Biol 246 KU exam 3 questions well
answered 2025/2026
How does a nerve connect to a muscle fiber in vertebrae skeletal muscle? - correct answer
✔✔Each muscle fiber is connected to one motor neuron only at one spot.
Motor Unit - correct answer ✔✔all muscle fibers connected to one motor axon
How do motor units contract? - correct answer ✔✔all-or-none
How doe muscles create contractions of different forces and duration? - correct answer
✔✔Recruitment of different types/numbers of motor units
Weak stimuli - correct answer ✔✔activates neurons with low thresholds
Strong stimuli - correct answer ✔✔activates neurons with higher thresholds
The ____ motor units recruited, the ____ the force generated - correct answer ✔✔more,
greater
Fine control - correct answer ✔✔1:1, neuron to fiber
ex: fingertips
Big muscles - correct answer ✔✔1:2000, neuron to fiber
ex: leg muscles
,Increase motor units = - correct answer ✔✔increase fibers shortening, increase cross bridges,
greater amount of force
Twitch - correct answer ✔✔smallest amount of force (single AP)
Twitch summation - correct answer ✔✔AP happens before complete relaxation, strengthening
contraction within the fiber
Tetanus - correct answer ✔✔Rapid AP maxes out contraction
Muscle contraction depends on - correct answer ✔✔force, which muscles are contracted, which
muscles are relaxed
Isometric contraction - correct answer ✔✔no movement
Length of muscle in isometric contraction - correct answer ✔✔no change in muscle length,
constant
Force of contraction is ____ to the weight of the object in isometric contraction - correct answer
✔✔equal
Opposing muscles in an isometric contraction contract _____ - correct answer
✔✔simultaneously
agonist and antagonist pairs ex - correct answer ✔✔biceps, triceps
isotonic contraction - correct answer ✔✔movement
, the force in an isotonic contraction is ____ than the weight of the object - correct answer
✔✔greater
agonist in isotonic - correct answer ✔✔shortens
antagonist in isotonic - correct answer ✔✔relaxes by reflex action
life something heavy = - correct answer ✔✔more motor recruitment
muscle length in isotonic contraction - correct answer ✔✔changes
Parallel elastic component PEC - correct answer ✔✔passive elasticity derived from muscle
membranes
Series elastic component SEC - correct answer ✔✔passive elasticity derived from tendons when
a tensed muscle is stretched
active state of muscle - correct answer ✔✔the formation of bonds between myosin and actin
and subsequent internal shortening of contractile component
what is needed for active state of muscle - correct answer ✔✔Ca2+
Low tension (short) - correct answer ✔✔no space for sliding
Highest tension - correct answer ✔✔-muscle length normal
-most optimal for sliding
answered 2025/2026
How does a nerve connect to a muscle fiber in vertebrae skeletal muscle? - correct answer
✔✔Each muscle fiber is connected to one motor neuron only at one spot.
Motor Unit - correct answer ✔✔all muscle fibers connected to one motor axon
How do motor units contract? - correct answer ✔✔all-or-none
How doe muscles create contractions of different forces and duration? - correct answer
✔✔Recruitment of different types/numbers of motor units
Weak stimuli - correct answer ✔✔activates neurons with low thresholds
Strong stimuli - correct answer ✔✔activates neurons with higher thresholds
The ____ motor units recruited, the ____ the force generated - correct answer ✔✔more,
greater
Fine control - correct answer ✔✔1:1, neuron to fiber
ex: fingertips
Big muscles - correct answer ✔✔1:2000, neuron to fiber
ex: leg muscles
,Increase motor units = - correct answer ✔✔increase fibers shortening, increase cross bridges,
greater amount of force
Twitch - correct answer ✔✔smallest amount of force (single AP)
Twitch summation - correct answer ✔✔AP happens before complete relaxation, strengthening
contraction within the fiber
Tetanus - correct answer ✔✔Rapid AP maxes out contraction
Muscle contraction depends on - correct answer ✔✔force, which muscles are contracted, which
muscles are relaxed
Isometric contraction - correct answer ✔✔no movement
Length of muscle in isometric contraction - correct answer ✔✔no change in muscle length,
constant
Force of contraction is ____ to the weight of the object in isometric contraction - correct answer
✔✔equal
Opposing muscles in an isometric contraction contract _____ - correct answer
✔✔simultaneously
agonist and antagonist pairs ex - correct answer ✔✔biceps, triceps
isotonic contraction - correct answer ✔✔movement
, the force in an isotonic contraction is ____ than the weight of the object - correct answer
✔✔greater
agonist in isotonic - correct answer ✔✔shortens
antagonist in isotonic - correct answer ✔✔relaxes by reflex action
life something heavy = - correct answer ✔✔more motor recruitment
muscle length in isotonic contraction - correct answer ✔✔changes
Parallel elastic component PEC - correct answer ✔✔passive elasticity derived from muscle
membranes
Series elastic component SEC - correct answer ✔✔passive elasticity derived from tendons when
a tensed muscle is stretched
active state of muscle - correct answer ✔✔the formation of bonds between myosin and actin
and subsequent internal shortening of contractile component
what is needed for active state of muscle - correct answer ✔✔Ca2+
Low tension (short) - correct answer ✔✔no space for sliding
Highest tension - correct answer ✔✔-muscle length normal
-most optimal for sliding
