Bio 2780 exam 2

11) The largest and most numerous of the glial cells in the central nervous system are the A) astrocytes. B) Schwann cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

A) astrocytes.

9) The glial cells responsible for maintaining the blood-brain barrier are the A) astrocytes. B) Schwann cells. C) microglia. D) ependymal cells. E) satellite cells.

A) astrocytes.

33) A few spiders produce a venom that is a calcium-channel blocker. Where would this venom have on nerve impulse transmission? A) at the axon terminal B) at the axon hillock C) along the dendrite D) along the cell body membrane E) at the postsynaptic membrane

A) at the axon terminal

3) In general, the nervous system A) controls only conscious activities. B) is fast acting. C) is long lasting. D) responds to changes in the external environment only. E) is one of the simplest organ systems.

B) is fast acting.

33) The specialized sarcolemma that contains acetylcholine receptors is the A) synaptic knob. B) motor end plate. C) motor unit. D) synaptic cleft. E) I band.

B) motor end plate

35) Neurotransmitters that cause skeletal muscle contraction are normally stored in A) myofibrils. B) motor neuron axon terminals. C) motor units. D) motor end plates. E) actin.

B) motor neuron axon terminals.

15) Myofibrils are made primarily of A) actin and myosin. B) epimysium. C) ATP and ADP. D) troponin. E) tropomyosin.

A) actin and myosin.

2) The brain and spinal cord comprise the A) autonomic nervous system. B) peripheral nervous system. C) central nervous system. D) efferent nervous system. E) afferent nervous system.

C) central nervous system.

4) The part of the peripheral nervous system that brings information to the central nervous system is the A) motor division. B) afferent division. C) efferent division. D) autonomic division. E) somatic division.

B) afferent division.

10) The region of a sarcomere containing myosin, going from one end of the myosin molecules to the other end of the myosin molecules, is the A) Z line. B) M line. C) H band. D) A band. E) I band.

D) A band.

36) The stiffness that occurs at death, when actin and myosin molecules stay linked to each other in a contracted state, is due to a lack of A) cAMP. B) DNA. C) RNA. D) ATP. E) tRNA

D) ATP.

7) The ________ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity. A) central B) autonomic C) somatic D) collateral E) ganglionic

B) autonomic

38) Which of the following is one of the steps that ends a contraction? A) Sarcoplasmic reticulum absorbs sodium ions. B) Acetylcholine binds to receptors on the sarcolemma. C) Calcium ions bind to troponin. D) Acetylcholine is broken down by acetylcholinesterase. E) An action potential spreads across the entire surface of the muscle fiber.

D) Acetylcholine is broken down by acetylcholinesterase.

2) Which of the following statements describes how muscles help maintain homeostasis? A) The contractions of skeletal muscles pull on tendons and move elements of the skeleton. B) Skeletal muscles are responsible for guarding the openings of the digestive and urinary tracts. C) Skeletal muscles are responsible for the pumping action of the heart. D) Skeletal muscles support the weight of some internal organs. E) Skeletal muscle contractions help maintain body temperature.

E) Skeletal muscle contractions help maintain body temperature.

18) Neurons that have two or more dendrites and a single axon extending away from the cell body are called A) polypolar. B) unipolar. C) bipolar. D) tripolar. E) multipolar

E) multipolar

41) After death, rigor mortis lasts until A) ATP is produced. B) T-tubules recapture calcium ions. C) sodium ions are released by the sarcoplasmic reticulum. D) sarcomeres lengthen. E) myofilaments are broken down.

E) myofilaments are broken down.

5) All of the nervous tissue outside of the central nervous system comprises the ________ nervous system. A) somatic B) autonomic C) sympathetic D) central E) peripheral

E) peripheral

32) The ________ contains vesicles filled with acetylcholine. A) axon terminal B) motor end plate C) neuromuscular junction D) synaptic cleft E) transverse tubule

A) axon terminal

31) The enzyme acetylcholinesterase causes acetylcholine to A) break down. B) synthesize. C) bond to actin. D) be secreted. E) form cross-bridges.

A) break down.

27) Opening of voltage-gated sodium channels in the membrane of a neuron results in A) depolarization. B) repolarization. C) hyperpolarization. D) increased negative charge inside the membrane. E) myelination.

A) depolarization.

2) The nervous system A) is ideal for crisis management. B) communicates mainly by the release of hormones. C) has effects that are very long-lived. D) is regulated mainly by positive feedback. E) does not rely on the binding of receptors to target cells.

A) is ideal for crisis management.

45) Calcium ions are released from the sarcoplasmic reticulum during the ________ phase of contraction. A) latent B) contraction C) twitch D) relaxation E) recovery

A) latent

23) The all-or-none principle states that A) all stimuli will produce identical action potentials. B) all stimuli great enough to bring the membrane to threshold will produce identical action potentials. C) the greater the magnitude of the stimuli, the greater the intensity of the action potential. D) only sensory stimuli can activate action potentials. E) only motor stimuli can activate action potentials.

B) all stimuli great enough to bring the membrane to threshold will produce identical action potentials.

21) Steroid hormones A) are proteins. B) are structurally similar to cholesterol. C) are the largest class of hormones. D) include pancreatic hormones. E) are secreted by the hypothalamus and pituitary gland.

B) are structurally similar to cholesterol.

18) The active sites on actin molecules are usually covered up by other molecules. What is the critical material required to uncover the active sites on the actin molecules that will then bind to myosin heads? A) ATP B) calcium C) oxygen D) vitamin A E) titin

B) calcium

28) Which statement is true regarding action potential propagation? A) In salutatory conduction, the myelin is composed of fat, which insulates the axon membrane against sodium ion flow across the membrane. B) Continuous propagation results in one graded potential producing multiple action potentials. C) The action potential will die out along the axon if another graded potential does not occur. D) All voltage-gated channels along the axon open at the same time, allowing sodium to flow in simultaneously. E) The active transport of sodium and potassium through sodium-potassium ion pumps causes depolarization of the axon membrane.

A) In salutatory conduction, the myelin is composed of fat, which insulates the axon membrane against sodium ion flow across the membrane.

48) During which phase is the stimulus frequency so high that the relaxation phase is eliminated? A) complete tetanus B) a twitch C) incomplete tetanus D) recovery E) recruitment

A) complete tetanus

20) Peptide hormones are A) composed of chains of amino acids. B) released by the reproductive organs. C) derived from arachidonic acid. D) lipids. E) chemically related to cholesterol.

A) composed of chains of amino acids.

8) A muscle ________ contains a sarcolemma, sarcoplasm, myofilaments, and myofibrils. A) fiber B) intercalated disc C) T-tubule D) myofibril E) motor end plate

A) fiber

39) The ________ is the layer of the meninges that is in direct contact with the surface of the brain. A) pia mater B) subarachnoid space C) dura mater D) epidural space E) arachnoid

A) pia mater

31) Identify the correct sequence of steps in the generation of an action potential. 1. Activation of sodium channels and rapid depolarization 2. Inactivation of sodium channels and activation of potassium channels 3. Depolarization to threshold 4. Closing of potassium channels A) 1, 3, 4, 2 B) 3, 1, 2, 4 C) 4, 3, 2, 1 D) 1, 3, 2, 4 E) 3, 1, 4, 2

B) 3, 1, 2, 4

47) Which statement regarding the relaxation phase of a muscle twitch is true? A) The phase begins at stimulation and typically lasts about two milliseconds. B) Muscle tension falls to resting levels. C) The action potential sweeps across the sarcomere during this period. D) Tension rises to a peak. E) Cross-bridges are interacting with active sites on actin filaments throughout this period

B) Muscle tension falls to resting levels.

14) The neurilemma of axons in the peripheral nervous system is the outer layer of A) astrocytes. B) Schwann cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

B) Schwann cells.

32) Adrenergic synapses release the neurotransmitter A) acetylcholine. B) norepinephrine. C) dopamine. D) serotonin. E) GABA

B) norepinephrine.

4) A sheath of connective tissue surrounding a bundle of striated muscle fibers is called A) endomysium. B) perimysium. C) sarcolemma. D) epimysium. E) sarcoplasmic reticulum.

B) perimysium.

5) Muscle fascicles are separated by A) endomysium. B) perimysium. C) epimysium. D) sarcolemma. E) periosteum.

B) perimysium.

9) The area between Z lines is the A) sarcolemma. B) sarcomere. C) sarcoplasmic reticulum. D) myofibril. E) myofilament

B) sarcomere.

12) The terminal cisternae are structural features of the A) myofilaments. B) sarcoplasmic reticula. C) myofibrils. D) I bands. E) sarcolemma.

B) sarcoplasmic reticula.

24) The resting potential of a neuron is A) 0 mV. B) +10 mV. C) -70 mV. D) -10 mV. E) +70 mV.

C) -70 mV

7) Each myofibril consists of approximately ________ sarcomeres. A) 10 B) 500 C) 10,000 D) 100,000 E) 2-3 million

C) 10,000

50) Choose the correct statement regarding motor units. A) Muscle fibers of each motor unit are not mingled with those of other motor units. B) During a sustained contraction, all motor units are activated simultaneously. C) A motor neuron may control only two or three muscle fibers of the eye muscle(s). D) When muscles contract for sustained periods, maximal tension is maintained. E) Most motor neurons control fewer than five muscle fibers.

C) A motor neuron may control only two or three muscle fibers of the eye muscle(s).

11) The area of the sarcomere that is the light region between two successive A-bands is the A) Z line. B) M line. C) I band. D) myofibril. E) H band.

C) I band.

29) During continuous conduction, A) action potentials move in all directions along an axon. B) action potentials occur at successive nodes along the length of the stimulated axon. C) local currents depolarize adjacent areas of membrane so that action potentials continue along the membrane. D) the action potential starts at the beginning of the neuronal pathway and continues form neuron to neuron. E) local potentials produce a continuous outward flow of potassium ions.

C) local currents depolarize adjacent areas of membrane so that action potentials continue along the membrane.

46) Which of the following occurs as a result of motor units in a particular muscle being always active, even though their contractions do not produce enough movement to cause contraction? A) treppe B) tetany C) muscle tone D) fatigue E) a twitch

C) muscle tone

12) The myelin sheaths that surround the axons of some of the neurons in the CNS are formed by A) astrocytes. B) Schwann cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

C) oligodendrocytes.

1) Peripheral structures sensitive to the presence of hormones are called A) exocrine cells. B) first messengers. C) target cells. D) second messengers. E) G-proteins.

C) target cells.

14) Tropomyosin strands are held in position by which of the following? A) actin molecules B) myosin molecules C) troponin molecules D) ATP molecules E) calcium ions

C) troponin molecules

47) Which spinal cord structure(s) contains the axons of CNS motor neurons that control muscles and glands? A) anterior gray commissure B) white column C) ventral roots D) dorsal roots E) ventral horns

C) ventral roots

34) Place these steps of muscle contraction in the correct order. 1. Action potential is generated along the sarcolemma 2. Nerve impulse arrives at synapse 3. Calcium is released into muscle cell cytoplasm 4. Acetylcholine is produced 5. Actin and myosin molecules continuously cross-link, with actin molecules being pulled inward A) 2, 3, 4, 1, 5 B) 4, 2, 1, 5, 3 C) 1, 2, 4, 3, 5 D) 2, 4, 1, 3, 5 E) 1, 2, 4, 5, 3

D) 2, 4, 1, 3, 5

44) The entire spinal cord is divided into ________ segments. A) 5 B) 12 C) 25 D) 31 E) 35

D) 31

15) Clusters of rough endoplasmic reticulum and free ribosomes are known as A) neurofilaments. B) neurofibrils. C) synapses. D) Nissl bodies. E) microglia.

D) Nissl bodies.

8) Most neurons in the brain are A) bipolar. B) unipolar. C) anaxonic. D) multipolar. E) tripolar.

D) multipolar.

48) When a cerebrospinal fluid specimen is needed for testing, the specimen is removed by needle from the L3-L4 interspace area of the vertebral column. Why? A) There are no spaces between the other areas of the vertebral column. B) There is a higher pressure within the subarachnoid space at that point, so it is easier to obtain a specimen. C) There are no spinal nerves located in that area. D) There would be no possible damage to the spinal cord itself when the needle is inserted into the space. E) The space where the needle is inserted is larger than anywhere else along the vertebral column.

D) There would be no possible damage to the spinal cord itself when the needle is inserted into the space.

35) Which of the following neurotransmitters usually depolarizes postsynaptic neurons? A) serotonin B) dopamine C) GABA D) acetylcholine E) monoamine oxidase

D) acetylcholine

13) The striated appearance of skeletal muscle results from A) the transverse tubule pattern. B) the sarcoplasmic reticulum. C) cisternae placement. D) actin and myosin arrangement. E) the perimysium arrangement.

D) actin and myosin arrangement.

39) In response to action potentials arriving from the transverse tubules, the sarcoplasmic reticulum releases A) acetylcholine. B) sodium ions. C) potassium ions. D) calcium ions. E) acetylcholinesterase.

D) calcium ions.

10) The branching structures that, together with the cell body, are sensitive to chemical, mechanical, or electrical stimulation are called A) axons. B) Nissl bodies. C) synapses. D) dendrites. E) neurofibrils.

D) dendrites.

17) The skeletal muscles store calcium ions in the terminal cisternae of the A) sarcolemma. B) sarcomere. C) sarcosome. D) sarcoplasmic reticulum. E) sarcoplasm.

D) sarcoplasmic reticulum.

1) Which of the following is a function of the efferent division of the nervous system? A) providing sensation of the internal and external environments B) integrating sensory information C) coordinating voluntary and involuntary activities D) sending signals to muscles E) regulating or controlling peripheral structures and systems

D) sending signals to muscles

38) Which of the following contains a delicate network of collagen and elastin fibers through which cerebrospinal fluid circulates? A) epidural space B) dural sinus C) arachnoid villi D) subarachnoid space E) pia mater

D) subarachnoid space

20) Bundles of CNS axons that share a common origin, destination, and function are called A) the cortex. B) centers. C) nuclei. D) tracts. E) ganglia.

D) tracts

36) Which of the following is the correct order of events that occur at a cholinergic synapse? 1. Extracellular calcium enters the axon terminal, triggering the exocytosis of acetylcholine. 2. Acetylcholine is removed by acetylcholinesterase. 3. Acetylcholine binds to receptors and depolarizes the postsynaptic membrane. 4. Axon terminal depolarizes. A) 2, 3, 1, 4 B) 1, 4, 3, 2 C) 4, 1, 2, 3 D) 3, 4, 1, 2 E) 4, 1, 3, 2

E) 4, 1, 3, 2

1) Which statement regarding skeletal muscle is true? A) Skeletal muscles are directly, but not indirectly, attached to bones. B) Skeletal muscles do not contain connective tissue. C) Skeletal muscles do not maintain body temperature. D) Skeletal muscles do not contain nervous tissue. E) Skeletal muscles contain blood vessels.

E) Skeletal muscles contain blood vessels.

3) A layer of collagen fibers that surrounds an entire muscle is called A) endomysium. B) perimysium. C) sarcolemma. D) sarcomere. E) epimysium.

E) epimysium.

30) Acetylcholinesterase is found within the A) nucleus. B) sarcolemma. C) myofibril. D) sarcomere. E) synaptic cleft.

E) synaptic cleft.

44) A single stimulus-contraction-relaxation sequence in a muscle fiber is known as a(n) A) incomplete tetanus. B) latent period. C) complete tetanus. D) summation. E) twitch.

E) twitch.

6) The ________ division of the nervous system brings sensory information to the central nervous system. A) afferent B) descending C) efferent D) motor E) spinal

A) afferent

21) Interneurons A) are found only in the central nervous system. B) carry only sensory impulses. C) carry only motor impulses. D) only connect motor neurons to other motor neurons. E) are found between neurons and their effectors.

A) are found only in the central nervous system.

37) You have been diagnosed with the demyelinating disease called multiple sclerosis. The areas of damage seem to be centered within the spinal cord. The demyelinated areas are most probably within the A) ascending and/or descending tracts. B) dorsal or ventral horns. C) central canal. D) dorsal root ganglia. E) gray commissure.

A) ascending and/or descending tracts.

4) Generally, the actions of hormones A) tend to be less widespread than actions of the nervous system. B) can produce complex changes in physical structure and physiological changes. C) are faster to react than the nervous system. D) are shorter-lasting than the actions of the nervous system. E) do not affect homeostasis.

B) can produce complex changes in physical structure and physiological changes.

25) Changes in the membrane potential that cannot spread far from the site of stimulation are called A) threshold. B) graded potentials. C) refractories. D) hyperpolarizations. E) action potentials.

B) graded potentials.

16) Skeletal muscle fibers differ from "typical cells" in that these muscle fibers A) lack a plasma membrane. B) have many nuclei. C) are very small. D) lack mitochondria. E) contain endoplasmic reticulum.

B) have many nuclei

41) The projections of gray matter extending through the white matter toward the outer surface of the spinal cord are called A) wings. B) horns. C) pyramids. D) fibers. E) tracts.

B) horns.

30) A stimulus that opens gated potassium ion channels, moving the membrane voltage value below the resting potential value, results in which of the following? A) repolarization B) hyperpolarization C) depolarization D) refraction E) summation

B) hyperpolarization

40) As a skeletal muscle contraction is initiated, acetylcholine binding alters the motor end plate membrane's permeability to A) acetylcholinesterase. B) sodium ions. C) calcium ions. D) chloride ions. E) potassium ions.

B) sodium ions.

40) Head injuries that damage cerebral blood vessels are serious conditions because A) they could cause severe pain. B) the blood could compress and distort the relatively soft tissues of the brain. C) epicardial tissue will be affected. D) the venous sinus will not drain. E) pathways will be blocked.

B) the blood could compress and distort the relatively soft tissues of the brain.

19) What is the function of the transverse tubule? A) the storage of calcium ions B) to transmit electrical impulses to the cell's interior C) to store sodium ions D) to allow cross-bridge attachment E) to produce myofibrils

B) to transmit electrical impulses to the cell's interior

22) Most neurons lack centrioles. This observation explains A) why neurons grow such long axons. B) why such neurons cannot divide through mitosis. C) the conducting ability of neurons. D) the ability of neurons to communicate with each other. E) the longevity of neurons.

B) why such neurons cannot divide through mitosis.

52) Which statement regarding isometric contractions is true? A) Tension rises during a contraction. B) The skeletal muscle's length changes. C) The tension produced never exceeds the load. D) Tension remains at a constant level until relaxation occurs. E) Examples are walking and running.

C) The tension produced never exceeds the load.

19) The hormone leptin is secreted by (the) A) pancreas. B) kidneys. C) adipose tissue. D) hypothalamus. E) anterior pituitary.

C) adipose tissue.

17) Neurons that have one axon and one dendrite with the cell body between them are called A) polypolar. B) unipolar. C) bipolar. D) tripolar. E) multipolar

C) bipolar.

16) Branches that sometimes occur along the length of an axon are called A) action potentials. B) synaptic knobs. C) collaterals. D) hillocks. E) synapse.

C) collaterals.

19) Which neuroglial cells produce CSF in some regions of the brain? A) microglia B) Schwann cells C) ependymal cells D) oligodendrocytes E) astrocytes

C) ependymal cells

43) Enlargements of the spinal cord occur A) near the posterior median sulcus. B) adjacent to the anterior median fissure. C) in the cervical and lumbar regions. D) in the thoracic region of the spinal cord. E) in the cervical and thoracic regions.

C) in the cervical and lumbar regions.

26) Saltatory conduction A) occurs only if the myelin sheath is continuous. B) occurs only if nodes of Ranvier are lacking. C) is faster than conduction on an unmyelinated axon. D) produces a stronger action potential. E) occurs at the synapse.

C) is faster than conduction on an unmyelinated axon.

53) Why do individual muscle twitches have to be added together, as in summation or tetanus? A) Only added twitches produce any muscle contraction: A fiber undergoing a muscle twitch does not contract at all. B) There has to be a critical mass of muscle twitches for calcium to be released into the muscle cell. C) Not enough acetylcholine will be produced for contraction without multiple twitches. D) Multiple twitches add up to an increase in muscle fiber tension, which increases the strength of the muscle. E) Not enough ATP is generated by one muscle twitch.

D) Multiple twitches add up to an increase in muscle fiber tension, which increases the strength of the muscle.

45) The gray matter of the spinal cord is dominated by A) tracts. B) columns. C) meninges. D) cell bodies of neurons and glial cells. E) blood vessels.

D) cell bodies of neurons and glial cells.

34) Multiple areas of the brain can regulate breathing at the same time by stimulating the diaphragm for contraction. This activity is best explained by A) saltatory conduction. B) divergent neuronal pools. C) linear neuronal pools. D) convergent neuronal pools. E) the all-or-none principle.

D) convergent neuronal pools.

49) Regarding muscle fiber elongation, A) many active mechanisms exist for muscle fiber elongation. B) muscle contraction is passive; whereas, elongation is active. C) opposing muscle movements are not a factor. D) gravity may help lengthen a muscle fiber after elongation. E) elastic forces are generated where a muscle fiber elongates.

D) gravity may help lengthen a muscle fiber after elongation

42) Axons that cross from one side of the spinal cord to the other are found in the A) anterior white columns. B) lateral gray horns. C) posterior gray horns. D) gray commissures. E) posterior white columns.

D) gray commissures.

43) Which of the following occurs when tension production rises to a peak and very brief periods of relaxation occur? A) resting period B) latency C) tension plateau D) incomplete tetanus E) complete tetanus

D) incomplete tetanus

13) Small phagocytic glial cells, which are derived from white blood cells, are called A) astrocytes. B) Schwann cells. C) oligodendrocytes. D) microglia. E) ependymal cells.

D) microglia.

6) Regarding a skeletal muscle fiber, wherever a T-tubule encircles a myofibril, the tubule is tightly bound to A) the nucleus. B) the sarcolemma. C) the endomysium. D) the sarcoplasmic reticulum. E) thick filaments.

D) the sarcoplasmic reticulum.

37) Upon the nerve impulse arriving at the axon terminal, A) active sites on actin are exposed. B) active sites on myosin are exposed. C) actin heads will bind to myosin. D) muscle relaxation occurs. E) acetylcholine is released.

E) acetylcholine is released.

51) Muscle cells A) actively lengthen. B) generate compression. C) possess a mechanism that regulates the tension amount by changing the number of contracting sarcomeres. D) vary tension production based on the amount of sodium ions bound to actin. E) can only contract.

E) can only contract.

46) In adults, the spinal cord usually extends to which level? A) tenth thoracic vertebra B) first sacral vertebra C) seventh cervical vertebra D) fourth or fifth lumbar vertebra E) first or second lumbar vertebra

E) first or second lumbar vertebra

18) In the simplest case, endocrine activity may be controlled by changes in the extracellular fluid composition called ________ stimuli. A) hormonal B) cellular C) neural D) membrane E) humoral

E) humoral

49) If the dorsal root of a spinal nerve is severed, A) motor control of skeletal muscles would be impaired. B) motor control of visceral organs would be impaired. C) the spinal cord would not be able to process information at that level. D) the brain would not be able to communicate with that level of the spinal cord. E) incoming sensory information would be disrupted.

E) incoming sensory information would be disrupted.

3) The endocrine system A) releases neurotransmitters into the bloodstream for distribution throughout the body. B) is regulated mainly by positive feedback. C) produces effects that last for seconds or minutes. D) is not involved in homeostasis. E) relies on the release of chemicals that bind to target cells.

E) relies on the release of chemicals that bind to target cells.

42) Botulism A) is the result of an attack on acetylcholine receptors by the immune system. B) is usually tied to a genetic predisposition. C) is a viral illness. D) results from the loss of acetylcholine receptors at the motor end plate. E) results from a bacterial toxin that prevents the release of acetylcholine at the axon terminals.

E) results from a bacterial toxin that prevents the release of acetylcholine at the axon terminals.