint over which an agonist acts?
| back 140 a synergist |
front 141 Muscles are only able to pull, they never push.
| back 141 T |
front 142 Muscles that help maintain upright posture are fixators.
| back 142 T |
front 143 Muscles that help to maintain posture are often called synergists.
| back 143 F |
front 144 Which of the following muscles is named for its origin and insertion?
| back 144 sternocleidomastoid |
front 145 When the term biceps, triceps, or quadriceps forms part of a muscle's name, what does it tell you about the muscle?
| back 145 The muscle has two, three, or four origins, respectively. |
front 146 Axon diameter and degree of myelination determine nerve impulse conduction velocity.
| back 146 T |
front 147 The action potential is caused by permeability changes in the plasma membrane.
| back 147 T |
front 148 A pair of tweezers is a good example of a second-class lever.
| back 148 F |
front 149 Both first- and second-class levers operate at a mechanical disadvantage.
| back 149 F |
front 150 Although all skeletal muscles have different shapes, the fascicle arrangement of each muscle is exactly the same.
| back 150 F |
front 151 Regardless of type, all levers follow the same basic principle: effort farther than load from fulcrum = mechanical advantage; effort nearer than load to fulcrum = mechanical disadvantage.
| back 151 T |
front 152 The arrangement of a muscle's fascicles determines its range of motion and power.
| back 152 T |
front 153 Muscle power does not depend on the direction of the fascicles.
| back 153 T |
front 154 Diffusion movement always occurs from areas of greater to areas of lesser concentration.
| back 154 T |
front 155 In their resting state, all body cells exhibit a resting membrane potential ranging from -50 to about +50 millivolts.
| back 155 F |
front 156 Which cell organelle provides the majority of the ATP needed by the cell to carry out its metabolic reactions?
| back 156 Mitochondria |
front 157 Microfilaments are thin strands of the contractile protein myosin.
| back 157 F |
front 158 The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place.
| back 158 F |
front 159 During depolarization, the inside of the neuron's membrane becomes less negative.
| back 159 T |
front 160 Strong stimuli cause the amplitude of action potentials generated to increase.
| back 160 F |
front 161 A postsynaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons.
| back 161 T |
front 162 Large-diameter nerve fibers conduct impulses much faster than small-diameter fibers.
| back 162 T |
front 163 The major role of the sarcoplasmic reticulum is to regulate ________.
| back 163 intracellular levels of Ca2+ |
front 164 The response of a motor unit to a single action potential of its motor neuron is called ________.
| back 164 a muscle twitch |
front 165 The force of a muscle contraction is NOT affected by __________.
| back 165 the amount of ATP stored in the muscle cells |
front 166 ________ are the muscles primarily responsible for producing a particular movement.
| back 166 Agonists |
front 167 What is a muscle that provides the major force for producing a specific movement called?
| back 167 an agonist |
front 168 Which generalization concerning movement by skeletal muscles is not true?
| back 168 During contraction the two articulating bones move equally. |
front 169 Which of the following is NOT used as a criterion for naming muscles?
| back 169 whether the muscle is controlled by the involuntary or voluntary nervous system |
front 170 Which of the following muscles is named for its action?
| back 170 levator labii superioris |
front 171 The names of muscles often indicate the action of the muscle. What does the term levator mean?
| back 171 The muscle elevates and/or adducts a region. |
front 172 A muscle that opposes, or reverses, a particular movement is a(n) ________.
| back 172 antagonist |
front 173 Which of these is not a way of classifying muscles?
| back 173 the type of muscle fibers |
front 174 A patient is admitted to the hospital with exacerbation of multiple sclerosis (MS). She asks the nurse "Why did this have to happen to me again? I was doing so well." Why are some forms of MS characterized by periods of remission and exacerbation?
| back 174 The axons are not damaged; growing numbers of sodium channels appear spontaneously in the demyelinated fibers, allowing conduction to resume. |
front 175 What does the central nervous system use to determine the strength of a stimulus?
| back 175 frequency of action potentials |
front 176 Immediately after an action potential has peaked, which cellular gates open?
| back 176 potassium |
front 177 Which of the following is true about the movement of ions across excitable living membranes?
| back 177 Sodium gates in the membrane can open in response to electrical potential changes. |
front 178 What type of stimulus is required for an action potential to be generated?
| back 178 a threshold level depolarization |
front 179 Which of the following is NOT true of an electrical synapse?
| back 179 They are specialized for release and reception of chemical neurotransmitters. |
front 180 Which of the following circuit types is involved in the control of rhythmic activities such as the sleep-wake cycle, breathing, and certain motor activities (such as arm swinging when walking)?
| back 180 reverberating circuits |
front 181 An impulse from one nerve cell is communicated to another nerve cell via the ________.
| back 181 synapse |
front 182 An inhibitory postsynaptic potential (IPSP) is associated with ________.
| back 182 hyperpolarization |
front 183 Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane?
| back 183 A single type of channel will open, permitting simultaneous flow of sodium and potassium. |
front 184 Caveolae are closely associated with all of the following except ________.
| back 184 enzymes involved in cell metabolism |
front 185 Which of the following statements is correct regarding net diffusion?
| back 185 The greater the concentration gradient, the faster the rate. |
front 186 What is a membrane potential?
| back 186 a voltage or electrical charge across the plasma membrane |
front 187 Which of the following is NOT a characteristic of peroxisomes?
| back 187 They contain powerful enzymes called acid hydrolases. |
front 188 Which of the following is FALSE regarding the membrane potential?
| back 188 The resting membrane potential is maintained by solely by passive transport processes. |
front 189 Which of the following is NOT a function of the smooth endoplasmic reticulum?
| back 189 protein synthesis in conjunction with ribosomes |
front 190 Most skeletal muscles of the body act in ________.
| back 190 third-class lever systems |
front 191 If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________.
| back 191 the impulse would spread bidirectionally |
front 192 In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________.
| back 192 negatively charged and contains less sodium |
front 193 A second nerve impulse cannot be generated until ________.
| back 193 the membrane potential has been reestablished |
front 194 Which of the following is not true of graded potentials?
| back 194 They increase amplitude as they move away from the stimulus point. |
front 195 When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.
| back 195 generator potential |
front 196 Saltatory conduction is made possible by ________.
| back 196 the myelin sheath |
front 197 Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?
| back 197 voltage-gated channel |
front 198 The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.
| back 198 absolute refractory period |
front 199 Local anesthetics block voltage-gated Na+ channels, but they do not block mechanically gated ion channels. Sensory receptors for touch (and pressure) respond to physical deformation of the receptors, resulting in the opening of specific mechanically gated ion channels. Why does injection of a local anesthetic into a finger still cause a loss of the sensation of touch from the finger?
| back 199 Touch stimulation of this sensory receptor will open the mechanically gated ion channels, but action potentials are still not initiated because propagation of an action potential requires the opening of voltage-gated Na+ channels. |
front 200 In multiple sclerosis, the cells that are the target of an autoimmune attack are the _________.
| back 200 oligodendrocytes |
front 201 Which of the following movements demonstrates a first-class lever?
| back 201 raising your head up off your chest |
front 202 Which type of lever is demonstrated by using scissors?
| back 202 a first-class lever |
front 203 What is the major factor controlling how levers work?
| back 203 the difference in the positioning of the effort, load, and fulcrum |
front 204 What is the main factor that determines the power of a muscle?
| back 204 the total number of muscle cells available for contraction |
front 205 What are the levers that operate at a mechanical advantage called?
| back 205 power levers |
front 206 First-class levers ________.
| back 206 in the body can operate at a mechanical advantage or mechanical disadvantage, depending on specific location |
front 207 If a lever operates at a mechanical disadvantage, it means that the ________.
| back 207 load is far from the fulcrum and the effort is applied near the fulcrum |
front 208 If L = load, F = fulcrum, and E = effort, what type of lever system is described as LEF?
| back 208 third-class lever |
front 209 Which of the following would NOT diffuse through the plasma membrane by means of simple diffusion?
| back 209 glucose |
front 210 Which of the following describes the plasma membrane?
| back 210 the phospholipid bilayer surrounding the cell |
front 211 Which of the following is a difference between primary and secondary active transport?
| back 211 In primary active transport, the transport protein gets phosphorylated; in secondary active transport, the transport protein is not phosphorylated. |