ch. 10/11 quiz
Predict what would happen to muscles if a pesticide that inhibits acetycholinesterase was present at the motor end plate. a. muscle would lose strength b. muscle would be unable to contract c. muscle would lock in a state of contraction d. muscle would contract repeatedly
????? (not b or d)
The A band is comprised of which of the following subunits? a. I-band, terminal cisternae, and the Z-line b. M line, H zone, and zone of overlap c. thin filaments, titin, and the z-line d. sarcoplasmic reticulum and t-tubules
M line, H zone, and zone of overlap
How is it possible for a skeletal muscle to contract without shortening? a. through eccentric contractions, the muscle lengthens b. through concentric contractions, the muscle does not change length c. through isometric contractions, the muscle remains the same length d. a and c are correct
a and c are correct
What would you expect to happen to a resting skeletal muscle if the sarcolemma suddenly become very permeable to Ca2+? a. increased strength of contraction b. decreased cross bridge formation c. decreased ability to relax d. both a and c
both a and c
Why does a muscle that has been overstretched produce less tension? a. few cross-bridges form, causing weak contraction b. cross-bridges cannot be formed c. actin and myosin cease to be stimulated by acetylcholine d. the increased amount of Ca2+ in the sarcoplasmic reticulum causes the muscle to relax completely
few cross-bridges form, causing weak contraction
The joint between the occipital bone of the skull and the first cervical vertebra (atlas) is part of which type of lever system? a. first-class lever system b. second-class lever system c. third-class lever system d. fulcrum/load/applied force lever system
first-class lever system
Where would you expect the greatest concentration of Ca2+ in resting skeletal muscle to be? a. in t-tubules b. surrounding the mitochondria c. within sarcomeres d. in cisternae of the sarcoplasmic reticulum
in cisternae of the sarcoplasmic reticulum
Which of the following is NOT a major function of skeletal muscle? a. maintaining body temperature b. lining hollow organs c. maintaining posture d. storing nutrients reserves
lining hollow organs
Why would you need a small motor unit to control movement of fingers? a. so it would not involve muscle fibers of adjoining fingers b. need precise control c. need twitches to cover a large area d. none of these are correct
need precise control
Myofibrils are organized into repeating units called ______. a. t-tubules b. z lines c. sarcomeres d. sarcoplasmic reticulum
sarcomeres
Which type of muscle fibers would you expect to predominate in the large leg muscles of someone who excels at endurance activities, such as cycling or long distance running. a. fast fibers b. slow fibers c. nonvascular fibers d. intermediate fibers
slow fibers
The benefit of third-class lever systems in muscles is? a. they operate at a mechanical advantage b. speed and distance traveled are increased c. the fulcrum lies between the applied force and the load d. none of these
speed and distance traveled are increased
