module 6 Flashcards
The more movable bony attachment is the ___
a. flexor
b. origin
c. extensor
d. insertion
d. insertion
Muscles which move a limb away the midline of the body are ___ muscles.
a. abductor
b. adductor
c. extensor
d. flexor
a. abductor
A muscle that constricts an opening is a/an
a. extensor
b. levator
c. antagonist
d. sphincter
d. sphincter
The prime mover of any skeletal movement is called the___
a. flexor
b. agonist
c. abductor
d. antagonist
b. agonist
The biceps brachia causes flexion of the elbow. The triceps brachii causes extension of the elbow, so it is a/an___
a. abductor
b. antagonist
c. agonist
d. levator
b. antagonist
Each fascicle of a muscle is surrounded by ___
a. perimysium
b. epimysium
c. endomysium
d. sarcolemma
a. perimysium
The light band of a skeletal muscle is known as the ___
a. A band
b. Z disc
c. I band
d. H band
c. I band
The specialized region of the sarcolemma at the neuromuscular junction is called the___
a. syncytium
b. varicosity
c. fascicle
d. motor end plate
d. motor end plate
Somatic motor neurons release the neurotransmitter ___ at the neuromuscular junction.
a. dopamine
b. acetylcholine
c. norepinephrine
d. serotonin
b. acetylcholine
Each somatic motor neuron with all the muscle fibers it innervates is a
a. fascicle
b. varicosity
c. motor unit
d. sarcolemma
c. motor unit
Subunits of skeletal muscle fibers that are composed of sarcomeres are called ___
a. myofibrils
b. myofilaments
c. sarcolemmas
d. transverse tubules
a. myofibrils
What is the structural and functional unit of skeletal muscle?
a. A band
b. I band
c. Sarcomere
d. Myofibril
c. Sarcomere
The A band is composed primarily of ___
a. thick filaments
b. thin filaments
c. actin
d. titin
a. thick filaments
What protein primarily makes up the thick filaments?
a. Actin
b. Myosin
c. Titin
d. Troponin
b. Myosin
Myosin contains binding sites for ___ and ___.
a. sodium; calcium
b. troponin; ATP
c. ATP; actin
d. actin; calcium
c. ATP; actin
During skeletal muscle contraction, ____.
a. the H band increases in size
b. Ca +2 associates with tropomyosin
c. myosin heads interact with tropomyosin
d. thin filaments slide across thick filaments
d. thin filaments slide across thick filaments
Which of the following molecules is NOT part of the thin filaments?
a. Actin
b. Titin
c. Troponin
d. Tropomyosin
b. Titin
Which molecule blocks the myosin head from binding to actin in a relaxed muscle?
a. Tropomyosin
b. Troponin
c. Calcium
d. Titin
a. Tropomyosin
Choose the description of an event that does NOT occur during the cross bridge cycle.
a. A new ATP binding causes cross bridges to release
b. ADP is released at the end of there power stroke
c. Energized myosin heads bind troponin
d. ATP hydrolysis allows for cross bridge formation
c. Energized myosin heads bind troponin
The movement of the troponin-tropomyosin complex requires ___
a. ATP
b. Ca 2+
c. acetylcholine
d. Na +
c. Ca 2+
The Ca 2+ required for skeletal muscle contraction ___
a. is released from the sarcoplasmic reticulum
b. enters the cell due to the opening of voltage regulated Ca 2+ channels from the T tubules
c. is actively transported into the cell
d. is released from mitochondria
a. is released from the sarcoplasmic reticulum
The pumps that actively transport calcium back into the ___ are called Ca +2 -ATPase pumps.
a. transverse tubules
b. sarcoplasmic reticulum
c. neuromuscular junction
d. none of the choices are correct
b. sarcoplasmic reticulum
What structures carry the action potentials into the interior of the muscle to cause muscle contraction?
a. T tubules
b. Terminal cisternae
c. Sarcoplasmic reticula
d. Ryanodine receptors
a. T tubules
Which of the following is NOT true of the relaxation of a muscle fiber?
a. ATP is needed to fuel the calcium pumps
b. calcium release channels in the sarcoplasmic reticulum close
c. calcium moves from troponin to tropomyosin
d. Ca 2+ moves from the sarcoplasm to the sarcoplasmic reticulum
c. Calcium moves from troponin to tropomyosin
The inability of muscle cells to relax due to high frequency stimulation is called ___
a. treppe
b. recruitment
c. twitch
d. tetanus
d. tetanus
The staircase effect or ___ represents a warm up effect due to increasing intracellular calcium concentrations.
a. treppe
b. tetanus
c. incomplete tetanus
d. tonus
a. treppe
A muscle contraction against a resistance greater than the force of contraction causes muscle lengthening is called a(n)____ contraction
a. concentric
b. isometric
c. eccentric
d. isokinetic
c. eccentric
Slow twitch fibers have a ___ oxidative capacity and ___ glycogen content.
a. high; high
b. high; low
c. low; low
d. low; high
b. high; low
Muscle fatigue occurs ___
a. when muscles are only partially able to contract
b. when muscle cell glycogen is depleted
c. when muscle cell pH increases
d. due to decreased extracellular K+
b. when muscle cell glycogen is depleted
Muscle hypertrophy is due to __
a. increased number of myofibrils in the muscle fiber
b. increased number of muscle fibers
c. increased size of the myofibrils
d. both increased number of myofibrils in the muscle fiber and increased size of the myofibrils
d. both increased number of myofibrils in the muscle fiber and increased size of the myofibrils
___ is characterized by continued attachment of myosin heads to actin filaments due to a lack of ATP.
a. Tetanus
b. Rigor mortis
c. Flaccid paralysis
d. Treppe
b. Rigor mortis
What is the role of ATP in muscle contraction and relaxation?
a. it is hydrolyzed by the myosin head prior to cross bridge formation
b. it causes myosin head to detach from actin after the powerstroke
c. it powers the Ca 2+ pumps to return Ca 2+ to the SR
d. all apply
d. all apply