Q&A Hero

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 is not a characteristic of a muscle cell? A. Plasticity B. Contractility C. Conductivity D. Extensibility E. Excitability

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: 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: 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: 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: 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

Q: Which of the following muscles is in the medial compartment of the thigh? A. Soleus B. Adductor longus C. Piriformis D. Vastus medialis E. Semimembranosus

Q: Which of the following muscles inserts on the head of the fibula? A. Extensor digitorum longus B. Tibialis anterior C. Popliteus D. Biceps femoris E. Semitendinosus

Q: Which muscle is innervated by the tibial nerve? A. Extensor digitorum longus B. Tibialis anterior C. Semimembranosus D. Fibularis longus E. Vastus lateralis

Q: Which of the following muscles is responsible for medially rotating the tibia on the femur when the knee is flexed? A. Piriformis B. Semitendinosus C. Adductor brevis D. Vastus medialis E. Sartorius

Q: Which of the following muscles adducts and medially rotates the thigh? A. Gracilis B. Piriformis C. Adductor magnus D. Rectus femoris E. Sartorius

Q: Which of the following muscles is innervated by the obturator nerve? A. Gracilis B. Biceps femoris C. Tibialis anterior D. Soleus E. Sartorius

Q: Injury to the deep fibular nerve would cause inability to extend ones toes.

Q: The triceps surae consists of three muscles in the lower limb.

Q: The antagonist to the triceps brachii is the __________. A. deltoid B. anconeus C. biceps brachii D. supinator E. teres minor

Q: Which of the following best describes the insertion of the extensor digitorum? A. It indirectly inserts on all digits of the hand. B. It indirectly inserts on all digits of the hand except the thumb. C. It directly inserts on all digits of the hand. D. It directly inserts on all digits of the hand except the thumb. E. It directly inserts on the index finger only.

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: Which cranial nerve innervates the sternocleidomastoid and trapezius? A. Abducens B. Facial C. Vagus D. Accessory E. Trigeminal

Q: Which muscle(s) of respiration is(are) innervated by the phrenic nerve? A. Diaphragm B. External intercostals C. Internal intercostals D. Innermost intercostals E. Pectoralis major

Q: After taking their wedding vows, a bride and groom often ceremonially use which of the following muscles before walking away from the altar? A. Depressor anguli oris B. Orbicularis oris C. Levator labii superioris D. Platysma E. Quadriceps femoris

Q: Which muscle originates at the manubrium, inserts on the thyroid cartilage, and aids in singing low notes? A. Omohyoid B. Thyrohyoid C. Sternothyroid D. Stylohyoid E. Lateral pterygoid

Q: Some people suffer involuntary urination due to incompetence of what muscle? A. External urethral sphincter B. Bulbospongiosus C. Compressor urethrae D. Ischiocavernosus E. Levator ani

Q: A sacral fracture affecting the S3 and S4 nerve roots would result in a person having difficulty with evacuation of the bowels.

Q: A baseball pitcher who injures one of his SITS muscles most commonly sustains tears to the tendon of which muscle? A. Supraspinatus B. Infraspinatus C. Teres minor D. Subscapularis E. Deltoid

Q: Which of the following is true regarding the levator scapulae? A. It is innervated by the phrenic nerve. B. It elevates the scapula if the scapula is fixed. C. It rotates the scapula and depresses the apex of the shoulder. D. It flexes the neck if the scapula is fixed. E. It protracts the scapula if the humerus is fixed.

Q: Which of the following is an intrinsic muscle of the hand? A. Extensor carpi radialis brevis B. Adductor pollicis C. Extensor pollicis longus D. Extensor indicis E. Abductor pollicis longus

Q: The serratus anterior is innervated by which nerve? A. Accessory B. Dorsal scapular C. Long thoracic D. Lateral pectoral E. Axillary

Q: Which muscle acting on the arm assists in deep inspiration? A. Pectoralis major B. Trapezius C. Teres minor D. Diaphragm E. Deltoid

Q: A butcher who cuts the distal portion of his fingers may cut the __________ tendon. A. flexor pollicis longus B. flexor carpi ulnaris C. palmaris longus D. adductor pollicis E. flexor digitorum profundus

Q: When a nurse draws blood, it is not uncommon for the needle to penetrate which muscle near the cubital region? A. Pronator quadratus B. Semimembranosus C. Pronator teres D. Buccinator E. Supinator

Q: The muscles that laterally rotate and depress the scapula, as in shrugging and lowering the shoulders, are the __________. A. trapezius and serratus anterior B. pectoralis minor and serratus anterior C. levator scapulae and rhomboideus D. trapezius and rhomboideus E. trapezius and latissimus dorsi

Q: A point of convergence for several muscles of the lower face is the __________. A. retinaculum B. aponeurotica C. modiolus D. nuchal line E. galea

Q: The ________ originates on the zygomatic arch and inserts on the angle of the mandible. A. masseter B. buccinator C. temporalis D. genioglossus E. stylohyoid

Q: Which one of these muscles helps to open the mouth (depress the mandible)? A. Zygomaticus major B. Digastric C. Sternohyoid D. Depressor anguli oris E. Hyoglossus

Q: The palatoglossus is innervated by which nerve(s)? A. Hypoglossal B. Accessory C. Vagus D. Hypoglossal and accessory E. Accessory and vagal

Q: Which of the following muscles of mastication would be responsible for mandibular elevation? A. Temporalis B. Lateral pterygoid C. Stylohyoid D. Zygomaticus major E. Zygomaticus minor

Q: The aponeurosis of the external oblique forms the ________ at its inferior margin. A. linea alba B. rectus sheath C. linea semilunaris D. medial retinaculum E. inguinal ligament

Q: The deepest muscle of the abdominal wall is the __________. A. transverse abdominal B. internal oblique C. rectus abdominis D. latissimus dorsi E. pectoralis minor

Q: While sitting at your desk, you drop your pencil onto the floor. You bend over to pick up the pencil. In order to straighten up and continue your exam you must use which of the following muscles? A. Tibialis anterior B. Erector spinae C. Semimembranosus D. Tibialis anterior and semimembranosus E. Extensor hallucis longus

Q: Which of the following muscles is not externally visible on the trunk of the body? A. Transverse abdominal B. Latissimus dorsi C. Trapezius D. Pectoralis major E. External abdominal oblique

Q: Unilateral contraction of which muscle causes ipsilateral flexion of the lumbar vertebral column? A. Multifidus B. Latissimus dorsi C. External intercostals D. Serratus anterior E. Quadratus lumborum

Q: In lifting a heavy weight from the floor, one should use the power of the __________ in order to avoid straining the lower back. A. biceps brachii and brachialis B. gastrocnemius and soleus C. external and internal abdominal obliques D. knee and hip extensors E. trapezius and latissimus dorsi

Q: In a whiplash injury, the neck undergoes forced hyperextension then hyperflexion, injuring multiple muscles in the neck. Which of the following muscles would be injured during the hyperextension phase of the injury? A. Trapezius B. Splenius capitis C. Sternocleidomastoid D. Semispinalis capitis E. Levator scapulae

Q: Tendinous intersections divide the __________ into segments that are externally visible on the abdomen of a well-muscled person. A. vastus lateralis B. serratus anterior C. rectus abdominis D. quadriceps femoris E. transverse abdominal

Q: The rectus abdominis is a __________ muscle, while the rectus femoris is a __________ muscle. A. fusiform; parallel B. parallel; bipennate C. convergent; unipennate D. bipennate; parallel E. multipennate; convergent