Neuromuscular Functions Flashcards
Motor units are preferentially recruited following the Henneman size principle which means that large motorneurons are depolarized first.
True or False?
False
Under which of the following conditions does relaxation of the muscle occur?
when actin and myosin filaments return to their original states
With an isometric contraction, the muscle is able to overcome external resistance.
True or False
False
When lifting a constant load through a range of joint motion, the muscle is maximally contracted only at its weakest point in the range.
True of False?
True
A reflex arc involves:
Sensory stimuli sent to the central nervous system that sends out motor signals.
Individuals with the largest muscle cross-sections generate the most absolute force.
True or False
True
Which of the following bands widens in an eccentric action as the fibre lengthens during force generation?
A band
With endurance training there is a shift to higher ratios of Type I fibres and a reduction of Type IIA fibres.
True or False?
False
What is not a correct statement about the sliding-filament model of muscle contraction?
Actin crossbridges detach from the myosin filaments with energy from ATP hydrolysis
In certain instances, muscle fibres can be stimulated to stretch, rather than contract.
True or False?
False
High intensity exercise recruits predominantly slow-twitch motor units.
True or False?
False
A motorneuron consists of the cell body, several short dendritic fibres, and one long axon fibre that goes to skeletal muscle fibres.
True or False?
True
What is the term that represents a repeating pattern of two vesicles and a T-tubule in each Z region?
Triad
A motor unit contains only one specific muscle fibre type. Which of the following is not a muscle fibre type contained in a motor unit?
A. Type 1a
B. Type 1
C. Type 2
D. Type 2a
A. Type 1a
Eccentric contractions occur when:
A muscle lengthens during contraction.
There are two types of motor units which operate following the all-or-none law: one type consists of Type I fibres and the other of Type II.
True or False?
True
When a muscle contracts it always shortens.
True or False?
False
Muscle spindles are sensitive to both the rate of change in length as well as to the final length attained by the fibres.
True or False?
True
Muscle soreness can be prevented or reduced by what?
Stretching, and gradual increases in activity intensity.
What consists of the basic repeating unit between two Z lines and makes up the functional unit of the skeletal muscle?
sarcomere
What principle states that slow-twitch motor units with the lowest threshold for activation become selectively recruited during light-to-moderate effort?
size principle
Male and female athletes have?
The same fibre Type distribution and histochemical properties.
Muscle velocity and work output have a(n) ______ relationship.
inverse
The inhibitory action caused by what prevents actin-myosin interaction?
troponin
Which is the protein complex that is formed when crossbridges make contact with the actin filaments?
actomyosin complex
Longer muscle fibres exhibit a higher contractile velocity but a lower force-output capacity
True
What splits a phosphate from ATP and releases its stored mechanical energy as it straightens?
myosin
