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210 terms

Chapter 9 & 11 A&P Theory Review

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The stimulus above which no stronger contraction can be elicited, because all motor units are firing in the muscle
maximal stimulus
The phenomenon in which the contraction of a muscle increases, due to increased Ca2+ availability and enzyme efficiency during the warm-up
Treppe
Continued sustained smooth contraction due to rapic stimulation
Tetanus
The situation in which contractions become stronger due to stimulation before complete relaxation occurs
Wave summation
How a smooth increase in muscle force is produced
multiple motor unit summation
A sarcomere is the distance between two _______.
Z discs
The _______ contains only the actin filaments.
I band
The thicker filaments are the _______ filaments
Myosin
Both actin and myosin are located in the ________.
A band
Serves as the actual "trigger" for muscle contraction by removing the inhibition of the troponin molecules.
Calcium Ions
A neurotransmitter released at motor end plates by the axon terminals.
Acetylcholine
Diffusion across the cell membrane results in depolarization
Sodium-potassium ions
Activate synaptic vesicles in axon terminals
Calcium Ions
Used to convert ADP to ATP by transfer of a high-energy phosphate group. A reserve high-energy compound
Creatine phosphate
Destroys ACh
Acetylcholinesterase
(True/False)Once a motor neuron has fired all of the muscle fibers in a muscle contract
False
(True/False)The thin filaments(actin) contain a polypeptide subunit G actin that bearts active sites for myosin attachment
True
(True/False) the force of muscle contraction is controlled by multiple motor unit summation or recruitment
True
(True/False) Eccentric contractions are more forceful than concentric contractions.
True
(True/False) A Motor neuron and all the muscle cells that it stimulates are referred to as a motor end plan.
False
(True/False) Peristalsis is characteristic of smooth muscle
True
(True/False) A contraction in which the muscle does not shorten but its tension increases is called isometric
True
(True/False) During isotonic contraction, the heavier the load, the faster the velocity of contraction
False
(True/False) During isometric contraction, the energy used appears as movement
False
(True/False) One of the important functions of skeletal muscle contractions is production of heat
True
(True/False) An increase in the calcium ion level in the sarcoplasm starts the sliding of the thin filaments. When the level of calcium ions declines, sliding stops
True
(True/False) Muscle contraction will always promote movement of body parts regardless of how they are attached
False
(True/False) Although there are no sarcomeres, smooth muscle still possesses thick and thin filaments.
True
(True/False) Muscle tone is the smallest amount of tautness or tension in the muslce due to weak, involuntary contractions of its motor units.
True
(True/False) Single-unit smooth muscle is found in the intestines.
True
(True/False) A resting potential is caused by a difference in the concentration of certain ions inside and outside the cell
True
(True/False) The effect of a neurotransmitter on the muscle cell membrane is to modify its ion permeability properties temporarily
True
(True/False) When a muscle fiber contracts, the I bands diminish in size, the H zones disappear, and the A bands move closer together but do not diminish in length
True
(true/false) Contractures are a result of a total lack of ATP
True
(true/false) Smooth muscles relax when intracellular Ca2+ levels drop but may not cease contractions
True
What is the role of tropomyosin in skeletal muscle?
A) Tropomyosin is the name of the contracting unit.
B) Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.
C) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
D) Tropomyonsin is the receptor for the motor neuron neurotransmitter.
C) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules
Which muscle cells have the greatest ability to regenerate?
A) smooth
B) cardiac
c) skeletal
d) no muscle can regenerate
A) smooth
Most skeletal muscles contain:
A) a predominance of slow oxidative fibers
B) muscle fibers of the same type
c) a mixture of fiber types
D) a predominance of fast oxidative fibers
c) a mixture of fiber types
Fatigued muscle cells that recover rapidly are the products of ___________.
a) slow exercise of short duration
b) intense exercise of long duration
c) intense exercise of short duration
d) slow exercise of long duration
c) intense exercise of long duration
The strongest muscle contractions are normally achieved by ___________.
A) increasing the stimulation up to the maximal stimulus.
B) recruiting small and medium muscle fibers
c) increasing stimulus above the threshhold
d) incrasing stimulus above the treppe threshhold
a) increasing the stimulation up to the maximum stimulus
Which of the following would be recruited later in muscle stimulation when contractile strength increases?
A) many small motor units with the ability to stimulate other motor units.
B) motor units with the longest muscle fibers
c) motor units with larger, less excitable neurons
d) large motor units with small, highly excitable neurons
c) motor units with larger, less excitable neurons
Which of the following is NOT a usual result of resistance excercise?
A) increase in the efficience of the circulatory system
B) increase in the number of muscle cells
c) increase in the number of myofibrils within the muscle cells
d) increase in the efficiency of the respiratory system.
b) increase in the number of muscle cells
Excitation-contraction coupling requires which of the following substances?
A)ATP and glucose
B) ATP only
C) Ca2+ only
d) Ca2+ and ATP
D) Ca2+ATP
Which of the following is a factor that affects the velocity and duration of muscle contraction?
A) muscle length
B) number of muscle fibers stimulated
c) load on the fiber
D) size of the muscle fibers stimulated
c) load of the fiber
Myoglobin ________.
a) stores oxygen in muscle cells
b) produces the end plate potential.
c) breaks down glycogen
d) is a protein involved in the direct phosyphorylation of ADP
A) stores oxygen in muscle cells
What structure in skeletal muscle cells functions in calcium storage?
A) sarcoplasmic reticulum
B) mitochondria
c) myofibrillar network
d) intermediate filament network
a) sarcoplasmic reticulum
What does oxygen deficit represent?
A) the amount of oxygen taken into the body immediately after the exertion
B) the amount of oxygen taken into the body prior to the exertion
c) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually needed
d) amount of energy needed for exertion
c) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually needed
Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the _______ period during which the events are excitation-contraction coupling to occur.
a) refractory
b) contraction
c) relaxion
d) latent
d) latent
Creatine phosphate functions in the muscle cell by ________.
a) inducing a conformational change in the myofilaments
b) forming a termporary chemical compound with myosin
c) storing energy that will be transferred to ADP to resynthesize ATP
D) forming a chemical compound with actin.
c) storing energy that will be transferred to ADP to resynthesize ATP
What controls the force of muscle contraction?
a) concentric contractions
b)treppe
c) multimotor unit summation
d) wave summation
c) multimotor unit summation
The major function of the sarcoplasmic reticulum in muscle contraction is to __________.
a) regulate intracellular calcium concentration.
b) make and store phospheocreatine
c) synthesize actin and myosin myofilaments
d) provide a source of myosin for the contraction process
a) regulate intracellular calcium concentration
What produces the striations of a skeletal muscle cell?
a) a sarcoplasmic reticulum
b) the arrangement of myofilaments
c) a difference in the thickness of the sarcolemma
d) the t tubules
b) the arrangment of myofilaments
which of the following are composed of myosin?
a) thick filaments
b) z discs
c) thin filaments
d) all myofilaments
a) thick filaments
During muscle contraction, myosin cross bridges attach to which active sites?
A) thick filaments
b) actin filaments
c) z discs
d) myosin filaments
b) actin filaments
which of the following surrounds the individual muscle cell?
a) perimysium
b) epimysium
c)endomysium
d) fascicle
c) endomysium
Smooth muscles that act like skeletal muscles but are controlled by autonomic nerves and hormones are _______.
a)white muscles
b) multiunit muscles
c) red muscles
d) single-unit muscles
b) multi-unit muscles
Rigor mortis occurs because_______.
a) sodium ions leak out of the muscle
b) the cells are dead
c) proteins are beginning to break down, thus preventing a flow calcium ions
d) no ATP is available to release attached actin and myosin molecules
d) no ATP is available to release attached actin and myosin
Which of the choices below does NOT describe how recovery oxygen uptake (oxygen deficit) restores metabolic conditions?
A) increases the level of lactic acid in the muscle
b) converts lactic acid back into glycogen stores in the liver
c) resynthesizes creatine phosphate and ATP in muscle fibers
d) replaces the oxygen removed from myoglobin
a) incrases the level of lactic acid in the muscle
The term aponeurosis refers to __________.
A) the bands of myofibrils
b) the sheetlike indirect attachement to a skeletal element
c) the tropomyosin-troponin complex
d) the rough endoplasmic reticulum
b) the sheetlike indirect attachment to a skeletal element
The oxygen-binding protein found in muscle cells is _________.
a) ATP
b) hemoglobin
c) immunoglobin
d) myoglobin
d) myoglobin
the contractile units of of skeletal muscles are __________.
a) myofibrils
b) t tubules
c) mitochondria
d) microtubules
myofibrils
which of the following is NOT a way muscle contractions can be graded?
a) changing the type of neurotransmitter released by the motor neuron
b) changing the frequency of stimulation
c) changing the type of muscle fibers involved in the contraction
d) changing the strength of the stimulus
c) changing the type of muscle fibers involved in the contraction
what is the functional unit of a skeletal muscle called?
A) the sarcoplasmic reticulum
b) a sarcomere
c) a myofilament
d) a myofibril
B) a sarcomere
What is the functinal role of the T tubules?
A) enhance cellular communication during muscle contraction
B) synthesize ATP to provide energy for muscle contraction
c) hold cross bridges in place in a resting muscle
D) stabilize the G and F actin
A) enhance cellular communication during muscle contraction
what is the role of calcium ions in muscle contraction?
A) increase levels of myoglobin
B) reestablish glycogen stores
c) bind to regulatory sites on troponin to remove contraction inhibition
D) form dydroxyapatite crystals
C) bind to regulatory sites on troponin to remove contraction inhibition
The warm-up period required of athletes in order to bring their muscles to peak performance is called __________.
A) incomlete tetanus
B) twitch
c) treppe
D) wave summation
C) Treppe
The main effect of the warm up period of athletes, as the muscle contractions increase in strength, is to ________.
A) convert glycogen to glucose
B) enhance the availability of calcium and efficiency of enzyme system
c) tone the muscles and stabilize the joints for workout.
D) increase the myoglobin content
B) enhance the availability of calcium and the efficiency of enzyme systems
During rigorous exercise there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to __________.
A) stearic acid
B) hydorchlorid acid
C) a strong base
D) lactic acid
D) lactic acid
When a muscle is unable to respond to stimuli temporily, it is in which of the following periods?
A) fatigue period
B) refractory period
C) laten period
D) relaxation period
B) refractory period
In an isotonic contraction, the muscle ________.
A) changes in length and moves the "load"
B) never converts pyruvate to lactate
c) rapidly resynthsizes creatine phosphate and ATP
D) does not change in length but increases tensions
A) changes in length and moves the "load"
The muscle cell membrane is called the________.
A) epimysium
B) endomysium
C) perimysium
D) sarcolemma
D) sarcolemma
Which of the following is the correct sequence of events for muscle contractions?
A) motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments
B) neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP driven power stroke.
C) neurtotransmitter release, muscle cell action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke
D) muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, slid
C
A) motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments.
The mechanism of contraction in smooth muscle is different from skeletal muscle in that _________.
A)the site of calcium regulation differs
B) the trigger for contraction is a rise in intracellular calcium
C) ATP energizes the sliding process
D) actin and myosin interact by the sliding filament mechanism.
A)the site of calcium regulation differs
Which of the following describes the cells of single-unit visceral muscle?
A) they exhibit spontaneous action potential
B) they are chemically coupled to one another by gap junctions.
C) the contract all at once
D) they consist of muscle fibers that are structurally independent of each other
A) they exhibit spontaneous action potential
Which of the following is not a role of ionic calcium in muscle in muscle in muscle contraction?
A)promotes breakdown of glycogen and ATP synthesis
B) triggers neurotransmitter secretion
c) removes contraction inhibitor
D) activates epinepherine released from adrenal gland
D) activates epinepherine released from adrenal gland
Which of the following is try about smooth muscle contraction?
A) Smooth muscle cannot stretch as much as skeletal muscle
B) Certain smooth muscle cells can actually divide to increase their numbers
C) Smooth muscle has well developed T tubules at the site of invagination
d) Smooth muscle, in contrast to skeletal muscle, cannot synthesize or recrete any connective tissue elements
B) certain smooth muscle cells can actually divide to increase their numbers
Smooth muscle is characterized by all of the following except ___________.
A) thre are more thick filaments than thin filaments.
B) there are no sarcomeres
c) there are noncontractile intermediate filaments that attach to dense bodies within the cell
D) it appears to lack troponin
A) there are more thick filaments than thin filaments.
Muscle tissue has all of the following properties except__________.
A) secretion
B) extensibility
C)excitability
D)contractility
A)secretion
The giant protein titin maintains the organization of the _________ assisting in muscle stretching.
A) Z disc
B) M line
C) I band
D) A band
D) A band
Which of the following statements is true?
A) Cardiac muscle cells are found in the heart and large blood vessels
B) Smooth muscle cells have T tubules
C) Striated muscle cells are long and cylindrical with many nuclei
D) Cardiac muscle cells have many nuclei
C) Striated muscle cells are long and cylindrical with many nuclei
An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is _________.
A) hydrolysis
B) the electron transport chain
C) the citric acid cycle
D)glycolysis
D) glycolysis
Muscle tone is _________.
A) the condition of athletes after intensive training
B) the feeling of well being following exercise
C) a state of sustained muscle contraction
D) the ability of a muscle to efficiently cause skeletal contractions.
C) a state of sustained muscle contraction
The sliding filament model of contraction involves _________.
A) actin and myosin but not sliding past each other
B) the shortening of thick filaments so that thin filaments slide past
C) the Z discs sliding over the myofilaments
D) actin and myosin sliding past each other and partially overlapping
D) actin and myosin sliding past each other and partially overlapping
After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?
A) acetylcholinersterase destroying the ACh
B) calcium ions returning to the terminal cisternae
C) the tropomyosin blocking the myosin once full contraction is achieved
D) the action potential stops going down the overloaded T tubules
A) acetylcholinersterase destroying the ACh
Which of the following statements is most accurate?
A) Muscle tension remains relatively constant during isotonic contraction
B)the I band lengthens during isotonic contraction
C) T tubules may be sliding during isotonic contraction
D) myofilaments slide during isometric contractions
A) Muscle tension remains relatively constand during isotonic contraction
What is the most distinguishing characteristic of muscle tissue?
A) the sarcoplasmic reticulum
B) the ability to transform chemical energy into mechanical energy
C) the diversity of activity of muscle tissue
D) the design of the fibers
B) the ability to transform chemical energy into mechanical energy
Three discrete types of muscle fibers are identified on the basis fo their size, speed, and endurance. Which of the following athletic endeavors best represents the use of red fibers?
A) a sprint by and Olympic runner
B) a long relaxing swim
C) mountain climbing
D) playing baseball or basketball
B) a long relaxing swim
Of the following muscle types, which has only ONE nucleus, NO sarcomeres, and rare gap junctions?
A) skeletal muscle
B) multiunit smooth muscle
C) cardiac muscle
D) visceral smooth muscle
B) multiunit smooth muscle
Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, _______.
A) cross bridge attachment would be optimum because of all the free binding sites on actin.
B) maximum force production would result because the muscle has a maximum range of travel
C) no muscle tension could be generated
D) ATP consumption would increase because the sarcomere is "trying" to contract
C) no muscle tension would be generated
What part of the sarcolemma contains acetylcholine receptors?
A)part adjacent to another muscle cell
B) motor end plate
C) any part of the sarcolemma
D) end of the muscle fiber
B) motor end plate
Which of the following statements is false of incorrect?
A) Cardiac muscle fibers can use lactic acid to make ATP
B) Cardiac muscle fibers depend mostly on anaerobic cellular respiration to generate ATP
C) Under normal resting conditions, cardiac muscle tissue contracts and relaxes about 75 times per minute.
D) Cardiac muscle contracts when stimulated by its own autorythmic muscle cells
B) Cardiac muscle fibers depend mostly on anaerobic cellular respiration to generate ATP
Only _______ muscle cells are always multinucleated.
Skeletal
Claudication might more simply be called _______.
Limping
The end of the muscle that typically moves when a muscle contracts is called the _________.
insertion
In the synaptic cleft of a neuromuscular junction, an enzyme called __________ is always present.
Acetylcholinesterase
The time is which cross bridges are active is called the period of _________.
Contraction
________(color) fibers are slow (oxidative) fibers.
Red
Only ______ muscle cells commonly branch.
cardiac
A smooth, sustained contraction is called _______.
Tetanus
Define physiological fatigue
fatigue occurs when ATP production fails to keep pace with ATP use even though the muscle still recieves stimulus
Compare red and white muscles relative to their speed of action and endurance.
Red muscles tend to have a slow(oxidative) rate and fatigue resistance, whereas white muscle cells have a fast(oxidative) rate and fatigue early
Briefly, what causes rigor mortis?
follwing the death of an individual, ATP is rapidly consumed and cannot be replaced. Because cross bridge detachment and calcium active transport is ATP driven, calcium leakage from the sarcoplasmic reticulum cause attachment of cross bridges, and lack of ATP prevents detachments.
What ulitmately stops muscle stimulation when the motor neuron ceases firing?
The ultimate switch is the enzymes acetycholinesterase. When the neuron stops releasing ACh, the muscle would not stop contracting if the acetylcholinesterase did not split the ACh into its two components, acetyl and choline, making them release their binding sites.
A long-distance runner is about to enter a 5 mile race. Beforehand, he spends several minutes warming up. During the warm-up period, the phenomenon of treppe is occurring in the body muscles being used. What is treppe and why does it occur?
Treppe is the staircase phenomenon in which muslces increase their strength of contraction due to increased availability of calcium. Additionally, the increased warmth due to activity causes an increase in the efficience of muscle enzyme systems.
Skeletal muscles have two special inclusions that help them perform their function of movement. What are the two special inclusions of skeletal muscle cells and how would the be useful to the cell?
Skeletal muscle cells require a lot of rapidly available fuel to burn in order to function properly they also require a lot of oxygen to burn this fuel efficiently. Glycosomes store glycogen that can be quickly converted to glucose, which in turn can be burned to produce ATP. Myoglobin is a chemical much like hemoglobin in blood cells that can store large quanities of oxygen.
What are the parts of the skeletal muscle triad and what are their functions?
The sarcoplasmic reticulum is a reservoir for calcium ions in the cells normal resting state. The T tubule is a fold in the cell membrane between the sarcoplasmic reticuli. When an impulse is activated by a motor neuron, the voltage regulated change causes SR foot proteins to open Ca2+ channels. The calcium ions are flushed out where they interact with the troponin complex to initiate a contraction. Once the axon stops firing, the membrane polarity is quickly restored and the calcium ions are pulled off the troponin and attracted back into the sarcoplasmic reticulum
Briefly explain the sources of energy for a one-minute sustained muscle contraction
1. The first 4-6 seconds of energy comes from stored ATP in the muscle cell.
2. 6-15 seconds of energy come from the transfer of creatine phosphate and ADP(which comes from the first few seconds of burn) to form additional ATP
3. 15-60 seconds of energy come from glycolysis, which by now has begun full production of ATP from glucose
What are caveolae?
Folds on the surface of smooth muscle cells that correspond to T tubules in skeletal muscle cells
How is it that norepinepherine(NE) can inhibit smooth muscle action in airways, yet stimulate contraction in smooth muscle everywhere else in the body?
Airway passages have smooth muscle cells that are unique in that they have two receptor sites on their outer membrane. One receptor site accepts ACh as the neurotransmitter. When exicted it causes the smooth muscle to contract. The second site accepts NE and the inhibitory effect is that the ACh dilates the airway
How do the three muscle types respond to being stretched?
All three muscle types initially respond by contracting more forcefully. However, in smooth muscle cells the increased tension persists only briefly, and the muscle adapts to its new length and relaxes
What is agrin?
Agrin is a growth factor of developing muscles. Agrin stimulates ACh receptors to cluster around a newly forming motor end plate.
The neuron cannot respond to a second stimulus, no matter how strong.
Absolute refractory period
The interior of the cell becomes LESS negative due to an influx of sodium ions.
Depolarization
The specific period during which potassium ions diffuse out of the neuron due to a change in membrane permeability
Repolarization
Also called a nerve impulse transmitted by axons
Action potential
An exceptionally strong stimulus can trigger a response
Relatively refractory period
Numerous nerve impulses arriving at a synapse at closely timed intervals exert a cumulative effect
Temporal summation
Stimulation of a postsynaptic neuron by many terminals at the same time.
Spatial summation
An insufficient stimulus
Subthreshhold stimulus
Any stimulus below this intensity will result in no reponse in a neuron
Threshold stimulus
Area where nerve impuse is generated
Trigger zone
Recieves stimuli
Receptive region
Plasma membraned exhibits voltage gated Na+ and K+ channels
conducting region
Plasma membrane exhibits voltage gated Ca+ channels
secretory region
Axon terminals release neurotransmitters
Secretory zone
Plasma membrane exhibits chmically gated ion channels
receptive region
One incoming fiber triggers reponses in ever-increasing numbers farther and father along the circuit
Diverging circuit
May be involved in complex, exacting types of mental processing
parallel after discharge circuit
Involved in control of rhythmic activities such as breathing
reverberating circuit
Involved in activating fibers of a skeletal muscle such as the biceps muscle
Diverging circuit
Different types of sensory input can have the same ultimate effect
converging circuit
increases acid secretion in the stomach; blocked by cimetidine
histamine
"feel good" neurotransmitter
norepinepherine
Mediates pain
Substance P
Principle inhibitory neurotransmitter of the spinal cord
Glycine
Natural opiates that inhibit pain, effect mimicked by morphine
endorphines
(t/f) the all or none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place
False
Reflexes are rapid, automatic responses to stimuli (T/F)
True
Efferent nerve fibers may be described as motor nerve fibers (T/F)
True
Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system. (T/F)
True
Myelination of the nerve fibers in the central nervous system is the job of the oligodendrocyte(T/F)
True
During depolarization the inside of the neurons membrane becomes less negative(t/f)
True
Neurons in the CNS are organized into functional groups(t/f)
True
Strong stimuli case the amplitude of action potenals generated to increase(t/f)
False
The oligodendrocytes can myelinate several axons(t/f)
True
Enkephalins and endorphines are peptides that act like morphine(t/f)
True
In myelinated axons the voltage regulated sodium channels are concentrated at the nodes of Ranvier(t/f)
True
A postsynaptic potential is a graded potential that is the result of neurotransmitter released into the synapse between two neurons(t/f)
True
Large diameter nerve fibers conduct impulses much faster than small diameter fibers (t/f)
True
The nodes of Ravier are found only on myelinated, peripheral neuron processes(t/f)
false
Unipolar neurons have axons structurally divided into peripheral and central processes(t/f)
True
A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vessels to the axonal membrane(t/f)
True
If bacteria invaded the CNS tissue, microglia woiuld migrate to the area to engulf and destroy them. (t/f)
True
Which of the following is NOT a function of astrocytes?
A) provide the defense for the CNS
B) guide the migration of young neurons, synapse formation, and helping to determind capillary permeability
C) control the chemical environment around neurons
D) anchor neurons to blood vessels
E) support and brace neurons
A) provide the defense for the CNS
Which of the following choices below describe the ANS?
A) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
B) sensory and motor neurons that supply the digestive tract
C) motor fibers that conduct nerve impulses from the CNS to skeletal muscles
D) sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste and smell to the CNS
A) motor fibers taht conduct impulses from the CNS to smooth muscle, cardiac muscle and glands
What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid called?
A) oligodendrocytes
B) astrocytes
C) Schwann cels
D) ependymal cells
D) epenymal cells
The sheath of Schwann is also called the _______.
A) myelin sheath
B) white matter
C) axolemma
D) neurilemma
D) neurilemma
Bipolar neurons are common______.
A) found in the ganglia
B) motor neurons
C) called neuroglial cells
D) found in the retina of the eye
D) found in the retina of the eye
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?
A) norepinephrine
B) acetylcholine
C) cholinesterase
D) gamma aminobutyric acid
B) acetylcholine
In what way does the interior surface of a cell membrane of a resting(nonconducting) neuron differ from the external environment? The interior is ______.
A) positively charged and contains more sodium
B) positively charged and contains less sodium
C) negatively charged and contains less sodium
D) negatively charged and contains more sodium
C) negatively charged and contains less sodium
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon______.
A) muscle contraction would occur
B) the impulse woud move to the axon terminal only
C) the impulse would spread bidirectionally
D) the impulse would move to the axon terminal only and the muscle contraction would occur
C) the impulse would spread bidirectionally
Neurons may be classified according to several characteristics. Which of the following is correct?
A) Group A fibers are mostly somatic sensory and motor and are the smallest diameter
B) Group C fibers are not capable of saltatory conduction
C) A small cross sectional area allows shorter conduction times
D) Group B fibers are highly myelinated and have the highest conduction velocities
B) Group C fibers are not capable of saltatory conduction
Select the correct statement about serial processing.
A) Smells are processed by serial pathways
B) Input travels along several different pathways
C) Memories are triggered by serial processing
D) Spinal reflexes are an example of serial processing
D) Spinal reflexes are an example of serial processing
The part of the nervous system that is voluntary and conducts impulses from the CNS to the skeletal muscles is the ______ nervous system.
Somatic
______ are found in the CNS and bind axons and blood vessels to each other.
Astrocytes
A gap between Schwann cells in the peripheral system is called a(n)______.
Node of Ranvier
What mechanism is responsible for axonal transport?
ATP-dependent "motor" proteins such as kinesin, dynein, and myosin are responsible. They propel cellular componens along microtubules.
The synapse more common in embyonic nervous tissue than in adults is the ______.
electrical synapse
When information is delivered within the CNS simultaneously by different part of the neural pathway, the process is called ______ processing.
parallel
______ potentials are short-lived, local changes in membrane potential that can be either depolarized or hyperpolarized.
Graded
______ is a disease that gradually destroys the myelin sheaths of neurons in the CNS, particularly in young adults.
Multiple sclerosis(MS)
When one or more presynaptic neurons fire in rapid order it produces a much greater depolarization of the postsynaptic membrane that would result from a single EPSP; this event is called ______ summation.
Temporal
What is the role of microglial cells and why are they so important in the CNS?
In the presence of invading microbes, microglial cells become macrophages to phagocytize the microbes and neuronal debris. This protective role is important because cells of the immune system are denied access to the CNS.
Define neurotransmitter. Name two amino acid neurotransmitters, two catecholamines, and two peptides.
Neurotransmitters are chemical signals used as a means of communication. GABA and glycine are amino acid neurotransmitters, dopamine and norepinepherine are catecholamines, and endorphin and enkephalin are peptide transmitters
What function is served by the increased axon diameter at the node of Ravier?
Increased diameter results in increased surface areaon the membrane for sodium channels. This results in increased speed of impulse propagation.
Imagine a neuron that has several hundred axonal knobs impinging on it. The majority of these axonal knobs are shown to be "firing". However, the neuron in question does not transmit an impuse. Give a valid explanation of why this could occur.
Both excitatory and inhibitory potentials impinge on neurons. Inhibatory postsynaptic potentials(IPSPs) are "firing" but due to the neurotransmitter released and its action, the postsynaptic neuron is inhibited from "firing" (hyperpolarized)
What are the basic divisions of the peripheral nervous system?
Sensory and motor divisions. Motor has two divisions, the somatic and autonomic. The autonomic has two divisions has two divisions the sympathetic and parasympathetic.
How can a single axon respond to several different kinds of events?
Some axon terminals contain more that one kind of neurotransmitter. Therefore, the axon can release one or more neurotransmitters simultaneously, creating singular or multiple events.
Because all action potentials are alike, how does the brain separate situations that require immediate attention from ordinary "positional" reports?
The importance of a stimulus is derived from the number of stimuli recieved from the same source. The frequency of impulse transmission indicates the stimulus intensity and the brain reponds appropriately.
ATP neurotransmitters have what basic effect on the body?
The provoke a sensation of pain
How can potentially poisonous gases like NO and CO be used in the body?
These gases are neurotransmitters that act indirectly. Similar to hormones, NO and CO promote longer lasting effects by acting through intracellular second message molecules
Which patter of neural processing is important for higher level mental processing such as problem solving?
Parallel processing
Multiple sclerosis is a disease in which the myelin sheaths are destroyed. What process does this interfere with and what would be the consequence?
Demyelination interferes with saltatory conduction, which would result in a slowing down of nerve impulse propagation
Which of the following describes the nervous system integrative fuction?
A) responds to stimuli by gland secretion or muscle contraction
B) senses changes in the environment
C) analyzes sensory information, stores information, makes decisions
C) analyzes sensory information, stores information, makes decisions
The period after an initial stimulus when a neuron is NOT sensitive to another stimulus is the ______.
A) Resting period
B) repolarization
C) absolute refactory period
D) depolarization
C) absolute refactory period
Which of the following is NOT a special characteristic of neurons?
A) they have extreme longevity
B) They conduct impulses
C) They are mitotic
D) They have an exceptionally high metabolic rate
C) they are mitotic
The part of a neuron that conducts impulses away from its cell body is called a(n)______.
A) Dendrite
B) neurolemma
C) Schwann Cell
D) axon
D) axon
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?
A) leakage channel
B) mechanically gated channel
C) ligand gated channel
D) voltage gated channel
D) voltage gated channel
An impulsem from one nerve cell is communicated to another nerve cell via the ______.
A) effector
B) receptor
C) cell body
D) synapse
D) synapse
What is the role of acetylcholinesterase?
A) stimulate the production of serotonin
B) act as a transmitting agent
C) amplify or enhance the effect of ACh
D) destroy ACh a brief period after its release by the axon endings
D) destroy ACh a brief period after its release by the axon endings
Which of the following is NOT a fucntion of the autonomic nervous system?
A) innervation of the skeletal muscle
B) innervation of smooth muscle of the digestive tract
C) inervatoin of cardiac muscle
D) innervation of glands
A) innervation of the skeletal muscle
Collections of nerve cell bodies outside the central nervous system are called ______.
A) ganglia
B) nuclei
C) nerves
D) tracts
A) ganglia
The term central nervous system refers to the ______.
A) spinal cord and spinal nerves
B) autonomic nervous system
C) brain and spinal cord
D) brain, spinal cord and peripheral nerves
C) brain and spinal cord
The substance released at axon terminal to propagate a nervous impulse is called a(n)______.
A) biogenic amine
B) cholinesterase
C) neurotransmitter
D) ion
C) neurotranmitter
A neuron that has as its primary function the job of connecting other neurons is called a(n)______.
A) association neuron
B) efferent neuron
C) glial cell
D) afferent neuron
A) association neuron
Saltatory conduction is made possible by ________.
A) large nerve fibers
B) the myelin sheath
C) diphasic impulses
D) erratic tranmission of nerve impulses
B) the myelin sheath
Which of the following is NOT a chemical class of neurotransmitters?
A) neucleic acid
B) biogenic amine
C) acetylcholine
D) amino acid
E) ATP and other purines
A) neucleic acid
Which of the following is false or incorrect?
A) a nerve impulse occurs if the excitatory and inhibitory effects are equal
B) an inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane
C) an excitatory postsynaptic potential occurs if the exictatory effect is greater than the inhibatory effect but less than threshhold
A) a nerve impulse occurs if the excitatory and inhibitory effects are equal
Select the correct statement regarding synapses:
A) The release of neurotransmitter molecules gives cells the property of bing electronically coupled
B) the synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
C) Neurotransmitter recptors are located on the axons of cells
D) Cells with interconnected cytoplasm are chemically coupled
B) the synaptic cleft prevents an impulse from being transmited directly from one neuron to another
Ependymal cells ______.
A) are a type of neuron
B) are the most numerous of the neuroglia
C) help to circulate the cerebrospinal fluid
D) are a type of macrophage
C) help to circulate cerobrospinal fluid
Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are _______>
A) astrocytes
B) oligodendrocytes
C) Schwann Cells
D) microglia
A) astrocytes
Schwann cells are functionally similar to _______.
A) ependymal cells
B) oligodendrocytes
C) astrocytes
D) microglia
B) oligodendrocytes
Immediately after an action potential has peaked, which cellular gates open?
A) potassium
B) calcium
C) chloride
D) sodium
A) Potassium
Nerve cell adhesion molecules (N-CAMs)______.
A) are crucial in the production of neurtransmitters
B) release growth factor
C) are found on "pathfinder" neurons
D) are crucial for the development of neural connections
D) are crucial for the developement of neural concctions
An inhibitory postsynaptic potential (PSP) is associated with _______.
A) a change in sodium ion permeability
B) lowering the threshhold for an action potential to occur
C) opening of voltage regulated channels
D) hyperpolarization
D) hyperpolarization
Which of the following will occur when an excitatory postsynaptic potential (ESP) is being generated on the dendritic membrane?
A) A single type of channel will open permitting simulataneous flow of sodium and potassium
B) Sodium gates will open first, then close as potassium gates open
C) Specific sodium gates will open
D) Specific potassium gates will open
A) A single type of channel will open permitting simulateous flow of sodium and potassium
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a _______.
A) action potential
B) excitatory potential
C) postsynaptic potential
D) generator potential
D) generator potential
Which of the follwing is NOT true of graded potential?
A) they are short lived
B) they increase amplitude as they move away from the stimulus point
C) they can form on receptor endings
D) they can be called postsynaptic potentials
B) they increase implitude as they move away from the stimulus point
Which of the following is true about the movement of ions across excitable living membrane?
A) Some ions are prevented from moving down their concentration gradients by ATP driven pumps
B) the bulk of the solution inside a cell are negatively charged
C) ions always move actively across membranes through leakage channels
D) Sodium gates in the membrane can opne in response to electrical potential changes
A) some ions are prevented from moving down their concentration gradients by ATP driven pumps
A second nerve impulse cannot be generated until _______.
A) the Na ions have been pumped back into the cell
B) all sodium gates are closed
C) the membrane potential has been reestablished
D) proteins have been resynthesized
C) the membrated potential has been reestablished