Skeletal
Muscle
Anatomy
Muscle
Anatomy
What is the functional unit of a skeletal muscle is termed?
a. sarcomere
b. A band
c. myofibril
d. sarcolemma
a. sarcomere
When a muscle cell is at rest, most of the intracellular calcium is found stored in the _________.
a. sarcoplasm
b. T tubule
c. sarcoplasmic reticulum
d. myosin heads
c. sarcoplasmic reticulum
A single contraction in response to a single threshold stimulus is defined as _________.
a. summation
b. tetany
c. treppe
d. a twitch
d. a twitch
The energy source that is used directly for muscle contraction is ______.
a. ATP
b. glucose
c. creatine phosphate
d. fatty acids
a. ATP
Contraction of which sheet of smooth muscle results in dilation?
a. Circular layer
b. Transverse layer
c. Longitudinal layer
d. Square layer
c. Longitudinal layer
A sheetlike extension of the epimysium is called a(n) ______.
a. aponeurosis
b. fascicle
c. sarcoplasmic reticulum
d. tendon
a. aponeurosis
Calcium ions in the sarcoplasm will bind to ________.
a. myosin heads
b. ATP
c. myosin-binding sites
d. troponin
d. troponin
The force exerted by a contracting muscle is _______.
a. muscle summation
b. muscle twitch
c. muscle tension
d. muscle load
c. muscle tension
Muscle soreness may be due in part to which pathway of ATP production?
a. Phosphorylation
b. Aerobic respiration
c. Anaerobic glycolysis
d. Oxidation
c. Anaerobic glycolysis
Smooth muscle cells can contract as a unit due to the presence of ______.
a. dense bodies
b. gap junctions
c. diffuse junctions
d. motor end plates
b. gap junctions
Thick filaments are found in the _______ of the sarcomere.
a. Z disc
b. I band
c. A band
d. All of the above contain thick filaments.
c. A band
What substance must bind to myosin heads in order for the heads to detach from the thin filaments?
a. Calcium
b. ATP
c. Troponin
d. Sodium
b. ATP
The time that elapses between the stimulation of a muscle and the contraction of that muscle is defined as the ______.
a. depolarization period
b. latent period
c. recruitment period
d. refractory period
b. latent period
After about 30 minutes of exercise, which substance becomes the major source of fuel?
Glucose
Pyruvic acid
Fatty acid
Lactic acid
d. Poor blood supply
Fatty acid
Calcium binds to this substance in smooth muscle contraction.
a. Troponin
b. Calmodulin
c. ATP
d. Myosin kinase
b. Calmodulin
In a resting muscle cell, the myosin-binding sites are blocked by ______.
a. actin
b. troponin
c. titin
d. tropomyosin
d. tropomyosin
Calcium is released from the terminal cisterns in response to ______.
a. ATP
b. calcium pumps
c. an action potential
d. troponin
c. an action potential
Which is not a factor that affects the force of muscle contraction?
a. Relative size of muscle fibers
b. Number of muscle fibers stimulated
c. Degree of muscle stretch
d. Method of muscle stimulation
d. Method of muscle stimulation
Which activity would be most dependent upon creatine?
Tennis
Soccer
Jogging
Diving
Diving
Smooth muscle contains ______ that correspond to the Z discs of skeletal muscle.
a. dense bodies
b. varicosities
c. diffuse junctions
d. gap junctions
a. dense bodies
T tubules are an extension of the _________.
a. sarcomere
b. sarcoplasmic reticulum
c. sarcolemma
d. endomysium
c. sarcolemma
How does calcium reenter the terminal cisterns after muscle contraction is finished?
a. Diffusion
b. Active transport
c. Filtration
d. Endocytosis
b. Active transport
Skeletal muscle contractions increase in strength due to ______.
a. incomplete tetany
b. recruitment of motor units
c. an increase in threshold stimulus
d. increasing the number of twitches
b. recruitment of motor units
______ is the length of time a muscle can continue to contract using aerobic pathways.
a. Aerobic threshold
b. Anaerobic threshold
c. Aerobic endurance
d. Anaerobic endurance
c. Aerobic endurance
What unique characteristic of smooth muscle allows your stomach to stretch as you eat and not contract immediately to expel food?
a. Hyperplasia
b. Slow contraction
c. Single unit contraction
d. Stress-relaxation response
d. Stress-relaxation response