A&P Test 5
How many somatic motor neurons stimulate one muscle fiber? 0 1 2 3 4
1
Aerobic respiration produces approximately _________ more ATPs per glucose molecule than glycolysis does. 12 24 36 48 100
36
During muscle contraction, a single myosin head consumes ATP at a rate of about __________ ATP per second. 1 3 5 7 9
5
Which of the following individuals would have more mitochondria in her skeletal muscle? A 50-year-old sedentary computer programmer A 22-year-old soccer player A long-term hospice patient A model on a reduced-calorie diet A newborn
A 22-year-old soccer player
Which of the following is true regarding unmyelinated nerve fibers in the PNS? A Schwann cell folds its plasma membrane around several fibers . A Schwann cells wraps its plasma membrane around each individual fiber as it does with myelinated fibers. An oligodendrocyte cells wraps its plasma membrane around each fiber as it does with myelinated fibers. Satellite cells cluster around each axon to form a pseudo-myelin sheath.
A Schwann cell folds its plasma membrane around several fibers .
Conduction of a nerve impulse would be the fastest in which of the following? A large diameter myelinated fiber A small diameter myelinated fiber A large unmyelinated fiber A small unmyelinated fiber A small fiber with multiple Schwann cells
A large diameter myelinated fiber
A neuron receives a stimulus. Which of the following events happens next? A local potential develops Threshold is reached Hyperpolarization of the membrane Repolarization of the membrane A resting membrane potential is established
A local potential develops
What type of neural circuit is best for producing a prolonged output? A converging circuit A diverging circuit A reverberating circuit A presynaptic pool An autonomic pool
A reverberating circuit
Which of these is an example of an EPSP in a typical neuron? A voltage change from 0 mV to +0.35 mV A voltage change from -70 mV to -69.5 mV A voltage change from -69.5 mV to -70 mV A voltage change from +35 mV to 0 mV A voltage change from -70 mV to -70.5 mV
A voltage change from -70 mV to -69.5 mV
Which neurotransmitter excites skeletal muscle and inhibits cardiac muscle? Norepinephrine Dopamine Histamine Acetylcholine β-endorphin
Acetylcholine
How does a neuron transport enzymes produced in the neurosoma to its axon terminals? Along microtubules By diffusion Via cytoplasmic streaming Through co-transport
Along microtubules
Which of the following will cause the plasma membrane to hyperpolarize when at its RMP? An inflow of sodium An inflow of potassium An inflow of calcium An inflow of chloride An outflow of chloride
An inflow of chloride
Where is dystrophin, the protein that is defective in muscular dystrophy, normally found? Between the outermost myofilaments and the sarcolemma of a muscle fiber As a transmembrane protein of the sarcolemma In the Z discs of skeletal and cardiac muscle In the dense bodies of smooth muscle Bridging the gap between the sarcolemma and axon terminal
Between the outermost myofilaments and the sarcolemma of a muscle fiber
Which of the following has the largest mitochondria? Slow oxidative fibers Fast glycolytic fibers Cardiac muscle Smooth muscle Intermediate fibers
Cardiac muscle
The respiratory center gathers information from a variety of sources in order to set the rate and depth of breathing. This is an example of what type of neural circuit? Convergent Divergent Reverberating Parallel after-discharge
Convergent
Place the following events in synaptic transmission at a cholinergic synapse in order: A - A postsynaptic potential is produced; B - Voltage gated calcium channels open and calcium enters the cell; C - ACh is released and diffuses across the synaptic cleft; D - A nerve signal arrives at an axon terminal; E - Ligand gated sodium channels open and sodium enters the cell. D, B, C, E, A D, B, E, A, C B, C, D, E, A B, D, C, A, E
D, B, C, E, A
In which part of a neuron is the postsynaptic membrane usually found? Axon terminal Axon Dendrite Perikaryon Axon collateral
Dendrite
What would be the best explanation for why myelinated fibers conduct signals faster than unmyelinated fibers? There are no internodes in unmyelinated fibers. There are more internodes in unmyelinated fibers. Facilitated diffusion of sodium and potassium is faster in myelinated fibers. Active transport of sodium and potassium is faster in myelinated fibers. Diffusion of ions along the axoplasm is faster.
Diffusion of ions along the axoplasm is faster.
Parkinson disease is a progressive loss of motor function due to the degeneration of specific neurons. These neurons secrete an inhibitory neurotransmitter that prevents excessive activity in motor centers of the brain. What neurotransmitter is this? Serotonin Dopamine Acetylcholine GABA GlutamateDopamine
Dopamine
Place the following events of synaptic transmission at an adrenergic synapse in order: A - ATP is converted to cAMP B - The cell's metabolism is altered C - G protein binds adenylate cylase D - The G protein dissociates E - NE binds the receptor E, D, C, A, B E, D, A, C, B D, E, C, A, B D, E, A, C, B
E, D, C, A, B
Which of the following is a property of collagen? Contractility Excitability Elasticity Expendability Impermeability
Elasticity
What property of neurons allows them to respond to changes in the environment? Excitability Conductivity Secretion Permeability
Excitability
What is the opposite of presynaptic inhibition? Coding Integration Recruitment Summation Facilitation
Facilitation
Where does saltatory conduction occur? From node to node in myelinated fibers From node to node in unmyelinated fibers Down the entire length of a myelinated fiber Down the entire length of an unmyelinated fiber
From node to node in myelinated fibers
Which of these happens first in an adrenergic synaptic transmission? ATP is converted to cyclic AMP Adenylate cyclase is activated G protein dissociates from the NE receptor G protein binds to adenylate cyclase Cyclic AMP induces several effects in the cell
G protein dissociates from the NE receptor
Which of the following would be caused by a contraction of smooth muscle? Goose bumps Blood leaving the left ventricle of the heart Elevating the eyebrows Blinking the eyelids Deep inspiration
Goose bumps
Inhibitory postsynaptic potentials (IPSPs) are associated with which of the following? Depolarization of the cell membrane Repolarization of the cell membrane Hyperpolarization of the cell membrane No change in the cell membrane potential No change of the threshold
Hyperpolarization of the cell membrane
In an action potential, which event directly follows repolarization? Threshold is reached Hyperpolarization of the membrane Depolarization of the membrane Hypopolarization of the membrane The resting membrane potential is reinstated
Hyperpolarization of the membrane
An inhibitory local potential causes which of the following? Depolarization of the plasma membrane Hyperpolarization of the plasma membrane Repolarization of the plasma membrane Neutralization of the plasma membrane Drifting of the membrane potential towards the resting membrane potential
Hyperpolarization of the plasma membrane
Where are unmyelinated nerve fibers surrounded by Schwann cells? In the PNS In the CNS In the PNS and CNS Nowhere. Unmyelinated nerve fibers are never surrounded by Schwann cells. References Multiple Choice Section: 12.03 Which of the following is true regarding unmyelinated nerve fibers in the PNS? A Schwann
In the PNS
Some antidepressant drugs act by inhibiting monoamine oxidase (MAO). What is the function of this enzyme? It binds to chloride gates. It breaks down monoamines. It blocks sodium channels. It converts ATP to cyclic AMP. It degrades acetylcholine.
It breaks down monoamines.
In PNS nerve fiber regeneration, how is a growing axon directed to its original destination? It grows within a regeneration tube. The axonal terminals grow towards the neurosoma until the two severed fragments are reunited. The axon grows a collateral that is directed by growth factors secreted by the postsynaptic neuron. Injured Schwann cells produce a trail of prostaglandins to the original destination.
It grows within a regeneration tube.
If the potassium leak channels were suddenly blocked in a resting neuron, what would happen to its resting membrane potential? It would become more positive. It would become more negative. The RMP would be unaffected. It would hyperpolarize.
It would become more positive.
In order for muscle to continue contracting during anaerobic fermentation, which of the following is essential? Cholinesterase inhibitors Protease Myokinase Acetylcholinesterase Acid phosphatase
Myokinase
Which body system(s) is(are) dedicated to maintaining stable internal conditions by detecting and responding to stimuli? Nervous and endocrine Nervous Endocrine Nervous, endocrine, and integumentary
Nervous and endocrine
The toxin of Clostridium tetani travels within somatic motor neurons and effects the functioning of their presynaptic neurons. What effect does this have on smooth muscle? Flaccid paralysis Spastic paralysis Lockjaw No effect Myocardial atrophy
No effect
During the absolute refractory period which of the following is true? If a neuron reaches threshold, the action potential goes to completion. The neuron fires at its maximum voltage if a stimulus depolarizes the neuron to threshold. The signal grows weaker with distance. It is possible to trigger a new action potential, but only with an unusually strong stimulus. No stimulus of any strength will trigger a new action potential.
No stimulus of any strength will trigger a new action potential.
Which cells form myelin in the spinal cord? Schwann cells Astrocytes Satellite cells Oligodendrocytes Microglia
Oligodendrocytes
Which of the following is not a characteristic of a muscle cell? Plasticity Contractility Conductivity Extensibility Excitability
Plasticity
Which of the following ions has the greatest influence on the resting membrane potential? Sodium Chloride Calcium Phosphate Potassium
Potassium
What occurs during hyperpolarization of a neuron membrane? Sodium ions are entering the cells Sodium ions are leaving the cell Potassium ions are entering the cell Potassium ions are leaving the cell Both sodium and potassium ions are leaving the cell
Potassium ions are leaving the cell
Which glial cell is found wrapped around nerve fibers in the PNS? Oligodendrocytes Schwann cells Satellite cells Nodes of Ranvier Ependymal cells
Schwann cells
If a neuron is prevented from sending a neurotransmitter across a synapse to another cell, which neuron property is being inhibited? Secretion Excitability Conductivity Permeability
Secretion
Which muscle(s) can contract without the need for nervous stimulation? Skeletal muscle only Smooth muscle only Cardiac muscle only Smooth and cardiac muscle Skeletal, smooth and cardiac muscle
Smooth and cardiac muscle
Which of the following is an accurate comparison of skeletal muscle to smooth muscle? Smooth muscle contracts more slowly but relaxes more rapidly. Smooth muscle contracts more rapidly but relaxes more slowly. Smooth muscle contracts and relaxes more slowly. Smooth muscle consumes more ATP to maintain a given level of muscle tension. Smooth muscle depends on a nerve fiber to supply the calcium needed for contraction.
Smooth muscle contracts and relaxes more slowly.
Which of these does not contribute to the cessation of the signal in a synaptic transmission? Synaptic vesicles secrete neurotransmitter by exocytosis. Neurotransmitter escapes from the synapse into the nearby extracellular fluid. Neurotransmitters are no longer released. The axon terminal reabsorbs some neurotransmitters by endocytosis. Enzymes in the postsynaptic cell break down some neurotransmitters
Synaptic vesicles secrete neurotransmitter by exocytosis.
Why does one continue to breathe heavy after rigorous physical activity has stopped? The diaphragm is waiting for its acetylcholine to run out. The body requires more oxygen to restore levels of ATP and creatine phosphate. The lungs can't stop breathing until the heart rate slows down. Myosin heads need more oxygen to fully detach from actin. The kidneys require oxygen to dispose of excess lactate
The body requires more oxygen to restore levels of ATP and creatine phosphate.
What is the primary site on a neuron for receiving signals from other neurons? The axon terminals The axons The axon collaterals The neurosomas The dendrites
The dendrites
Where do most local potentials form in a neuron? The dendrites The neurosomas The axon hillock The trigger zone The Schwann cells
The dendrites
Where would you expect to find numerous gap junctions in muscular tissue? The sarcoplasmic reticulum of skeletal muscle The A bands of skeletal and cardiac muscle The sarcolemma of skeletal muscle The intercalated discs of cardiac muscle Multiunit smooth muscle
The intercalated discs of cardiac muscle
Which of the following best describes the resting membrane potential (RMP)? The intracellular environment is negatively charged. The intracellular environment has more positively charged sodium. The extracellular environment is negatively charged. It has a voltage of about +75 mV. It is dependent upon the absorption of potassium ions by the muscle fiber
The intracellular environment is negatively charged.
Which of the following is true concerning isotonic eccentric contraction? The muscle shortens but tension remains constant. The muscle lengthens but tension remains constant. The muscle tenses and shortens. The muscle tenses but length remains unchanged. The muscle lengthens and tension declines.
The muscle lengthens but tension remains constant.
Which of the following is true concerning isotonic concentric contraction? The muscle shortens but tension remains constant. The muscle lengthens but tension remains constant. The muscle tenses and shortens. The muscle tenses but length remains unchanged. The muscle lengthens and tension declines
The muscle shortens but tension remains constant.
While both systems maintain homeostasis, how does the nervous system differ from the endocrine system? The nervous system releases neurotransmitters between cells, while the endocrine system releases hormones into the blood. The nervous system releases neurotransmitters into the blood, while the endocrine system releases hormones between cells. The nervous system releases hormones between cells, while the endocrine system releases neurotransmitters into the blood. The nervous system releases hormones into the blood, while the endocrine system releases neurotransmitters between cells.
The nervous system releases neurotransmitters between cells, while the endocrine system releases hormones into the blood.
The axon terminal releases acetylcholine into the synaptic cleft, which is received by receptors on the motor end plate. Which structure does this describe? A sarcomere The thick filament The varicosity of a smooth muscle cell The neuromuscular junction of a skeletal muscle A motor unit
The neuromuscular junction of a skeletal muscle
Most metabolic and regulatory functions in a neuron happen where? The axon The neurosoma The dendrites The axon hillock The Schwann cell
The neurosoma
In order to regenerate, a peripheral nerve fiber must have which of the following? All dendrites intact At least half the length of the fiber intact At least the entire axon and neurilemma intact The neurosoma and at least some neurilemma intact At least part of the neurosoma intact
The neurosoma and at least some neurilemma intact
What happens when acetylcholine stimulates its receptors in the neuromuscular junction? The release of Ca2+ from the sarcoplasmic reticulum decreases. The permeability of the sarcolemma to Na+ increases. The positive charge on the sarcolemma decreases. The threshold of the muscle fiber lowers. The inhibitory effect of acetylcholinesterase is overridden.
The permeability of the sarcolemma to Na+ increases.
Which of the following systems would provide energy for a racquetball player, while playing a point? The respiratory system The glycolysis system The phosphagen system The anaerobic system The glycogen-lactate system
The phosphagen system
Which of these happens first in a cholinergic synaptic transmission? Acetylcholine diffuses across the synaptic cleft A postsynaptic potential is produced Sodium enters the postsynaptic cell The synaptic vesicles release acetylcholine Acetylcholine binds to ligand-regulated gates
The synaptic vesicles release acetylcholine
Which of the following is predominately made up of myosin? G actin F actin The thin filament The thick filament The elastic filament
The thick filamen
What is the purpose of the triad? The triad stores sodium. The triad synthesizes ATP. The triad maintains the resting membrane potential. The triad removes acetylcholine from the synaptic cleft. The triad allows for Ca2+ release when a muscle fiber is excited.
The triad allows for Ca2+ release when a muscle fiber is excited.
A volleyball player depends on the gastrocnemius muscles for plantar flexion, whereas a marathon runner depends more on the soleus muscles for the same action. What characteristic of the soleus muscles makes this so? They have smaller mitochondria. They have more glycogen in them. They don't have as many blood capillaries per gram of tissue. They make more use of aerobic respiration. They break ATP down to ADP and Pi faster
They make more use of aerobic respiration.
Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. How do you suppose these drugs work? They prevent calcium from entering the sarcoplasmic reticulum of smooth muscle. They stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin. They prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle. They prevent calcium from entering cardiac muscle, thus slowing down the heart rate. They prevent calcium from entering smooth muscle, thus allowing the muscle to relax.
They prevent calcium from entering smooth muscle, thus allowing the muscle to relax.
What is the purpose of motor nerve varicosities as they relate to smooth muscle? They link the thin filaments to the inside of the sarcolemma in smooth muscle. They reabsorb the decomposition products of acetylcholine after acetylcholinesterase breaks it down. They enable each cardiomyocyte to directly stimulate its neighbors. They release neurotransmitter molecules onto smooth muscle cells. They prevent single-unit smooth muscle cells from pulling apart.
They release neurotransmitter molecules onto smooth muscle cells.
Which statement best describes the goal of medications used to treat myasthenia gravis? To increase the number of acetylcholine receptors To decrease the number of synaptic vesicles To promote multiple motor unit summation To inhibit Ca2+ release from the sarcoplasmic reticulum To inhibit the function of cholinesterase
To inhibit the function of cholinesterase
Which of the following is not a purpose of the excess postexercise oxygen consumption (EPOC) in muscle? To neutralize carbon dioxide buildup To replenish the phosphagen system To oxidize lactate To serve elevated metabolic rate To restore resting levels of ATP and CP
To neutralize carbon dioxide buildup
Extensibility refers to the ability of a muscle to stretch. True False
True
Which fibers are primarily responsible for producing lactate? Type I slow oxidative fibers Type IIA intermediate glycolytic fibers Type IIB fast glycolytic fibers Type I slow-twitch fibers Red fibers
Type IIB fast glycolytic fibers
What is another name for the autonomic nervous system? Visceral sensory division Somatic sensory division Visceral motor division Somatic motor division Central nervous system
Visceral motor division
Why is the contraction strength of smooth muscle relatively independent of its resting length? It gets nearly all of its Ca2+ from the extracellular fluid. It does not have intercalated discs. It does not have sarcomeres. It is regulated by a length-tension relationship. It is involuntary muscle.
Why is the contraction strength of smooth muscle relatively independent of its resting length? It gets nearly all of its Ca2+ from the extracellular fluid. It does not have intercalated discs. It does not have sarcomeres. It is regulated by a length-tension relationship. It is involuntary muscle.
Which of the following contains overlapping thick and thin filaments? A band H band I band M line Z discs
a band
A cholinergic synapse uses __________ as its neurotransmitter. monoamine acetylcholine epinephrine norepinephrine catecholamine
acetylcholine
Nerves are __________ of the nervous system. organs tissues organ systems organelles cells
afferent; efferent
Shortening a muscle while it maintains constant tension is called __________. complete tetanus incomplete tetanus an isokinetic contraction an isometric contraction an isotonic contraction
an isotonic contraction
Loss of muscle mass from lack of activity is called __________. myopathy dystrophy apathy atrophy tetanus
atrophy
The term "nerve fiber" refers to a(n) __________. nerve cell organelle in nerve cells organ axon bundle of macromolecules in nerve cells
axon
The opening of __________ gates produces an __________. chloride; IPSP sodium; IPSP calcium; IPSP potassium; EPSP calcium and sodium; IPSP
chloride; IPSP
Even though all action potentials are the same, the brain can differentiate a variety of stimuli by source and intensity. The mechanism by which the nervous system converts these action potentials into meaningful information is called neural __________. recruitment pooling integration facilitation coding
coding
When a skeletal muscle lengthens, its __________ helps resist excessive stretching and subsequent injury to the muscle. thick filaments collagen actin troponin-tropomyosin complex varicosities
collagen
If one nerve stimulus arrives at a muscle fiber so soon that the fiber does NOT relax at all from the previous twitch, the most likely result will be __________. This can only be achieved in the laboratory. fatigue spasm incomplete tetanus complete tetanus wave summation
complete tetanus
A muscle twitch produces external tension and moves an object by shortening the muscles during the _____ phase. contraction latent twitch relaxation reload
contraction
The transfer of phosphate from CP to ADP is catalyzed by __________. myokinase creatinine cAMP creatine kinase ATP
creatine kinase
In a neuron, the opening of sodium gates typically leads to __________. repolarization of the plasma membrane hyperpolarization of the plasma membrane depolarization of the plasma membrane drifting of plasma membrane voltage toward a more negative value plasma membrane voltage returning to the resting membrane potential
depolarization of the plasma membrane
When the voltage of a plasma membrane shifts from +35 mV towards 0 mV, the cell is __________. depolarizing repolarizing hyperpolarizing reaching the threshold exiting the threshold
depolarizing
A myofilament that runs through the core of a thick filament and anchors it to a Z disc is called a(n) __________. myofibril thin filament T tubule sarcolemma elastic filament
elastic filament
All muscle types will respond to an electrical stimulus because all muscle cells are _________. excitable contractile striated involuntary isometric
excitable
A dark band formed by parallel thick filaments that partly overlap the thin filaments is known as an H band. True False
false
Acetylcholine triggers the synthesis of the second messenger cAMP only in neurons of the PNS. True False
false
Any two EPSPs will override one IPSP. True False
false
In a myelinated fiber, only the initial segment in the trigger zone has voltage-regulated channels. True False
false
In the brain, neurons are more abundant than neuroglia. True False
false
Neurons move material away from the neurosoma by retrograde transport. True False
false
Oligodendrocytes serve the same purpose in the CNS that satellite cells do in the PNS. True False
false
Skeletal muscle are attached to bones in a way that aligns proteins in an overly-stretch (lengthened) position. This lengthening facilitates the shortening of contractions. True False
false
The nervous system employs exclusively electrical means to send messages, whereas the endocrine system communicates by means of chemical messengers. True False
false
The sliding filament theory of muscle contraction has emerged from research only in the last 10 to 15 years. True False
false
When a neuron is stimulated, Na+ gates open and allow Na+ to exit the cell. True False
false
Which of the following are effectors? Receptors Stimuli Reflexes Glands Sense organs
glands
Local potentials are __________, meaning they vary in magnitude according to the strength of the stimulus. stabile graded self propagating excitatory inhibitory
graded
Local potentials are __________, whereas action potentials are __________. irreversible; reversible self-propagating; local graded; all or none nondecremental; decremental produced by voltage-regulated channels; produced by gated channels
graded; all or none
Resistance exercise will most likely cause muscle to __________. myopathy dystrophy apathy atrophy hypertrophy
hypertrophy
If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be __________. fatigue spasm incomplete tetanus complete tetanus flaccid paralysis
incomplete tetanus
The training regimen of a competitive weight lifter is designed partly to __________. convert certain parallel muscles into stronger pennate muscles increase the average number of myofibrils per muscle fiber convert white muscle tissue to red muscle increase the size of his motor units lower the threshold for muscle excitation
increase the average number of myofibrils per muscle fiber
About 90% of the neurons in the nervous system are __________ neurons. sensory motor afferent efferent inter-
inter-
A myelin sheath is composed primarily of __________. lipids carbohydrates glycoproteins proteins polysaccharides
lipids
80% of the lactate produced by skeletal muscle is converted to pyruvate by the __________. kidneys liver muscle tissue sarcoplasmic reticulum neuromuscular junction
liver
Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in __________. increased glycolysis increased use of myokinase longer aerobic respiration longer anaerobic fermentation reduced ATP consumption
longer aerobic respiration
What is the most common type of neuron? Multipolar Bipolar Unipolar Anaxonic Dendritic
multipolar
A traveling wave of excitation is known as a(n) __________. local potential graded potential action potential nerve signal depolarizing signal
nerve signal
Nerves are __________ of the nervous system. organs tissues organ systems organelles cells
organs
A skeletal muscle generates the greatest tension when it is __________. greatly stretched before being stimulated partially stretched before being stimulated fully relaxed before being stimulated well-rested and low in creatine phosphate high in lactate concentration
partially stretched before being stimulated
The sarcolemma of a resting muscle fiber is most permeable to __________. calcium potassium sodium lithium magnesium
potassium
As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must __________. recruit more muscle fibers lower its threshold reduce its wave summation shift from isometric to isotonic contraction shift from slow-twitch to fast-twitch mode
recruit more muscle fibers
The process of engaging more motor units to increase the strength of a muscle contraction is called __________. wave summation recruitment temporal summation incomplete tetanus complete tetanus
recruitment
When acetylcholinesterase outlasts the release of acetylcholine from the synaptic vesicles, the skeletal muscle __________. contracts gets stronger relaxes releases Ca2+ opens its Na+ channels
relaxes
Cardiac muscle has very little capacity for regeneration because it lacks __________. satellite cells an endomysium sarcomeres dense bodies somatic nerve fibers
satellite cells
Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source? Skeletal muscle Smooth muscle Cardiac muscle Skeletal and smooth muscle Smooth and cardiac muscle
skeletal muscle
While a neuron membrane is depolarizing its __________. chloride gates are partially open chloride gates are fully open potassium gates are fully open sodium gates are partially open sodium gates are fully open
sodium gates are fully open
A neuron can receive thousands of EPSPs from different neurons, and responds by triggering or not triggering an action potential. This addition and response to the net effect of postsynaptic potentials is called __________. temporal summation neural summation spatial summation neuronal coding recruitment
spatial summation
In skeletal muscle, the term that describes the alternating light and dark bands is ___________. strabismus striations tetanus myofibrils myoblasts
striations
The __________ division tends to prepare the body for action. sensory afferent motor afferent somatic motor parasympathetic sympatheticq
sympathetic
in __________. synaptic facilitation; short-term memory neural coding; immediate memory postsynaptic potential; long-term memory neural coding; short-term memory long-term potentiation; long-term memory
synaptic facilitation; short-term memory
To stimulate muscle contraction, acetylcholine is released from the ___________ into the synaptic cleft. synaptic vesicles junctional folds sarcoplasmic reticulum sarcolemma terminal cisterns
synaptic vesicles
The absence or inhibition of acetylcholinesterase at a synapse would lead to __________. flaccid paralysis tetanus atrophy numbness muscle wasting
tetanus
All of the following are typical characteristics of neurotransmitters except __________. they are synthesized by a presynaptic neuron they are released in response to stimulation they are released into the bloodstream before reaching the postsynaptic cell they bind to specific receptors on the postsynaptic cell they alter the physiology of the postsynaptic cell
they are released into the bloodstream before reaching the postsynaptic cell
The minimum stimulus needed to cause muscle contraction is called the __________. threshold latent period twitch motor unit innervation
threshold
The protein that acts as a calcium receptor in skeletal muscle is __________. F actin tropomyosin troponin titin dystrophin
troponin
A deficiency of acetylcholine receptors leads to muscle paralysis in myasthenia gravis. True False
true
An action potential never occurs in dendrites. True False
true
An isometric contraction does not change muscle length. True False
true
Clinically, dystrophin is the most important noncontractile protein to occur in muscle fibers. True False
true
Ependymal cells line the inner cavities of the CNS. True False
true
Memories are formed by neural pathways of modified synapses. True False
true
Most neurons have multiple dendrites. True False
true
Nitric oxide (NO) acts as a neuromodulator by altering synaptic function. True False
true
Norepinephrine is a monoamine. True False
true
Some smooth muscle is autorhythmic. True False
true
The sarcoplasmic reticulum is the smooth endoplasmic reticulum of a muscle fiber. True False
true
Unipolar neurons have only a single process leading away from the neurosoma. True False
true
The triads of a muscle fiber consist of __________. two A bands and one I band two T tubules and one terminal cistern two terminal cisterns and one T tubule two thin myofilaments and one thick myofilament two thick myofilaments and one thin myofilament
two terminal cisterns and one T tubule
The __________ division carries signals to the smooth muscle in the large intestine. visceral sensory somatic sensory visceral motor somatic motor afferent
visceral motor
Skeletal muscle is called ___________, because it is usually subject to conscious control. excitable contractile striated voluntary isometric
voluntary
Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed __________ fibers. red white intermediate fast twitch slow oxidative
white
Which of the following marks the boundaries of a sarcomere? I bands H bands Z discs M lines A bands
z discs
What is the most common inhibitory neurotransmitter in the brain? γ-aminobutyric acid (GABA) Noradrenaline Epinephrine Acetylcholine Norepinephrine
γ-aminobutyric acid (GABA)
