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Q:
Unipolar neurons have only a single process leading away from the soma.
Q:
Oligodendrocytes serve the same purpose in the CNS that satellite cells do in the PNS.
Q:
Ependymal cells line the inner cavities of the CNS.
Q:
In the brain, neurons are more abundant than neuroglia.
Q:
An action potential never occurs in dendrites.
TRUE Gradable: automatic 9. When a neuron is stimulated, Na+ gates open and allow Na+ to exit the cell.
FALSE Gradable: automatic
Q:
In a myelinated fiber, only the initial segment in the trigger zone has voltage-regulated channels.
Q:
Where would you expect to find numerous gap junctions in muscular tissue?
A. The sarcoplasmic reticulum of skeletal muscle
B. The A bands of skeletal and cardiac muscle
C. The sarcolemma of skeletal muscle
D. The intercalated discs of cardiac muscle
E. Multiunit smooth muscle
Q:
Why is the contraction strength of smooth muscle relatively independent of its resting length?
A. It gets nearly all of its Ca2+ from the extracellular fluid.
B. It does not have intercalated discs.
C. It does not have sarcomeres.
D. It is regulated by a length-tension relationship.
E. It is involuntary muscle.
Q:
An isometric contraction does not change muscle length.
Q:
Some smooth muscle is autorhythmic.
Q:
Which of the following marks the boundaries of a sarcomere?
A. I bands
B. H bands
C. Z discs
D. M lines
E. A bands
Q:
Which of the following is predominately made up of myosin?
A. G actin
B. F actin
C. The thin filament
D. The thick filament
E. The elastic filament
Q:
Which of the following contains overlapping thick and thin filaments?
A. A band
B. H band
C. I band
D. M line
E. Z discs
Q:
Which of the following is not a purpose of the excess postexercise oxygen consumption (EPOC) in muscle?
A. To neutralize carbon dioxide buildup
B. To replenish the phosphagen system
C. To oxidize lactic acid
D. To serve elevated metabolic rate
E. To restore resting levels of ATP and CP
Q:
Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source?
A. Skeletal muscle
B. Smooth muscle
C. Cardiac muscle
D. Skeletal and smooth muscle
E. Smooth and cardiac muscle
Q:
Which muscle(s) can contract without the need for nervous stimulation?
A. Skeletal muscle only
B. Smooth muscle only
C. Cardiac muscle only
D. Smooth and cardiac muscle
E. Skeletal, smooth and cardiac muscle
Q:
80% of the lactic acid produced by skeletal muscle is converted to pyruvic acid by the __________.
A. kidneys
B. liver
C. muscle tissue
D. sarcoplasmic reticulum
E. neuromuscular junction
Q:
During muscle contraction, a single myosin head consumes ATP at a rate of about __________ ATP per second.
A. 1
B. 3
C. 5
D. 7
E. 9
Q:
Shortening a muscle while it maintains constant tension is called __________.
A. complete tetanus
B. incomplete tetanus
C. an isokinetic contraction
D. an isometric contraction
E. an isotonic contraction
Q:
Which fibers are primarily responsible for producing lactic acid?
A. Type I slow oxidative fibers
B. Type IIA intermediate glycolytic fibers
C. Type IIB fast glycolytic fibers
D. Type I slow-twitch fibers
E. Red fibers
Q:
Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed __________ fibers.
A. red
B. white
C. intermediate
D. fast twitch
E. slow oxidative
Q:
Clinically, dystrophin is the most important noncontractile protein to occur in muscle fibers.
Q:
The sliding filament theory of muscle contraction has emerged from research only in the last 10 to 15 years.
Q:
A deficiency of acetylcholine receptors leads to muscle paralysis in myasthenia gravis.
Q:
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?
A. They have smaller mitochondria.
B. They have more glycogen in them.
C. They don't have as many blood capillaries per gram of tissue.
D. They make more use of aerobic respiration.
E. They break ATP down to ADP and Pi faster.
Q:
Why does one continue to breathe heavy after rigorous physical activity has stopped?
A. The diaphragm is waiting for its acetylcholine to run out.
B. The body requires more oxygen to restore levels of ATP and creatine phosphate.
C. The lungs can't stop breathing until the heart rate slows down.
D. Myosin heads need more oxygen to fully detach from actin.
E. The kidneys require oxygen to dispose of excess lactic acid.
Q:
In skeletal muscle, the term that describes the alternating light and dark bands is ___________.
A. strabismus
B. striations
C. tetanus
D. myofibrils
E. myoblasts
Q:
The training regimen of a competitive weight lifter is designed partly to __________.
A. convert certain parallel muscles into stronger pennate muscles
B. increase the average number of myofibrils per muscle fiber
C. convert white muscle tissue to red muscle
D. increase the size of his motor units
E. lower the threshold for muscle excitation
Q:
All muscle types will respond to an electrical stimulus because all muscle cells are _________.
A. excitable
B. contractile
C. striated
D. involuntary
E. isometric
Q:
Skeletal muscle is called ___________, because it is usually subject to conscious control.
A. excitable
B. contractile
C. striated
D. voluntary
E. isometric
Q:
When a skeletal muscle lengthens, its __________ helps resist excessive stretching and subsequent injury to the muscle.
A. thick filaments
B. collagen
C. actin
D. troponin-tropomyosin complex
E. varicosities
Q:
Extensibility refers to the ability of a muscle to stretch.
Q:
A dark band formed by parallel thick filaments that partly overlap the thin filaments is known as an H band.
Q:
The sarcoplasmic reticulum is the smooth endoplasmic reticulum of a muscle fiber.
Q:
Which of the following is not a characteristic of a muscle cell?
A. Plasticity
B. Contractility
C. Conductivity
D. Extensibility
E. Excitability
Q:
Which of the following is a property of collagen?
A. Contractility
B. Excitability
C. Elasticity
D. Expendability
E. Impermeability
Q:
A myofilament that runs throught the core of a thick filament and anchors it to a Z disc is called a(n) __________.
A. myofibril
B. thin filament
C. T tubule
D. sarcolemma
E. elastic filament
Q:
The synaptic knob releases acetylcholine into the synaptic cleft, which is received by receptors on the motor end plate. Which structure does this describe?
A. A sarcomere
B. The thick filament
C. The varicosity of a smooth muscle cell
D. The neuromuscular junction of a skeletal muscle
E. A motor unit
Q:
A skeletal muscle generates the greatest tension when it is __________.
A. greatly stretched before being stimulated
B. partially stretched before being stimulated
C. fully relaxed before being stimulated
D. well-rested and low in creatine phosphate
E. high in lactic acid concentration
Q:
When acetylcholinesterase outlasts the release of acetylcholine from the synaptic vesicles, the skeletal muscle __________.
A. contracts
B. gets stronger
C. relaxes
D. releases Ca++
E. opens its Na+ channels
Q:
The transfer of phosphate from CP to ADP is catalyzed by __________.
A. myokinase
B. creatinine
C. cAMP
D. creatine kinase
E. ATP
Q:
What happens when acetylcholine stimulates its receptors in the neuromuscular junction?
A. The release of Ca2+ from the sarcoplasmic reticulum decreases.
B. The permeability of the sarcolemma to Na+ increases.
C. The positive charge on the sarcolemma decreases.
D. The threshold of the muscle fiber lowers.
E. The inhibitory effect of acetylcholinesterase is overridden.
Q:
Which of the following best describes the resting membrane potential (RMP)?
A. The intracellular environment is negatively charged.
B. The intracellular environment has more positively charged sodium.
C. The extracellular environment is negatively charged.
D. It has a voltage of about +75 mV.
E. It is dependent upon the absorption of potassium ions by the muscle fiber.
Q:
The sarcolemma of a resting muscle fiber is most permeable to __________.
A. calcium
B. potassium
C. sodium
D. lithium
E. magnesium
Q:
What is the purpose of the triad?
A. The triad stores sodium.
B. The triad synthesizes ATP.
C. The triad maintains the resting membrane potential.
D. The triad removes acetylcholine from the synaptic cleft.
E. The triad allows for Ca2+ release when a muscle fiber is excited.
Q:
Which of the following individuals would have more mitochondria in her skeletal muscle?
A. A 50-year-old sedentary computer programmer
B. A 22-year-old soccer player
C. A long-term hospice patient
D. A model on a reduced-calorie diet
E. A newborn
Q:
Which of the following systems would provide energy for a racquetball player, while playing a point?
A. The respiratory system
B. The glycolysis system
C. The phosphagen system
D. The anaerobic system
E. The glycogen-lactic acid system
Q:
Loss of muscle mass from lack of activity is called __________.
A. myopathy
B. dystrophy
C. apathy
D. atrophy
E. tetanus
Q:
Which of the following would be caused by a contraction of smooth muscle?
A. Goose bumps
B. Blood leaving the left ventricle of the heart
C. Elevating the eyebrows
D. Blinking the eyelids
E. Deep inspiration
Q:
The triads of a muscle fiber consist of __________.
A. two A bands and one I band
B. two T tubules and one terminal cisterna
C. two terminal cisternae and one T tubule
D. two thin myofilaments and one thick myofilament
E. two thick myofilaments and one thin myofilament
Q:
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 __________.
A. recruit more muscle fibers
B. lower its threshold
C. reduce its wave summation
D. shift from isometric to isotonic contraction
E. shift from slow-twitch to fast-twitch mode
Q:
The protein that acts as a calcium receptor in skeletal muscle is __________.
A. F actin
B. tropomyosin
C. troponin
D. titin
E. dystrophin
Q:
Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. How do you suppose these drugs work?
A. They prevent calcium from entering the sarcoplasmic reticulum of smooth muscle.
B. They stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin.
C. They prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle.
D. They prevent calcium from entering cardiac muscle, thus slowing down the heart rate.
E. They prevent calcium from entering smooth muscle, thus allowing the muscle to relax.
Q:
Exposure to the bacterium Clostridium tetani causes continuous release of acetylcholine. What effect does this have on smooth muscle?
A. Flaccid paralysis
B. Spastic paralysis
C. Lockjaw
D. No effect
E. Myocardial atrophy
Q:
Where is dystrophin, the protein that is defective in muscular dystrophy, normally found?
A. Between the outermost myofilaments and the sarcolemma of a muscle fiber
B. As a transmembrane protein of the sarcolemma
C. In the Z discs of skeletal and cardiac muscle
D. In the dense bodies of smooth muscle
E. Bridging the gap between the sarcolemma and synaptic knob
Q:
Which of the following has the largest mitochondria?
A. Slow oxidative fibers
B. Fast glycolytic fibers
C. Cardiac muscle
D. Smooth muscle
E. Intermediate fibers
Q:
What is the purpose of motor nerve varicosities as they relate to smooth muscle?
A. They link the thin filaments to the inside of the sarcolemma in smooth muscle.
B. They reabsorb the decomposition products of acetylcholine after acetylcholinesterase breaks it down.
C. They enable each cardiac myocyte to directly stimulate its neighbors.
D. They release neurotransmitter onto smooth muscle cells.
E. They prevent single-unit smooth muscle cells from pulling apart.
Q:
How many muscle fibers stimulate one somatic motor neuron?
A. 0
B. 1
C. 2
D. 3
E. 4
Q:
To stimulate muscle contraction, acetylcholine is released from the ___________ into the synaptic cleft.
A. synaptic vesicles
B. junctional folds
C. sarcoplasmic reticulum
D. sarcolemma
E. terminal cisterna
Q:
The absence or inhibition of acetylcholinesterase at a synapse would lead to __________.
A. flaccid paralysis
B. tetanus
C. atrophy
D. numbness
E. muscle wasting
Q:
Which statement best describes the goal of medications used to treat myasthenia gravis?
A. To increase the number of acetylcholine receptors
B. To decrease the number of synaptic vesicles
C. To promote multiple motor unit summation
D. To inhibit Ca2+ release from the sarcoplasmic reticulum
E. To inhibit the function of cholinesterase
Q:
The process of engaging more motor units to increase the strength of a muscle contraction is called __________.
A. wave summation
B. recruitment
C. temporal summation
D. incomplete tetanus
E. complete tetanus
Q:
Aerobic respiration produces approximately _________ more ATPs per glucose molecule than glycolysis does.
A. 12
B. 24
C. 36
D. 48
E. 100
Q:
Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in __________.
A. increased glycolysis
B. increased use of myokinase
C. longer aerobic respiration
D. longer anaerobic fermentation
E. reduced ATP consumption
Q:
Cardiac muscle has very little capacity for regeneration because it lacks __________.
A. satellite cells
B. an endomysium
C. sarcomeres
D. dense bodies
E. somatic nerve fibers
Q:
After childbirth, a woman begins experiencing tremendous pain in her groin, making it difficult for her to walk. An X-ray shows a fracture extending from her symphysis pubis to the inferior ramus of the pubis. As a result of the fracture, which group of muscles might be impaired?
A. Hip flexors
B. Thigh abductors
C. Hip extensors
D. Lateral rotators
E. Thigh adductors
Q:
A skydiver's parachute fails to deploy. After some struggle, his reserve chute deploys in time to save his life. However, his landing is harder than normal and he feels his knee slightly hyperextend. He shakes it off and goes about his normal routine. Later that day he begins experiencing knee pain. Two days later he notices that his knee "pops" when he crouches and soon discovers he has dislocated his femur on the knee. What muscle was likely injured initially?
A. Popliteus
B. Tensor fasciae latae
C. Soleus
D. Sartorius
E. Quadriceps femoris
Q:
A skateboarder falls and lands directly on his buttocks and lower back. He does not feel much pain and continues skating. After a couple of days he begins experiencing right hip pain and notices his right foot and leg are rotated to the right. A doctor diagnoses a muscle spasm. Which of the following muscles is most likely causing the leg and foot rotation?
A. Quadratus lumborum
B. Tibialis posterior
C. Piriformis
D. Adductor longus
E. Sacrospinalis
Q:
When you kick a soccer ball, you contract your quadriceps femoris. Because the attachment on the tibia moves towards the attachment on the femur, it is considered the __________.
A. insertion
B. origin
C. belly
D. innervation
Q:
Based on what you know about muscle attachments, which of the following is true?
A. An insertion generally moves towards an origin in contraction.
B. An origin generally moves towards an insertion in contraction.
C. An insertion generally moves towards another insertion in contraction.
D. An origin generally moves towards another origin in contraction.
Q:
An __________ muscle is contained within a region whereas an __________ muscle acts upon one region but has an origin elsewhere.
A. intrinsic; extrinsic
B. extrinsic; intrinsic
C. innate; extraneous
D. extraneous; innate
Q:
You hear a loud noise behind you and look back over your left shoulder. Which of the following is true?
A. This was a contralateral contraction of your right sternocleidomastoid muscle.
B. This was a contralateral contraction of your left sternocleidomastoid muscle.
C. This was an ipsilateral contraction of your right sternocleidomastoid muscle.
D. This was an ipsilateral contraction of your left sternocleidomastoid muscle.
Q:
A clinician induces contraction of the gastrocnemius and soleus and notices that the foot does not plantar flex as expected. Which of the following would be a logical diagnosis?
A. Peroneal nerve injury
B. Ruptured calcaneal tendon
C. Anterior compartment syndrome
D. Shinsplints
E. Lateral plantar nerve injury
Q:
A male sustains a crushing injury to his foot. After weeks of care, he begins to notice that he cannot bend the little toe on his right foot. Which of he following would be a logical diagnosis? A. Atrophy of the flexor hallucis brevis
B. Atrophy of the fibularis brevis
C. Atrophy of the soleus
D. Atrophy of the flexor digiti minimi
E. Atrophy of the adductor hallucis
Q:
A heavyset middle-aged insurance salesman, who doesn't exercise often, accepts his friend's invitation to a pickup basketball game. When attempting a jump shot, he falls to the ground in pain, grasping at the calf of his leg. There is an enormous bulge in his leg immediately below the popliteal fossa, and he is unable to plantar flex that foot. Most likely he has injured his __________ and the bulge is __________.
A. quadriceps tendon; his rectus femoris
B. calcaneal tendon; his triceps surae
C. patellar ligament; his fibularis longus
D. tibia; a previously undetected bone tumor
E. hamstrings; a large hematoma (blood clot)
Q:
An Olympic sprinter readies for a race. After the sound of the starting gun, he propels himself forward from the starting block and immediately grimaces in pain, grabbing for the back of his thigh. Within 48 hours he begins noticing extensive bruising on the back of his thigh extending into the back of the knee. He now has difficulty rising from a seated position and flexing his knee. Bending at the waist generates more pain. Which muscle is likely injured?
A. Gluteus maximus
B. Popliteus
C. Biceps femoris
D. Gastrocnemius
E. Iliopsoas
Q:
Tennis elbow is a common term describing injury to the origin of which of the following?
A. Extensor hallucis longus
B. Pronator quadratus
C. Extensor carpi radialis longus
D. Subscapularis
E. Flexor digitorum profundus
Q:
An injury that results in complete functional loss of the ulnar nerve will affect which of the following muscles?
A. Abductor digiti minimi
B. Abductor pollicis brevis
C. Flexor carpi radialis
D. Brachioradialis
E. Extensor indicis
Q:
Carpal tunnel pressure is sometimes relieved by surgically excising part or all of which structure?
A. Palmar aponeurosis
B. Extensor retinaculum
C. Flexor retinaculum
D. Extensor aponeurosis
E. Median nerve
Q:
What is the longest muscle in the human body?
A. Iliopsoas
B. Sartorius
C. Erector spinae
D. Semitendinosus
E. Semimembranosus