anatomy studying
Which of the following is NOT true of an electrical synapse? Transmission across these synapses is very rapid. Communication through these synapses may be unidirectional or bidirectional. They are specialized for release and reception of chemical neurotransmitters. They are less common than chemical synapses.
They are specialized for release and reception of chemical neurotransmitters
Large-diameter nerve fibers conduct impulses much faster than small-diameter fibers. True False
True
Myelination of the nerve fibers in the central nervous system is the job of the oligodendrocyte. True False
True
The overlapping functions of the nervous system are sensory input, integration, and motor output. True False
True
A triad is composed of a T-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum. How are these components connected? Potassium leak channels. Voltage-gated sodium channels. Myosin cross-bridge binding sites. A series of proteins that control calcium release.
a series of proteins that control calcium release
The term aponeurosis refers to ________. a sheetlike indirect attachment to a skeletal element the rough endoplasmic reticulum the bands of myofibrils the tropomyosin-troponin complex
a sheetlike indirect attachment to a skeletal element
In a neuromuscular junction, synaptic vesicles in the motor neuron contain which neurotransmitter? acetylcholine (ACh) serotonin norepinephrine dopamine
acetylcholine
Synaptic vesicles at the neuromuscular junction contain __________. calcium ACh receptors acetylcholine synaptic potentials
acetylcholine
How is acetylcholine (ACh) removed from the synaptic cleft? acetylcholinesterase (AChE; an enzyme) diffusion away from the synaptic cleft a reuptake pump on the axon terminal
acetylcholinesterase (AChE; an enzyme)
After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction? the action potential stops going down the overloaded T tubules calcium ions returning to the terminal cisternae acetylcholinesterase destroying the ACh the tropomyosin blocking the myosin once full contraction is achieved
acetylcholinesterase destroying the ACh
A myosin head binds to which molecule to form a cross bridge? troponin actin tropomyosin
actin
Which of the following is not a connective tissue sheath that wraps individual muscle fibers? epimysium aponeurosis endomysium perimysium
aponeurosis
Which of the following statements about smooth muscle is true
fibers are small and spindle shaped
What would happen if acetylcholine was not removed from the synaptic cleft? The acetylcholine receptors would not open. Multiple action potentials would occur in the motor neuron. Voltage-gated Ca2+ channels would remain open. Multiple action potentials would occur in the muscle fiber.
Multiple action potentials would occur in the muscle fiber.
Which of the following statements is most accurate? Muscle tension remains relatively constant during isotonic contraction. The I band lengthens during isotonic contraction. T tubules may be sliding during isotonic contraction. Myofilaments slide during isometric contractions.
Muscle tension remains relatively constant during isotonic contraction
Which of the following is NOT a difference between graded potentials and action potentials? Graded potentials occur along dendrites, whereas action potentials occur along axons. Spatial summation is used to increase the amplitude of a graded potential; temporal summation is used to increase the amplitude of an action potential. Graded potentials can result from the opening of chemically gated channels; action potentials require the opening of voltage-gated channels. Greater stimulus intensity results in larger graded potentials, but not larger action potentials.
spatial summation is used to increase the amplitude of a graded potential; temporal summation is used to increase the amplitude of an action potential
During depolarization, the inside of the neuron's membrane becomes less negative. True False
True
The part of a neuron that conducts impulses away from its cell body is called a(n) ________. dendrite axon Schwann cell neurolemma
axon
anaerobic pathway
25 meter swim
Which event causes cross bridge detachment? nervous input ends release of ADP and inorganic phosphate from the myosin head ATP binding to the myosin head release of calcium from troponin
ATP binding to the myosin head
After a power stroke, the myosin head must detach from actin before another power stroke can occur. What causes cross bridge detachment? Calcium ions bind to troponin. Acetylcholine binds to receptors in the junctional folds of the sarcolemma. ATP binds to the myosin head. ADP and inorganic phosphate are bound to the myosin head.
ATP binds to the myosin head
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? Acetylcholine binds to its receptor in the junctional folds of the sarcolemma. Its receptor is linked to a G protein. When the action potential reaches the end of the axon terminal, voltage-gated sodium channels open and sodium ions diffuse into the terminal. Acetylcholine is released and moves across the synaptic cleft bound to a transport protein. Acetylcholine is released by axon terminals of the motor neuron.
Acetlycholine is released by axon terminals of the motor neuron
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? Acetylcholine is transported into the postsynaptic neuron by receptor-mediated endocytosis. Acetylcholine diffuses away from the cleft. Acetylcholine is transported back into the axon terminal by a reuptake mechanism. Acetylcholine is degraded by acetylcholinesterase.
Acetylcholine is degraded by acetlychoinesterase
How/when does the myosin head cock back to store energy for the next cycle? The power stroke cocks the myosin head. when ADP is released from the myosin head After the myosin head detaches, energy from ATP hydrolysis is used to re-cock the myosin head. The sliding of the actin myofilament during the power stroke re-cocks myosin heads that have previously delivered their power stroke.
After the myosin head detaches, energy from ATP hydrolysis is used to re-cock the myosin head.
What is the ion released from the terminal cisternae that combines with troponin and removes the blocking action of tropomyosin, resulting in the formation of cross bridges?
Ca2+ Ca2+ combines with troponin, changes shape and removes the blocking action of tropomyosin, allowing cross bridges to form
Excitation-contraction coupling directly requires which of the following substances? ATP and glucose Ca2+ only ATP only Ca2+ and ATP
Ca2+ and ATP
Which of the following does NOT occur during skeletal muscle contraction?
Calcium binds to mysoin heads. Increase of hemoglobin concentration in muscle fibers is not a process that occurs during muscle contraction.
What is the role of calcium in the cross bridge cycle? Calcium binds to active sites on actin, forming the cross bridge. Calcium binds to myosin, causing the myosin head to release from the actin myofilament. Calcium binds to troponin, altering its shape. Calcium binds to troponin, exposing the active site on troponin.
Calcium binds to troponin, altering its shape.
What specific event triggers the uncovering of the myosin binding site on actin? Calcium ions bind to tropomyosin and change its shape. Calcium ions bind to troponin and change its shape. Sodium ions bind to troponin and change its shape. Calcium release channels open in the sarcoplasmic reticulum, and calcium levels rise in the sarcoplasm.
Calcium ions bind to troponin and change its shape
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? Excitation refers to the shape change that occurs in voltage-sensitive proteins in the sarcolemma. Excitation refers to the propagation of action potentials along the axon of a motor neuron. Excitation refers to the release of calcium ions from the sarcoplasmic reticulum. Excitation, in this case, refers to the propagation of action potentials along the sarcolemma.
Excitation refers to the propagation of action potentials along the sarcolemma
Strong stimuli cause the amplitude of action potentials generated to increase. True False
False
The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place. True False
False
The autonomic nervous system is under voluntary control; whereas, the somatic nervous system is involuntary. True False
False
Which of the following substances increases in quantity during repetitive muscle contraction during oxygen deficit?
Lactic acid
BMD (2,3-butanedione 2-monoximime) inhibits myosin, such that ATP can bind to myosin but myosin is unable to hydrolyze the bound ATP. What effect would BMD have on the cross bridge cycle? Myosin heads would remain attached to actin, unable to detach. Tropomyosin would not move, and the active sites on actin would not be exposed. Myosin heads would remain detached, unable to cock. Myosin heads would remain attached to actin, unable to perform the power stroke.
Myosin heads would remain detached, unable to cock.
Which of the following statements is true? Cardiac muscle cells are found in the heart and large blood vessels. Cardiac muscle cells have many nuclei. Smooth muscle cells have T tubules. Skeletal muscle cells are long and cylindrical with many nuclei.
Skeletal muscle cells are long and cylindrical with many nuclei.
Which of the following statements is INCORRECT?
Skeletal muscles are responsible for the pumping action of the heart
Calcium entry into the axon terminal triggers which of the following events? Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine. Cation channels open and sodium ions enter the axon terminal while potassium ions exit the axon terminal. Acetylcholine binds to its receptor. Acetylcholine is released into the cleft by active transporters in the plasma membrane of the axon terminal.
Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetlycholine
Which of the following characteristics is unique to smooth muscle?
The absence of striations
he 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? The contraction of the muscles in these activities helps maintain the shape, size, and strength of muscles, as well as joint mobility. The contraction of the muscles in these activities reverses myotonic dystrophy and rebuilds muscle mass. The contraction of the muscles in these activities reverses sarcopenia and rebuilds muscle mass. It does not. Only weight-bearing exercises maintain the shape, size and strength of muscles.
The contraction of the muscles in these activities helps maintain the shape, size, and strength of muscles, as well as joint mobility.
What role does tropomyosin play in the cross bridge cycle? Tropomyosin binds to calcium, causing muscle relaxation. Tropomyosin moves the actin filament relative to the myosin filament. The displacement of tropomyosin exposes the active sites of actin, allowing cross bridges to form. Tropomyosin pushes the myosin head away, causing cross bridge detachment.
The displacement of tropomyosin exposes the active sites of actin, allowing cross bridges to form.
During contraction, what prevents actin myofilaments from sliding backward when a myosin head releases? The actin myofilament can only move in one direction relative to the myosin filament. There are always some myosin heads attached to the actin myofilament when other myosin heads are detaching. The cross bridge remains in place, preventing the actin myofilament from sliding. Calcium blocks the active sites on actin.
There are always some myosin heads attached to the actin myofilament when other myosin heads are detaching.
What is the role of tropomyosin in skeletal muscles? Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules. Tropomyosin is the chemical that activates the myosin heads. Tropomyosin is the receptor for the motor neuron neurotransmitter. Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.
Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
How does troponin facilitate cross bridge formation? Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin. Troponin moves away from the active sites on actin, permitting cross bridge formation. Troponin gathers excess calcium that might otherwise block actin's progress. Troponin hydrolyzes ATP, which provides the energy necessary for cross bridges to form.
Troponin controls the position of tropomyosin on the thin filament, enabling myosin heads to bind to the active sites on actin.
Axon diameter and degree of myelination determine nerve impulse conduction velocity. True False
True
What is the functional unit of a skeletal muscle called? a sarcomere the sarcoplasmic reticulum a myofilament a myofibril
a sarcomere
Most skeletal muscles contain ________. a predominance of slow oxidative fibers a mixture of fiber types a predominance of fast oxidative fibers muscle fibers of the same type
a mixture of fiber types
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? a sprint by an Olympic runner gym climbing playing baseball or basketball a long, relaxing swim
a long, relaxing swim
Muscle tone is ________. the condition of athletes after intensive training the feeling of well-being following exercise the ability of a muscle to efficiently cause skeletal movements a state of sustained partial contraction
a state of sustained partial contraction
The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________. resting period absolute refractory period repolarization depolarization
absolute refractory period
The sliding filament model of contraction involves ________. actin and myosin lengthening in order to slide past each other the shortening of thick filaments so that thin filaments slide past the Z discs sliding over the myofilaments actin and myosin sliding past each other and partially overlapping
actin and myosin sliding past each other and partially overlapping
The sequence of electrical changes that occurs along the sarcolemma when a muscle fiber is known as the ______
action potential
Which of the following is not a role of ionic calcium in muscle contraction? activates epinephrine released from adrenal gland removes contraction inhibitor triggers neurotransmitter secretion binds with troponin
activates epinephrine released from adrenal gland
Where does 95% of the energy needed for contraction come from during moderated exercise?
aerobic respiration
Which of the following correctly describes a graded potential? voltage stimulus to initiate voltage regulated repolarization long distance signaling amplitude of various sizes
amplitude of various sizes
Which of the following describes the nervous system integrative function? *analyzes sensory information, stores information, makes decisions *senses changes in the environment *responds to stimuli by gland secretion or muscle contraction
analyzes sensory information, stores information, makes decisions
What causes the release of calcium from the terminal cisternae of the sarcoplasmic reticulum within a muscle cell? arrival of an action potential ATP troponin calcium ion pump
arrival of an action potential
What is the role of calcium ions in muscle contraction? increase levels of myoglobin form hydroxyapatite crystals bind to regulatory sites on troponin to remove contraction inhibition reestablish glycogen stores
bind to regulatory sites on troponin to remove contraction inhibition
What causes the myosin head to disconnect from actin? binding of ATP binding of calcium binding of troponin hydrolysis of ATP
binding of ATP
The binding of the neurotransmitter to receptors on the motor end plate causes which of the following to occur? Binding causes chemically gated potassium channels to open in the motor end plate. Binding causes potassium voltage-gated channels to open in the motor endplate. Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate. Binding causes voltage-gated sodium channels to open in the motor endplate.
binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate
The term central nervous system refers to the ________. brain, spinal cord, and peripheral nerves peripheral and spinal nerves spinal cord and spinal nerves brain and spinal cord
brain and spinal cord
What is the primary mechanism by which ACh is cleared from the synaptic cleft? broken down by acetylcholinesterase reuptake into the synaptic terminal endocytosis by synaptic vesicles diffusion away from the synaptic cleft
broken down by acetylcholinesterase
What most directly causes synaptic vesicles to release acetylcholine into the synaptic cleft? calcium entering the axon terminal depolarization of the sarcolemma sodium entering the muscle fiber an action potential arriving at the axon terminal
calcium entering the axon terminal
What is the cause of rigor mortis?
calcium influx into the sarcoplasm after death
Which of the following is most directly responsible for the coupling of excitation to contraction of skeletal muscle fibers? Sodium ions. Calcium ions. Acetylcholine. Action potentials.
calcium ions
Calcium ions couple excitation of a skeletal muscle fiber to contraction of the fiber. Where are calcium ions stored within the fiber? Calcium ions are stored in the mitochondria. Calcium ions are stored in the transverse tubules. Calcium ions are stored in the sarcoplasmic reticulum. Calcium ions are stored in the nuclei.
calcium ions are stored in the sarcoplasmic reticulum
Excitation of the sarcolemma is coupled or linked to the contraction of a skeletal muscle fiber. What specific event initiates the contraction? Sodium release from the sarcoplasmic reticulum initiates the contraction. Action potentials propagate into the interior of the skeletal muscle fiber. Voltage-sensitive proteins change shape. Calcium release from the sarcoplasmic reticulum initiates the contraction.
calcium release from the sarcplasmic reticulum initiates the contraction
Which of the following binds calcium ions in a smooth muscle, causing contraction?
calmodulin
What part of the nervous system performs information processing and integration? central nervous system somatic nervous system sympathetic nervous system parasympathetic nervous system
central nervous system
In an isotonic contraction, the muscle ________. changes in length and moves the "load" rapidly resynthesizes creatine phosphate and ATP does not change in length but increases tension never converts pyruvate to lactate
changes in length and moves the "load"
Acetylcholine receptors are best characterized as what type of channel? voltage-gated Na+-K+ channels chemically gated Na+-K+ channels voltage-gated Ca2+ channels chemically gated Ca2+ channels
chemically gated Na+-K+ channels
All of the following terms refer to the ability to receive and respond to a stimulus EXCEPT _______
contractibility
When does cross bridge cycling end? Cross bridge cycling ends when ATP binds to the myosin head. Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin. Cross bridge cycling ends when calcium ions are passively transported back into the sarcoplasmic reticulum. Cross bridge cycling ends when calcium release channels in the sarcoplasmic reticulum open.
cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin
here in the cross bridge cycle does ATP hydrolysis occur? during the removal of calcium from troponin during the power stroke during the movement of tropomyosin to expose the active sites on actin during the cocking of the myosin head
during the cocking of the myosin head
Which of the following allows recoil of muscle fibers when contraction ends
elastic filaments
Which of the following surrounds the individual muscle cell? perimysium fascicle endomysium epimysium
endomysium
What is the functional role of the T tubules? hold cross bridges in place in a resting muscle synthesize ATP to provide energy for muscle contraction enhance cellular communication during muscle contraction stabilize the G and F actin
enhance cellular communication during muscle contraction
The dense layer of collagen fibers that surround an entire skeletal muscle is the ________
epimysium
An entire skeletal muscle is surrounded by _____
epimysium perimysium surrounds bundles of fibers, and enodmysium surrounds each fiber. The entire muscle is surrounded by epimysium
What means of membrane transport is used to release the neurotransmitter into the synaptic cleft? exocytosis a protein carrier a channel
exocytosis
Action potentials travel the length of the axons of motor neurons to the axon terminals. These motor neurons __________. arise in the epimysium of a skeletal muscle and extend to individual skeletal muscle fibers extend from the brain to the sarcolemma of a skeletal muscle fiber extend from the spinal cord to the sarcolemma of a skeletal muscle fiber extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber
extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber
Skeletal muscle cells are grouped into bundles called __________. myofilaments fascicles myofibrils muscle fibers
fascicles
Bipolar neurons are commonly ________. called neuroglial cells found in ganglia found in the retina of the eye motor neurons
found in the retina of the eye
Collections of nerve cell bodies in the peripheral nervous system are called ________. ganglia nuclei nerves tracts
ganglia
"Cross bridges" that link between the thick and thin filaments are formed by the ________
globular head of thick filaments
An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is ________. the electron transport chain the citric acid cycle glycolysis hydrolysis
glycolysis
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. contraction relaxation refractory latent
latent
The type of muscle contraction in which the muscle fibers produce increased tension, but the muscle neither shortens nor lengthens, is called ______
isometric
Which of the following is not a characteristic of skeletal muscle contraction?
it contracts rapidly
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 ________. hydrochloric acid lactic acid stearic acid a strong base
lactic acid
Which of the following is a factor that affects the velocity and duration of muscle contraction? size of the muscle fibers stimulated number of muscle fibers stimulated load on the fiber muscle length
load on the fiber
aerobic pathway
marathons
Which of the following types of glial cells monitors the health of neurons, and can transform into a special type of macrophage to protect endangered neurons? microglia astrocytes oligodendrocytes ependymal cells
microglia
Which of the following types of neurons carry impulses away from the central nervous system (CNS)? motor association afferent sensory
motor
What part of the sarcolemma contains acetylcholine receptors? end of the muscle fiber part adjacent to another muscle cell any part of the sarcolemma motor end plate
motor end plate
Which of the following is the correct sequence of events for muscle contractions? neurotransmitter release, muscle cell action potential, motor neuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments
motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments
A motor neuron and all the muscle fibers it supplies is called an _______
motor unit a motor unit is a nerve muscle functional unit, with a motor neuron supplying all the muscle fibers
Which of the following would be recruited later in muscle stimulation when contractile strength increases? motor units with larger, less excitable neurons motor units with the longest muscle fibers large motor units with small, highly excitable neurons many small motor units with the ability to stimulate other motor units
motor units with larger, less excitable neurons
A sarcomere is a part of a ________
myofibril
The contractile units of skeletal muscles are ________. T tubules myofibrils mitochondria microtubules
myofibrils
In the sliding filament model of muscle contraction, the myofilaments side over eachother, resulting in the overlapping of actin and ___________
myosin
What, specifically, is a cross bridge? myosin binding to actin calcium binding to troponin ATP binding to the myosin head tropomyosin covering the active sites on actin
myosin binding to actin
The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. What is a cross bridge? A myosin head bound to actin Troponin bound to tropomyosin Calcium bound to troponin ATP bound to a myosin head
myosin head bound to actin
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________. positively charged and contains more sodium negatively charged and contains less sodium positively charged and contains less sodium negatively charged and contains more sodium
negatively charged and contains less sodium
Each skeletal muscle fiber is controlled by a neuron at a single __________
neuromuscular junction
Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, ________. cross bridge attachment would be optimum because of all the free binding sites on actin ATP consumption would increase because the sarcomere is "trying" to contract no muscle tension could be generated maximum force production would result because the muscle has a maximum range of travel
no muscle tension could be generated
Which of the following are gaps found along a myelin sheath? outer collar of perinuclear cytoplasm axolemma terminal boutons nodes of Ranvier
nodes of raniver
Duchenne muscular dystrophy could theoretically be cured if a technique was developed that would _________. strengthen the dystrophin proteins that are present in the patient's muscle fibers double the existing number of dystrophin molecules in the patient's muscle fibers strengthen the thick and thin filaments in the patient's muscle fibers none of the above
none
Schwann cells are functionally similar to ________. oligodendrocytes astrocytes ependymal cells microglia
oligodendrocytes
The altering contraction and relaxation of opposing layers of smooth muscle is referred to as __________
peristalisis
Which of the following is NOT a type of circuit? reverberating circuits converging circuits pre-discharge circuits diverging circuits
pre-discharge circuits
What is the primary function of wave summation? prevent muscle fatigue produce smooth, continuous muscle contraction prevent muscle relaxation increase muscle tension
produce smooth, continuous muscle contraction
Which of the following is not a function of astrocytes? support and brace neurons anchor neurons to blood vessels guide the migration of young neurons, synapse formation, and helping to determine capillary permeability control the chemical environment around neurons provide the defense for the CNS
provide the defense for the CNS
Elasticity refers to the ability of a muscle fiber to ___________
recoil and resume its resting length after being stretched
When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods? latent period relaxation period fatigue period refractory period
refractory period
The major function of the sarcoplasmic reticulum in muscle contraction is to ________. synthesize actin and myosin myofilaments make and store phosphocreatine regulate intracellular calcium concentration provide a source of myosin for the contraction process
regulate intracellular calcium concentration
What causes the power stroke? hydrolysis of ATP release of ADP and Pi calcium binding of ATP
release of ADP and Pi
The refractory period in which the muscles will NOT contract if stimulated occurs during ______ of the muscle cell.
repolarization
ACh receptors are found mainly in the __________. terminal cisternae synaptic vesicles axon terminal sarcolemma
sarcolemma
he muscle cell membrane is called the ________. perimysium sarcolemma epimysium endomysium
sarcolemma
The functional unit of contraction in a skeletal muscle is the ____________-
sarcomere
What structure in skeletal muscle cells functions in calcium storage? sarcoplasmic reticulum mitochondria myofibrillar network intermediate filament network
sarcoplasmic reticulum
Muscle tissue has all of the following properties except ________. extensibility contractility secretion excitability
secretion
When the chemically gated ion channels open, which ion is mainly responsible for depolarizing the sarcolemma? sodium calcium potassium ACh
sodium
yoglobin ________. stores oxygen in muscle cells is a protein involved in the direct phosphorylation of ADP produces the end plate potential breaks down glycogen
stores oxygen in muscle cells
Creatine phosphate functions in the muscle cell by ________. forming a temporary chemical compound with myosin storing energy that will be transferred to ADP to resynthesize ATP inducing a conformational change in the myofilaments forming a chemical compound with actin
storing energy that will be transferred to ADP to resynthesize ATP
The space between the neuron and the muscle is the _________
synaptic cleft
What is name given to the regularly spaced infoldings of the sarcolemma? sarcoplasmic reticulum terminal cisternae transverse or T tubules motor endplates
t tubules
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? cytosol terminal cisternae of the sarcoplasmic reticulum sarcolemma T tubule
terminal cisternae of the sarcoplasmic reticulum
Which of the following best describes the composition of the structure known as a triad in a skeletal muscle fiber?
terminal cisternae, transverse tubule and terminal cistern
What is the most distinguishing characteristic of muscle tissue? the ability to transform chemical energy into mechanical energy the ability to respond to nervous stimulation the diversity of activity of muscle tissue the design of the fibers
the ability to transform chemical energy into mechanical energy
What produces the striations of a skeletal muscle cell? the T tubules the arrangement of myofilaments the sarcoplasmic reticulum a difference in the thickness of the sarcolemma
the arrangement of myofilaments
What does excess postexercise oxygen consumption represent? the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used the amount of oxygen taken into the body immediately after the exertion the amount of oxygen equal to the oxygen already used amount of oxygen needed for aerobic activity to accomplish the same amount of work
the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
How does the myosin head obtain the energy required for activation? The energy comes from the hydrolysis of ATP. The energy comes from the hydrolysis of GTP. The energy comes from oxidative phophorylation. The energy comes from the direct phosphorylation of ADP by creatine phosphate.
the energy comes from the hydrolysis of ATP
Sodium and potassium ions do not diffuse in equal numbers through ligand-gated cation channels. Why? The inside surface of the sarcolemma is negatively charged compared to the outside surface. Sodium ions diffuse inward along favorable chemical and electrical gradients. The inside surface of the sarcolemma is negatively charged compared to the outside surface. Potassium ions diffuse inward along favorable chemical and electrical gradients. The outside surface of the sarcolemma is negatively charged compared to the inside surface. Sodium ions diffuse outward along favorable chemical and electrical gradients. The outside surface of the sarcolemma is negatively charged compared to the inside surface. Potassium ions diffuse outward along favorable chemical and electrical gradients.
the inside surface of the sarcolemma is negatively charged compared to the outside surface. Sodium ions diffuse inward along favorable chemical and electrical gradients
A second nerve impulse cannot be generated until ________. all sodium gates are closed the membrane potential has been reestablished the Na ions have been pumped back into the cell proteins have been resynthesized
the membrane potential has been reestablished
Which of the following muscles is voluntary?
the muscle that extends the arm at the elbow
Acetylcholine binds to its receptor in the sarcolemma and triggers __________. the opening of calcium-release channels the opening of voltage-gated calcium channels the opening of ligand-gated cation channels the opening of ligand-gated anion channels
the opening of ligand-gated cation channels
What structure is the functional unit of contraction in a skeletal muscle fiber? The sarcomere The junctional folds of the sarcolemma The cross bridge The triad
the sarcomere
Which of the following allows us to consciously control our skeletal muscles? the parasympathetic division of the autonomic nervous system the afferent division of the nervous system the somatic nervous system the sympathetic division of the autonomic nervous system
the somatic nervous system
If bacteria invaded the CNS tissue, microglia would migrate to the area to engulf and destroy them. True False
true
Which of the following is not characteristic of neurons? They are mitotic. They conduct impulses. They have extreme longevity. They have an exceptionally high metabolic rate.
they are mitotic
The term that means a continued mild or partial contraction of a muscle that keeps it healthy and ready to respond is muscle _________
tone
The binding of calcium to which molecule causes the myosin binding sites to be exposed? actin tropomyosin myosin troponin
troponin
Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments. True False
true
Cells of unitary smooth muscle are found in the longitudinal and circular muscle layers of the intestine. True False
true
Peristalsis is characteristic of smooth muscle. True False
true
What is the relationship between the number of motor neurons recruited and the number of skeletal muscle fibers innervated? A motor neuron typically innervates only one skeletal muscle fiber. Typically, hundreds of skeletal muscle fibers are innervated by a single motor neuron. A skeletal muscle fiber is innervated by multiple motor neurons. Motor neurons always innervate thousands of skeletal muscle fibers.
typically hundreds of skeletal muscle fibers are innervated by a single motor neuron
When an action potential arrives at the axon terminal of a motor neuron, which ion channels open? voltage-gated calcium channels voltage-gated sodium channels chemically gated calcium channels voltage-gated potassium channels
voltage gated calcium channels
direct phosphorylation
weight lifting
