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53 Cards in this Set
- Front
- Back
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During muscle contraction, myosin cross bridges attach to binding sites on the
a. thin filaments b. thick filaments c. Z-discs d. T-tubules |
a. thin filaments
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Which of the following proteins binds Ca2+ during skeletal muscle contraction?
a. tropomyosin b. actin c. tropinin d. myosin |
c. tropinin
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In resting skeletal muscle, the function of tropomyosin is to:
a. bind Ca2+ b. release Ca2+ from the sarcoplasmic reticulum c. block the access of myosin heads to their binding sites on the actin thin filaments d. connect the thin filaments to the Z-disc |
c. block the access of myosin heads to their binding sites on the actin thin
filaments |
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The function of the transverse tubules in skeletal muscle is to:
a. conduct the action potential down into the cell, causing release of Ca2+ from the sarcoplasmic reticulum b. conduct nutrients down into the cell c. store the Ca2+ used for muscle contraction d. create a graded end plate potential |
a. conduct the action potential down into the cell, causing release of Ca2+ from
the sarcoplasmic reticulum |
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Which of the following statements concerning the sarcomere is FALSE?
a. The sarcomere is the functional unit of skeletal muscle. b. Each myofibril is formed from hundreds of identical sarcomeres attached end to end. c. The sarcomere encompasses the region between two Z-discs. d. Sarcomeres are invaginations of the sarcolemma. |
d. Sarcomeres are invaginations of the sarcolemma.
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In skeletal muscle fibers, the cytosolic Ca2+ concentration is highest:
a. in relaxed muscle b. during the skeletal muscle action potential c. during fused tetanus d. during a single twitch |
c. during fused tetanus
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An elaborate network of membrane tubes in skeletal muscle cells that functions
in Ca2+ storage is the: a. sarcoplasmic reticulum b. mitochondria c. T-tubules d. Golgi apparatus |
a. sarcoplasmic reticulum
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In relaxed skeletal muscle the highest concentration of Ca2+ is found:
a. in synaptic vesicles b. within the sarcoplasmic reticulum c. bound to the troponin complex d. in the cytosol |
b. within the sarcoplasmic reticulum
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After hydrolyzing most of its ATP to supply the energy for muscle contraction,
the most rapid way of regenerating ATP in the muscle cell is: a. to transfer the phosphate of creatine phosphate to ADP b. anaerobic glycolysis of cellular stores of glycogen c. anaerobic glycolysis of glucose form the blood d. oxidation of fatty acids from the blood |
a. to transfer the phosphate of creatine phosphate to ADP
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Of the three muscle types (skeletal, cardiac, and smooth) which of the following
is a property of skeletal muscle only? a. cells are multinucleated b. has a striated appearance under a microscope c. has tropomyosin bound to the thin filaments d. Its contraction is triggered by an increase in the cytosolic Ca2+ concentration. |
a. cells are multinucleated
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Contraction of smooth muscle can be caused by all of the following except:
a. stimulation by the sympathetic nervous system b. stimulation by the parasympathetic nervous system c. stimulation by somatic motor neurons d. contraction can be spontaneous (due to pacemaker activity) |
c. stimulation by somatic motor neurons
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Which of the following best describes excitation-contraction coupling in skeletal
muscle? a. action potential travels down the t-tubule→influx of Ca2+ from the extracellular fluid→Ca2+-induced Ca2+ release from the sarcoplasmic reticulum→Ca2+ binds to the troponin complex b. action potential travels down the t-tubule→activates the DHP receptor→opening of the ryanodine receptor→Ca2+ release from the sarcoplasmic reticulum→Ca2+ binds to the troponin complex c. influx of Ca2+ into the cytoplasm→Ca2+ binds to calmodulin→activation of myosin light-chain kinase→phosphorylation of myosin d. action potential travels down the t-tubule→ influx of Ca2+ from the extracellular fluid→Ca2+ binds to the troponin complex |
b. action potential travels down the t-tubule→activates the DHP
receptor→opening of the ryanodine receptor→Ca2+ release from the sarcoplasmic reticulum→Ca2+ binds to the troponin complex |
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Which of the following is NOT a characteristic of cardiac muscle?
a. is found only in the heart b. is a glycolytic muscle, receiving most of its energy from anaerobic metabolism of glucose c. muscle cells are connected by gap junctions and desmosomes d. some cells have pacemaker activity |
b. is a glycolytic muscle, receiving most of its energy from anaerobic
metabolism of glucose |
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Most skeletal muscles contain:
a. muscle fibers all of the same type b. a mixture of fiber types c. a predominance of slow oxidative muscle fibers d. a predominance of fast glycolytic muscle fibers |
b. a mixture of fiber types
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Which of the following statements concerning all three muscle types (skeletal,
cardiac, and smooth) is FALSE? a. All muscle utilizes an increase in the cytosolic Ca2+ concentration to trigger contraction. b. All muscle contains both thick and thin filaments. c. All muscle has the contractile proteins arranged in sarcomeres. d. In all muscle, ATP is used to provide the energy to pump Ca2+ out of the cytosol during the relaxation phase of contraction. |
c. All muscle has the contractile proteins arranged in sarcomeres.
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The striations of a skeletal muscle observed under a microscope are created
by: a. the arrangement of the multiple nuclei in a muscle fiber b. the arrangement of thin and thick filaments c. the sarcoplasmic reticulum d. the T-tubules |
b. the arrangement of thin and thick filaments
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The thick filament of skeletal muscle contains:
a. actin b. myosin c. troponin d. tropomyosin |
b. myosin
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In an isotonic contraction, the skeletal muscle:
a. increases its tension but does not change in length b. changes in length as it generates a constant tension c. has no muscle tone d. always shortens in length |
b. changes in length as it generates a constant tension
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A motor unit is defined as:
a. a single motor neuron and all the skeletal muscle fibers that it innervates b. a single skeletal muscle fiber and all the motor neurons that innervate it c. all the skeletal muscles involved in movement of a single joint d. all the skeletal muscles which have their insertions on a single bone |
a. a single motor neuron and all the skeletal muscle fibers that it innervates
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Which of the following statements concerning the motor unit is false?
a. When the somatic motor neuron fires an action potential, all muscle fibers in the motor unit will contract. b. The largest motor units tend to be recruited first as muscle tension is increased. c. By gradually increasing the number of active motor units (recruitment of motor units), muscle tension can be gradually (and smoothly) increased. d. A motor neuron pool consists of many motor neurons, each of which innervates a motor unit within the same muscle. |
b. The largest motor units tend to be recruited first as muscle tension is
increased. |
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When compared to other skeletal muscle fibers, fast glycolytic fibers would
have: a. a larger diameter b. a greater capillary density (a richer supply of blood) c. a higher content of mitochondria d. a higher myoglobin content |
a. a larger diameter
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When compared to fast glycolytic muscle fibers, slow oxidative fibers would
have: a. fewer mitochondria b. a higher glycogen content c. a faster myosin ATPase activity d. a higher myoglobin content |
d. a higher myoglobin content
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A small diameter skeletal muscle fiber from a muscle important in maintaining
posture exhibits slow ATPase activity, and is virtually resistant to fatigue. It is red in appearance and possesses many mitochondria, but has low levels of stored glycogen. The muscle fiber type is: a. slow oxidative b. slow glycolytic c. fast glycolytic d. fast oxidative/glycolytic |
a. slow oxidative
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Smooth muscle is found in all of the following locations EXCEPT.
a. walls of blood vessels b. walls of the digestive tract c. wall of the urinary bladder d. the rotator cuff of the shoulder |
d. the rotator cuff of the shoulder
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Which of the following statements regarding single-unit smooth muscle is
false? a. Cells are coupled by numerous gap junctions. b. Cells contract together. c. Some cells are specialized to have pacemaker activity. d. Nervous stimulation is necessary to produce contraction. |
d. Nervous stimulation is necessary to produce contraction.
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In cardiac muscle…
a. the action potential is finished before contraction begins. b. there is an absolute refractory period during which the muscle cannot contract. c. the action potential and the contraction (i.e. force generated) overlap with one another. d. All of the above are correct. |
c. the action potential and the contraction (i.e. force generated) overlap with
one another. |
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During activities requiring aerobic endurance
a. most of the muscle's energy is produced in mitochondria b. fatigue occurs in a few minutes c. oxygen is not required d. glycolysis is the primary source of energy |
a. most of the muscle's energy is produced in mitochondria
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During anaerobic glycolysis
a. oxygen is not consumed b. ATP is produced c. pyruvic acid is produced d. All of the above are correct. |
d. All of the above are correct.
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The central nervous system (CNS):
a. refers to the brain only b. includes the brain and spinal cord only c. includes the brain, spinal cord and all sensory neurons d. refers only to the central structures of the forebrain (i.e. the diencephalon) |
b. includes the brain and spinal cord only
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The peripheral nervous system (PNS) includes:
a. interneurons only b. only those neurons that have their cell bodies outside of the CNS c. all neural structures outside the CNS d. the spinal nerves only |
c. all neural structures outside the CNS
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Neurons that convey impulses out of the CNS are referred to as:
a. sensory neurons b. interneurons c. afferent neurons d. efferent neurons |
d. efferent neurons
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A neuron conducting signals from a peripheral sensory receptor to the central
nervous system is referred to as a(n) ________________. a. motor neuron b. interneuron c. afferent neuron d. efferent neuron |
c. afferent neuron
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A ridge in the tissue forming the surface of the cerebral hemispheres is referred
to as a ___________. a. fissure b. gyrus c. sulcus d. prominence |
b. gyrus
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A shallow groove on the surface of the cerebral cortex is called a _________.
a. fissure b. gyrus c. sulcus d. furrow |
c. sulcus
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A nerve is a…
a. cable-like collection of many axons in the PNS b. grouping of nerve axons that interconnect regions of the CNS c. grouping of neuron cell bodies located outside the CNS d. grouping of neuron cell bodies within the CNS |
a. cable-like collection of many axons in the PNS
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In the nervous system, a nucleus is a…
a. cable-like collection of many axons in the PNS b. grouping of nerve axons that interconnect regions of the CNS c. grouping of neuron cell bodies located outside the CNS d. grouping of neuron cell bodies within the CNS |
d. grouping of neuron cell bodies within the CNS
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A tract is a…
a. cable-like collection of many axons in the PNS b. grouping of nerve axons that interconnect regions of the CNS c. grouping of neuron cell bodies located outside the CNS d. grouping of neuron cell bodies within the CNS |
b. grouping of nerve axons that interconnect regions of the CNS
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A ganglion is a…
a. cable-like collection of many axons in the PNS b. grouping of nerve axons that interconnect regions of the CNS c. grouping of neuron cell bodies located outside the CNS d. grouping of neuron cell bodies within the CNS |
c. grouping of neuron cell bodies located outside the CNS
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The diencephalon includes the _________________.
a. cerebrum b. midbrain, pons, and medulla oblongata c. cerebellum d. epithalamus, thalamus, and hypothalamus |
d. epithalamus, thalamus, and hypothalamus
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The brainstem consists of the:
a. diencephalon, pons, midbrain, and medulla b. pons, midbrain, and medulla c. cerebrum, pons, midbrain, and medulla d. cerebellum, pons, midbrain, and medulla |
b. pons, midbrain, and medulla
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Which of the following contains a spiderweb-like network of fibers through
which cerebrospinal fluid flows? a. subarachnoid space b. subdural space c. dural sinus d. pia mater |
a. subarachnoid space
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What layer of the protective covering of the brain is very delicate and adheres
tightly to the surface of the brain and spinal cord? a. arachnoid b. choroid plexus c. pia mater d. dura mater |
c. pia mater
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Cerebrospinal fluid…
a. has the same composition as blood plasma b. is secreted into the brain ventricles by the arachnoid villi c. is formed in the choroid plexuses of the ventricles d. fills the ventricles, subarachnoid space, and dural sinuses |
c. is formed in the choroid plexuses of the ventricles
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Which of the following is a property of the blood-brain barrier?
a. Astrocyte foot processes surround the CNS capillaries. b. It is absent in portions of the hypothalamus. c. It is generally permeable to O2 and CO2. d. All of the above. |
d. All of the above.
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Cerebrospinal fluid (CSF) enters the subarachnoid space through the
a. cerebral aqueduct b. lateral and median apertures c. interventricular foramen d. superior sagittal sinus |
b. lateral and median apertures
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Absorption from arachnoid granulations returns CSF to the
a. third ventricle b. fourth ventricle c. arterial circulation d. venous circulation |
d. venous circulation
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Which of the following is not a function of cerebrospinal fluid?
a. provides an optimal chemical environment for neurons b. provides buoyant support for the brain c. acts as a transport medium for nutrients and waste products d. provides ATP for nerve impulses |
d. provides ATP for nerve impulses
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White matter within the central nervous system:
a. forms the cerebral cortex b. consists largely of myelinated fibers bundled into “tracts” c. contains no neuroglia d. contains neuron cell bodies and dendrites |
b. consists largely of myelinated fibers bundled into “tracts”
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The cerebral cortex contains:
a. myelinated axons b. oligodendrocytes c. neuron cell bodies and dendrites d. fiber tracts |
c. neuron cell bodies and dendrites
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The cerebral hemispheres communicate with each other via several bundles of
axons. These bundles of axons are referred to as ________________. a. association tracts b. projection tracts c. commissural tracts d. pyramidal tracts |
c. commissural tracts
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The largest of the bundles of axons connecting the two cerebral hemispheres is
the _____________. a. anterior commisure b. posterior commisure c. pyrimidal tract d. corpus callosum |
d. corpus callosum
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The function of association tracts is to connect:
a. adjacent areas of gray matter within a cerebral hemisphere b. corresponding areas of the two cerebral hemispheres c. areas of the cerebral cortex with lower brain centers d. the basal nuclei to the cerebellum |
a. adjacent areas of gray matter within a cerebral hemisphere
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Which of the following would be consistent with a blow to the head resulting in
paralysis of muscles in the right arm? a. damage to the left precentral gyrus b. damage to the right precentral gyrus c. damage to the left postcentral gyrus d. damage to the right postcentral gyrus |
a. damage to the left precentral gyrus
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