HAP Unit 07
Choose the answer that lists the steps that sequentially follow the influx of calcium ions into the cytosol and exposure of actin binding sites: 1. The myosin head binds to actin, which results in the release of ADP and Pi. 2. The power stroke of the myosin head results in the thin filament sliding toward the center of the sacromere. 3. Calcium ions are transported back into the terminal cisternae. 4. Hydrolysis of ATP leads to the re-energizing and repositioning of the myosin head. 5. ATP binds to the myosin head, which releases the myosin head from actin. 1, 2, 5, 4, 3 5, 4, 3, 2, 1 3, 1, 2, 4, 5 1, 2, 3, 4, 5
1, 2, 5, 4, 3
How many major muscle groups are there in the human body? 640 8 12 3
121
Which type of activity would a runner who has more Type I muscle fibers than Type II participate in? triathlon that includes a five mile run 27 mile marathon All answers are correct. 100 meter run
27 mile marathon
Place the following steps in order from first to last. 1. Diffusion of acetylcholine across the synaptic cleft. 2. Binding of acetylcholine to its receptor. 3. Arrival of an action potential (electrical impulse) to the axon terminal of the motor neuron . 4. Release of acetylcholine. 6. Generation of an action potential at the motor end plate region. 5. Release of calcium from the terminal cisternae of the sarcoplasmic reticulum 4, 3, 1, 6, 2 ,5 3, 4, 1, 6, 5, 2 3, 4, 1, 2, 6, 5 1, 2, 3, 4, 5, 6
3, 4, 1, 2, 6, 5
Which statement about myosin is CORRECT? Myosin never changes shape. A single thick filament contains many myosin molecules. Myosin has three energy states: high, medium, and low. Myosin has actin binding sites located on its tail region.
A single thick filament contains many myosin molecules.
What must bind to the cross bridge for it to disconnect from the actin molecule? Tropomyosin Calcium ATP Troponin
ATP
Which molecule is NOT a component of the thin filament? Actin Troponin ATP Tropomyosin
ATP
Which molecule is responsible for moving the calcium back into the terminal cisternae (sarcoplasmic reticulum)? ATP Actin Troponin Myosin
ATP
Which molecule stores and releases chemical energy within the cell? ATP Tropomyosin Troponin Myosin
ATP
In the presence of oxygen, the final metabolic products of aerobic respiration are ____________________. ATP, water and carbon dioxide. myoglobin. lactic acid. muscle fatigue.
ATP, water and carbon dioxide.
What neurotransmitter is located in the synaptic vesicles of the motor neuron? GABA Norepinephrine Acetylcholine (ACh)
Acetylcholine (ACh)
How is acetylcholine removed from the synaptic cleft? There is a reuptake pump for acetylcholine on the presynaptic membrane. Acetylcholinesterase, an enzyme, digests the acetylcholine. Acetylcholine simply diffuses away from the synaptic cleft.
Acetylcholinesterase, an enzyme, digests the acetylcholine.
The head of the myosin molecule binds to what molecule to form the cross bridge? Actin Tropomyosin Troponin
Actin
Which of the following processes produces the most ATP? Hydrolysis of creatine phosphate Anaerobic respiration Aerobic respiration
Aerobic respiration
Calcium___ is stored in the terminal cisternae of the sarcoplasmic reticulum. regulates actin and myosin binding. bound to troponin will cause a conformational change in the troponin-tropomyosin complex. All answers are correct.
All answers are correct.
Connective tissue coverings of skeletal muscle function to ____________________. provide strength and support to the entire muscle. bind muscle cells together. give rise to tendons. All answers are correct.
All answers are correct.
Glucose ____________________. is broken down to produce ATP is stored in the muscle cell in the form of glycogen. All answers are correct. is transported to the muscle cell via the blood.
All answers are correct.
To end a contraction ____________________. neurotransmitter is no longer released. All answers are correct. actin binding sites must be covered by tropomyosin. calcium is moved back into the terminal cisternae via calcium pumps.
All answers are correct.
Variables affecting the strength and degree of muscle contraction include ____________________. All answers are correct. the number of muscle cells per motor unit. the number of myofilaments present within the muscle cells. the number of motor units firing at the same time.
All answers are correct.
Which statement is TRUE? All muscle cells are striated. All muscle cells are identical. All muscle cells are considered to be contractile tissue. All muscle cells are voluntary.
All muscle cells are considered to be contractile tissue.
Which statement is TRUE? Motor units may act independently of each other. The nervous system controls muscle cell stimulation. All statements are true. A motor unit is composed of a motor neuron and all the cells it stimulates.
All statements are true.
Which event IMMEDIATELY precedes calcium release from the terminal cisternae? ATP hydrolyzes into ADP and Pi The opening of chemically regulated calcium channels Troponin-tropomysin complex moves to expose actin binding site Arrival of an action potential
Arrival of an action potential
What is the cause of rigor mortis? Calcium influx into the cell after death Diffusion of potassium out of the cell after death Breakdown of protein in the cell after death High levels of sodium in the cell after death
Calcium influx into the cell after death
Which classification is NOT used to group types of muscle? Whether the cell is under voluntary or involuntary control Number and position of nuclei in each cell Presence of striations Cell shape Cell size
Cell size
When a stimulus is applied to a muscle in such a manner that each contraction wave fuses into a single continuous peak, the muscle is exhibiting what? Fatigue Wave summation Complete tetanus Treppe
Complete tetanus
Match the following terms with the correct definition. Deltoid Trapezius Grasilis Platys Piriformis Obicularis Serratus A. Triangle shaped B. Trapezoid shaped C. slender D. Flat E. Square shaped F. Circular G. Saw-toothed shaped
Deltoid A. Triangle shaped Trapezius B. Trapezoid shaped Grasilis C. slender Platys D. Flat Piriformis E. Square shaped Obicularis F. Circular Serratus G. Saw-toothed shaped
What is the cause of rigor mortis? Lack of an action potential Depletion of ATP No calcium available to bind to troponin
Depletion of ATP
A muscle can contract at just one strength. True False
False
All motor neurons stimulate exactly the same number of muscle cells. True False
False
Each thick filament is composed of a single myosin molecule. True False
False
If a motor neuron is damaged permanently the muscle cell it stimulates can contract normally. True False
False
If a muscle fiber has few mitochondria and low capillary density, it is prepared to synthesize ATP aerobically. True False
False
Increased levels of intracellular potassium result in the contraction of the skeletal muscle cell. True False
False
Muscle cells have very large ATP stores so they do not have to replace ATP used during contraction. True False
False
Skeletal muscle cells do not require nervous system input to function. True False
False
The strength of a muscle contraction cannot be altered by changing the starting length of the muscle. True False
False
There are two types of muscle fibers, Type I (fast twitch) and Type II (slow twitch) True False
False
Type II muscle fibers primarily synthesize ATP aerobically. True False
False
Which statement is CORRECT? If an adequate stimulus is applied to muscle cells, a twitch will occur. The gastrocnemius and bricep brachii twitch patterns are identical. A muscle twitch does not generate any muscle tension.
If an adequate stimulus is applied to muscle cells, a twitch will occur.
With rapid, multiple stimulations, the contraction-relaxation cycles are shorter but there still is some degree of relaxation. What is this stage called? Treppe Complete tetanus Incomplete tetanus Wave (temporal) summation
Incomplete tetanus
Which is NOT a role of ATP during muscle contraction? It binds to troponin, which results in a conformational change. It is required for calcium transport back into the sarcoplasmic reticulum. It energizes the power stroke of the myosin head. It disconnects the myosin head from the binding site of actin when the power stroke is complete.
It binds to troponin, which results in a conformational change.
What is the end product of anaerobic respiration that leads to fatigue? Acetyl CoA Pyruvic acid Lactic acid
Lactic acid
Cyanide is a molecule known to block ATP synthesis. Which organelle(s) would cyanide poisoning affect directly? Mitochondria Nucleus Sarcoplasmic reticulum T-tubules
Mitochondria
Which statement is CORRECT? Overstretching rarely occurs in skeletal muscle. Overstretched muscle is characterized by thin and thick filaments overlapping. Moderately stretched muscles fatigue quickly. Unstretched muscle will contract less forcibly than moderately stretched muscle.
Moderately stretched muscles fatigue quickly.
The thick filament is composed of what molecule? Actin Tropomyosin Myosin Troponin
Myosin
Which molecule has two heads and a tail? Myosin Troponin Tropomyosin Actin
Myosin
Match each step of the cross bridge cycle to its correct statement. Myosin head Troponin Contractile Proteins Power-stroke Tropomyosin A. Flexing movement of the myosin head pulls the thin filament toward the center of the sarcomere. B. Thick and thin filaments interact to produce a shortening of a sarcomere. C. Globular head of the myosin molecule. D. A complex of three small proteins that binds calcium. E. The protein molecule that entwines around the actin molecule and blocks the myosin binding site.
Myosin head C. Globular head of the myosin molecule. Troponin D. A complex of three small proteins that binds calcium. Contractile Proteins B. Thick and thin filaments interact to produce a shortening of a sarcomere. Power-stroke A. Flexing movement of the myosin head pulls the thin filament toward the center of the sarcomere. Tropomyosin E. The protein molecule that entwines around the actin molecule and blocks the myosin binding site.
Match the following terms with the correct definition Rectus Transverse Oblique Magnus Minor Longus Lattisumus A. Parallel to the midline B. Perpendicular to the midline C. Diagonal to the midline D. Large E. Small F. Long G. Widest
Rectus A. Parallel to the midline Transverse B. Perpendicular to the midline Oblique C. Diagonal to the midline Magnus D. Large Minor E. Small Longus F. Long Lattisumus G. Widest
Sarcomeres lengthen during which phase/period of muscle twitch? Latent period Relaxation phase Contraction phase
Relaxation phase
Match each term with its description. Synaptic Vesicles Axon Terminal Motor End Plate Synaptic Cleft A. A folded region of the sarcolemma at the neuromuscular junction. B. Small membranous containers located within the axon terminal. C. The physical space that exists between the axon terminal and the motor end plate. D. The enlarged, distal end of a motor neuron axon (process).
Synaptic Vesicles B. Small membranous containers located within the axon terminal. Axon Terminal D. The enlarged, distal end of a motor neuron axon (process). Motor End Plate A. A folded region of the sarcolemma at the neuromuscular junction. Synaptic Cleft C. The physical space that exists between the axon terminal and the motor end plate.
Depolarization of the motor endplate causes an action potential to travel down the muscle cell membrane and enter the muscle cell through what passageway? Terminal cisternae T tubule Sacrolemma
T tubule
Which statement is FALSE? The motor endplate region of the sarcolemma is located between two adjacent T-tubules. A neuromuscular junction is composed of axon terminal, synaptic cleft, and motor endplate. T-tubules are also known as sarcoplasmic reticulum cisternae. A synaptic cleft is a physical space between the axon terminal and sarcolemma.
T-tubules are also known as sarcoplasmic reticulum cisternae.
When a second stimulus is applied before complete relaxation, there is a greater development of tension. What is this called? Asynchronous motor unit summation Treppe Multiple motor unit summation Temporal summation
Temporal summation
The arrangement of the thick and thin myofilaments forms light and dark bands along the myofibril. The length of the thick filament corresponds with which band? The I band The A band The B band
The A band
The length of which band decreases as the muscle contracts? The I band The A band The B band
The I band
All of the following factors affect muscle tension EXCEPT: Degree of muscle stretch Frequency of stimulation The all-or-none contraction of muscle cells Number of motor units recruited
The all-or-none contraction of muscle cells
If a muscle's threshold stimulus is 1.0 volt, what will occur if 2.0 volts is applied? The contraction will be of greater force, but not twice as great as occurred with the 1.0 V stimulus. The time between contractions will decrease by half. The muscle will fatigue instantly. The force of contraction will double. The contraction will be identical to that produced by the 1.0 volt.
The contraction will be of greater force, but not twice as great as occurred with the 1.0 V stimulus.
When a single stimulus is applied to a muscle, a curve of the tension developed (muscle twitch) can be generated. If the same strength stimulus is applied to the muscle again (after complete relaxation), how will the size of the second curve be altered? The height of the curve will be equal to that of the first curve. The height of the curve will be less than that of the first curve. The height of the curve will be greater than that of the first curve.
The height of the curve will be equal to that of the first curve.
Which of the following muscles is voluntary? The muscle in the wall of the urinary bladder The muscle that extends the arm at the elbow The muscle in the wall of the heart. The muscle of the stomach
The muscle that extends the arm at the elbow
Electrophysiology experiments established that a single motor neuron controlled more than 900 muscle cells. Predict where this muscle is located? Thigh Face Eye Hand
Thigh
hat regulatory molecule on the thin filament covers the myosin head binding site on actin? Troponin Tropomyosin
Tropomyosin
Which molecule on the thin filament has a binding site for calcium? Troponin Tropomyosin Actin
Troponin
A muscle twitch is a response to a single stimulus of adequate strength. True False
True
A sarcomere is a single contractile unit that extends from one Z line to the next. True False
True
A skeletal muscle is considered to be an organ because it contains more than one tissue type. True False
True
All muscles contain a mixture of Type I and Type II muscle fibers. True False
True
An oxygen binding protein in muscle cells, myoglobin, has a higher affinity (attraction) for oxygen than does oxygen binding protein in red blood cells, oxygen True False
True
Another name for Type II muscle fibers is fast-twitch fibers. True False
True
During aerobic respiration/glycolysis, glucose is converted into two ATP molecules. True False
True
Each muscle fiber must be stimulated by a motor neuron from the brain or spinal cord in order to function. True False
True
Each muscle uses the number of motor units necessary to move a load. True False
True
If all of the myosin heads detached at the same time the thin filament would slide backwards. True False
True
Once the motor end plate depolarizes, the action potential spreads from the local area in all directions and down the T-tubules. True False
True
The heavier the object, the more muscle units must be activated to move it. True False
True
The neuromuscular junction is the region of the muscle cell where a motor neuron stimulates the muscle cell to contract. True False
True
Two motor neurons can stimulate the contraction of two different groups of muscle cells within a single muscle to contract. True False
True
Type I muscle fibers primarily synthesize ATP aerobically True False
True
Type I muscle fibers vary from Type II muscle fibers in terms of their abilities to function aerobically True False
True
When ATP is hydrolyzed, the energy that is released is used for work such as moving myofilaments, transporting ions and changing protein confirmations True False
True
When ATP is hydrolyzed, the energy that is released is used for work such as moving myofilaments, transporting ions and changing protein confirmations. True False
True
if the first stimulus results in 9 grams of muscle tension, a second stimulus of the same strength will result in greater than 9 grams of tension. True F
True
Which type of muscle fiber has a large quantitiy of myoglobin and mainly uses aerobic respiration to synthesize ATP? Type I slow-twitch fibers Type II fast-twitch fibers
Type I slow-twitch fibers
What is the functional unit (the part that contracts) of a skeletal muscle called? a myofilament a sarcomere the sarcoplasmic reticulum a myofibril
a sarcomere
A graph of a muscle twitch (from a strip chart recorder) would have ____________________. a single peak. All answers are correct. the strength of contraction (tension) in grams plotted on the X-axis. the time in milliseconds plotted on the Y-axis.
a single peak.
Which of the following refers to a single muscle contraction treppe complete tetanus a twitch temporal summation
a twitch
The myosin head contains two binding sites, one site for ATP and one site for ____________________. actin. tropomyosin. troponin. calcium.
actin
During contraction ____________________. actin slides past myosin the thick and thin filaments do not overlap. the sarcomere lengthens. All answers are correct.
actin slides past myosin
Acetylcholine receptors are ____________________. located within voltage-gated ion channels. found in T-tubules and the motor end plate region. All answers are correct. associated with chemically gated ion channels.
associated with chemically gated ion channels.
An elongated muscle cell would ____________________. be under involuntary control contain one, centrally located nucleus be much smaller in diameter than the other two muscle cell types be found in a skeletal muscle
be found in a skeletal muscle.
If more than one motor unit in a single muscle is stimulated the resulting contraction will ____________________. be weaker. be stronger. fade quickly. be neutralized.
be stronger.
An action potential within the T-tubule results in the terminal cisternae of the sarcoplasmic retiuculum releasing ____________________. potassium. sodium. calcium. chloride.
calcium
A change in the conformation of the troponin-tropomyosin complex occurs when ____________________. the myosin head binds to actin. the action potential travels down the T-tubule. calcium is bound to troponin. ATP binds to the myosin head.
calcium is bound to troponin.
Which of the following is not a major muscle group of the human body? gluteus chest cardiac calves
cardiac
If a motor neuron is damaged permanently, the muscle cells it innervates will ____________________. spasm. experience an increase in tone. contract continuously. cease functioning and become flaccid.
cease functioning and become flaccid.
With rapid, multiple stimulations, the contractions fuse into a smooth, continuous contraction. This stage in the multiple stimuli graph is called: treppe. complete tetanus. incomplete tetanus. wave (temporal) summation.
complete tetanus.
Type I muscle fibers ____________________. are surrounded by few blood capillaries. are innervated by high frequency motor neurons tend to be larger than Type II muscle fibers. contain large quantities of the pigment molecule myoglobin.
contain large quantities of the pigment molecule myoglobin.
Type I muscle fibers ____________________. are surrounded by few blood capillaries. tend to be larger than Type II muscle fibers. are innervated by high frequency motor neurons contain large quantities of the pigment molecule myoglobin.
contain large quantities of the pigment molecule myoglobin.
The connective tissue covering individual muscle fibers/cells is called: epimysium perimysium endomysium
endomysium
The connective tissue covering of the whole muscle is called: epimysium perimysium endomysium
epimysium
_______ muscles causes the angle between two bones to increase. flexor extensor prime mover synergist
extensor
Whole muscle is composed of bundles of muscle cells called: fascicles myofibrils T tubules tendons
fascicles
skeletal muscle cell is also known as a ____________________. myomere. fiber. myofilament. myofibril.
fiber
_______ muscles causes the angle between two bones to decrease. flexor prime mover synergist extensor
flexor
An anaerobic metabolic pathway that results in the production of two net ATPs per glucose is ________. glycolysis hydrolysis the citric acid cycle the electron transport chain
glycolysis
An anaerobic metabolic pathway that results in the production of two net ATPs per glucose is ________. the electron transport chain the citric acid cycle hydrolysis glycolysis
glycolysis
The largest portion of a muscle is called the head/body origin insertion tendon
head/body
Myosin ____________________. is the major protein present in the thin filament. heads have the ability to move back and forth. plays no role in muscle cell contraction. is shaped like a baseball bat.
heads have the ability to move back and forth.
The main effect of the warm-up period of athletes, as the muscle contractions increase in strength, is to ________. increase the myoglobin content convert glycogen to glucose tone the muscles and stabilize the joints for the workout increase blood flow to the tissues
increase blood flow to the tissues
Which of the following is not a usual result of endurance training? increase in capillary density increase in cardiovascular health increase in the size of muscles (hypertrophy) increase in the myoglobin within the muscle cells
increase in the size of muscles (hypertrophy)
The movable end to which a muscle is attached is called origin head/body insertion tendon
insertion
The neuromuscular junction ____________________. All answers are correct. is formed when a motor nerve ending physically touches the motor end plate region of the sarcolemma. is the region where a motor neuron affects a muscle cell. is the space where the enzyme, acetylcholine, is released.
is the region where a motor neuron affects a muscle cell.
When acetylcholine diffuses away from its receptor ____________________. it is degraded when it is transported via the blood to the liver. it is directly transported back into the axon terminal for reuse later. it leaves the synaptic cleft and binds to receptors on other cells of the body. it is degraded by membrane bound acetylcholinesterase.
it is degraded by membrane bound acetylcholinesterase.
During vigorous exercise, there may be insufficient oxygen available to completely break it down to produce energy. As a result, the it leads to the production of a strong base stearic acid hydrochloric acid lactic acid
lactic acid
In the absence of oxygen, muscle metabolism produces ____________________. lactic acid. glycogen. creatine phosphate. ATP.
lactic acid.
Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the events of excitation-contraction coupling occur. contraction latent relaxation refractory
latent
he shortest phase of a muscle twitch, usually lasting less than 5 milliseconds, is called the: relaxation phase. latent period. contraction phase.
latent period.
In order for skeletal muscle cells to contract, they must be stimulated by a/an: sensory neuron. afferent neuron. motor neuron.
motor neuron.
Which of the following would be recruited later in muscle stimulation when contractile strength increases? many small motor units with the ability to stimulate other motor units large motor units with small, highly excitable neurons motor units with the longest muscle fibers motor units with larger, less excitable neurons
motor units with larger, less excitable neurons
The organelle that is a bundle of contractile elements is called a T tubule. muscle fiber. myofibril. terminal cisternae.
myofibril.
Muscle fibers are composed of several filaments called: myofibrils. fascicles. tendons. T tubules.
myofibrils
Oxygen is available for aerobic respiration directly from the blood and from stores in: glycogen. myoglobin. hemoglobin.
myoglobin
The oxygen-binding protein found in muscle cells is ________. immunoglobin hemoglobin myoglobin ATP
myoglobin
Rigor mortis occurs because ________. no ATP is available to release attached actin and myosin molecules proteins are beginning to break down, thus preventing a flow of calcium ions sodium ions leak out of the muscle the cells are dead
no ATP is available to release attached actin and myosin molecules
When a subthreshold stimulus is applied to a muscle ____________________. most muscle cells contract and a weak contraction occurs. few muscle cells contract, so there is no visible sign of contraction. no muscle cells contract, so contraction is not possible. all muscle cells contract and a visible contraction occur.
no muscle cells contract, so contraction is not possible.
According to the length tension relationship, 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 maximum force production would result because the muscle has a maximum range of travel no muscle tension could be generated
no muscle tension could be generated
The warm-up period and stretching done by athletes in order to bring their muscles to peak performance accomplishes all of the following except none of the choices increase flexibility increase blood flow to the muscle reduce the risk of injury
none of the choices
The immovable end to which a muscle is attached is called tendon head/body insertion origin
origin
The connective tissue covering the fasicles/muscle bundles is called: endomysium perimysium epimysium
perimysium
In a well trained endurance athlete, which of the following would you expect to find predominantly type II muscle fibers low capillary density predominantly Type I muscle fibers low levels of myoglobin in muscle fibers
predominantly Type I muscle fibers
In a well trained power athlete, which of the following would you expect to find high levels of myoglobin in the muscle fibers high mitochondrial density in the muscle fibers predominantly type II muscle fibers predominantly Type I muscle fibers
predominantly type II muscle fibers
_______ muscles produce most of the force in a muscle contraction. extensor flexor synergist prime mover
prime mover
Myoglobin ________. is a protein involved in the direct phosphorylation of ADP pulls in and stores oxygen in muscle cells breaks down glycogen produces the end plate potential
pulls in and stores oxygen in muscle cells
An increase in the strength of the stimulus will cause an increase in tension development caused by: recruitment of more motor units. an increased degree of muscle stretch. temporal summation.
recruitment of more motor units.
The major function of the sarcoplasmic reticulum in muscle contraction is to ________. make and store phosphocreatine provide a source of myosin for the contraction process regulate intracellular calcium concentration synthesize actin and myosin myofilaments
regulate intracellular calcium concentration
The muscle cell membrane is called the ________. endomysium epimysium perimysium sarcolemma
sarcolemma
What structure in skeletal muscle cells functions in calcium storage? sarcoplasmic reticulum mitochondria myofibrillar network intermediate filament network
sarcoplasmic reticulum
Which of the following is not a major muscle group of the human body triceps smooth biceps back
smooth
Creatine phosphate: is an intracellular oxygen binding molecule. is produced during glycolysis. is the enzyme that converts ADP + Pi to ATP. supplies typically are used up in seconds (e.g. during warm up).
supplies typically are used up in seconds (e.g. during warm up).
_______ muscles help to assist other muscle during a contraction. flexor prime mover synergist extensor
synergist
What controls the maximal force (tetanic contraction) of a single muscle fiber contraction? exceeding the threshold stimulus recruitment of multiple motor units concentric contractions temporal summation
temporal summation
What controls the maximal force (tetanic contraction) of a single muscle fiber contraction? temporal summation recruitment of multiple motor units exceeding the threshold stimulus concentric contractions
temporal summation
is/are connective tissue that connects muscle to bone cartilage tendons ligaments adipose tissue
tendons
The part of the sarcoplasmic reticulum where calcium ions are stored is called the: T tubules triad terminal cisternae
terminal cisternae
What produces the striations of a skeletal muscle cell? the arrangement of myofilaments the T tubules the sarcoplasmic reticulum a difference in the thickness of the sarcolemma
the arrangement of myofilaments
A muscle cell contracts when ____________________. the thin and thick filaments bind together. the thin filament slides past the thick filament. the thin filament shortens. the thick filament lengthens.
the thin filament slides past the thick filament.
Characteristics of type II muscle fibers include all of the following EXCEPT: the use of anaerobic respiration (glycolysis) to produce fast contractions. the use of aerobic respiration for primary ATP production. undergo hypertrophy the inability to undertake contractions necessary for endurance.
the use of aerobic respiration for primary ATP production.
There is/are _____ major type(s) of muscle. four two one three
three
During the initial phase of muscle contraction, each successive stimulus produces a slightly stronger contraction because of increased muscle warming and efficiency of enzymes. This stage is called: incomplete tetanus. complete tetanus. wave (temporal) summation. treppe.
treppe
In a resting state, ________________ covers the actin subunit binding site. troponin tropomyosin myosin ATP
tropomyosin
The development of tension in a muscle, in response to a single stimulus above threshold, is called a muscle ___________. contraction tetanus twitch
twitch
Temporal summation ____________________. will quickly lead to muscle fatigue. will not occur if the relaxation phase of the first contraction occurs. depicts fused, continuous peaks on a graph. is also know as treppe.
will not occur if the relaxation phase of the first contraction occurs.
A motor unit that contains only a few muscle cells per neuron ____________________. would result in strong contractions. would allow for precise movements. would allow for gross movements.
would allow for precise movements.
Match each phase of a muscle twitch to the activities that occur during that phase. Choices may be used more than once. Contraction (Period) Phase Latent (Period) Phase Relaxation (Period) Phase A. Myosin crossbridges cycle causing the sarcomere to shorten. Maximum muscle tension is reached. B. The sarcolemma and T-tubules depolarize. Calcium ions leave the sarcoplasmic reticulum and enter the cytosol. C. Calcium ions are actively transported back into the terminal cisternae of the sarcoplasmic reticulum.Cross bridge cycling ends.
Contraction (Period) Phase A. Myosin crossbridges cycle causing the sarcomere to shorten. Maximum muscle tension is reached. Latent (Period) Phase B. The sarcolemma and T-tubules depolarize. Calcium ions leave the sarcoplasmic reticulum and enter the cytosol. Relaxation (Period) Phase C. Calcium ions are actively transported back into the terminal cisternae of the sarcoplasmic reticulum.Cross bridge cycling ends.
The action potential causes the release of calcium ions from what structure in the muscle cell? Sarcolemma Cytosol Sarcoplasmic reticulum T tubule
Sarcoplasmic reticulum
Which type of muscle cell has visible striations and many nuclei and is under voluntary control? Skeletal Smooth Cardiac
Skeletal
Match each type of muscle cell to their physical characteristics. Skeletal muscle cell Smooth muscle cell Cardiac muscle cell A. Spindle-shaped, single centrally located nucleus, non-striated, and involuntary. B. Branching pattern, single centrally located nucleus, striated, and involuntary. C. Elongated, multiple peripherally located nuclei, striated and voluntary.
Skeletal muscle cell C. Elongated, multiple peripherally located nuclei, striated and voluntary. Smooth muscle cell A. Spindle-shaped, single centrally located nucleus, non-striated, and involuntary. Cardiac muscle cell B. Branching pattern, single centrally located nucleus, striated, and involuntary.