EXS 223 Chapter 4

The performance capacity of muscle is determined by which of the following nontrainable factors? A) fiber diameter B) nerve impulse frequency C) number of fibers D) capillary density of muscle

number of fibers

The contractile unit of a muscle is:

sarcomere

The three types of muscle in the human body are:

skeletal, smooth, cardiac

The contractions of smooth muscle are __________and___________and are very ______________.

slow; uniform; fatigue resistant

What type of muscle is under the control of the autonomic nervous system and under involuntary control? A) cardiac B) skeletal C) smooth D) A and C of the two above

D

Which of the following statement regarding muscle fiber types is true: A) The number of FT and ST fibers does not vary from one individual to another. B) Most skeletal muscles contain both FT and ST fibers. C) Individual performance differences cannot be attributed to the varying percentaes of the muscle fiber types. D) None of the above.

B

Which of the following statements about sarccomeres is false: A) Sarcomeres are organized in series within the muscle fiber. B) Each sarcomere is made up of two types of protein myofilaments; actin, the thick filament, and myosin, the thin filament. C) Projecting from each myosin filament are myosin bridges, the tiny contractile elements. D) Examining the sarcomere longitudinally we see the striations characteristic of skeletal muscle.

B

Which of the following statements regarding the differences between trained and untrained individuals is false? A) Trained individuals have a larger muscle mass and therefore can produce greater force. B)Trained individuals further develop strength only by improving intra-muscle coordination. C)Trained individuals can activate a larger number of muscle fibers to produce greater force. D)Trained individuals have a much smaller muscle force deficit.

B

Muscle fibers can be divided into two main types or categories (Type I and Type II) based on what distinction: A) abundance of striation B) angle of cross bridges C) time to reach maximum tension D) thickness of myofilaments

C

Which of the following statements about tendons is false: A) Tendons are bundles of collagen fibers. B) One end of the tendon is usually linked to bone and the other to a skeletal muscle. C) Like muscle, tendons also have the ability to shorten or contract. D) Tendons function to move various parts of the skeleton in response to skeletal muscle contraction.

C

Which of the following statements regarding muscle biopsy is false: A) It can determine muscle fiber type and metabolic characteristics. B) It involves anesthetic injection and a small incision in the skin and muscle fascia. C) It is a completely noninvasive procedure. D) It allows us to view capillaries surrounding the muscle fibers.

C

Which of the following statements regarding strength training is true: A) Biological adaptation is a process specific to strength training and skeletal muscle adaptation. B) Following strength training, mujscle mass increases before enzymatic adaptation. C) It is necessary to develop all the relevant muscles in a balanced manner in order to optimize high level inter-muscle coordination. D) In strength training, the adaptation process proceeds at the same rates for different functional systems and physiological processes.

C

Which of the following statements regarding the motor unit is false: A) Each muscle fiber is activated through impulses delivered via the motor end plate. B) A group of fibers activated via the same nerve is termed motor unit. C) Motor nerves extend from the brain to the muscle fibers. D) In a motor unit each muscle fiber has its own end plate.

C

Which of the following statements regarding activation threshold is false? A) A weak nerve impulse activates only those motor units that have a low threshold of activation, thereby generating a low contractile strength. B) Every motor unit has the same threshold that must be reached for activation to occur. C) A weak nerve impulse activates all motor units to a lesser degree, thereby generating a low contractile strength. D) Both B and C.

D

Which of the following statements regarding inter-muscle coordination is true: A) The interplay between the agonists and synergists is of particular importance to the quality of inter-muscle coordination. B) In order to achieve inter-muscle coordination, agaonist muscles relax while antagonist muscles contract during movement. C) The greater the participation of muscles and muscle groups, the smaller the importance of inter-muscle coordination for strength capacity. D) The interplay between agaonists and antagonists is of particular importance to the quality of inter-muscle coordination.

D

Which of the following statements regarding the motor unit is true? A) Each motor unit can consist of a different number of muscle fibers B) All muscle fibers of one particular motor unit are always the same fiber type. C) A muscle can be composed of a different number of motor units. D) All of the above.

D

If a nerve impuse does not reach the required magnitude, then ONLY SOME of the muscle fibers will contract.

F,

Highly trained individuals can us 95 % of the motor units of a muscle at the same time.

F, 85%

The prime mover is also known as the ANTAGONIST.

F, agonist

Cardiac muscle functions to provide the contractile activity of the heart and has an EXTRINSICALLY CONTROLLED beat.

F, intrinsic

Slow twitch fibers (also called WHITE fibers) are slow to fatigue

F, red

Each cell is surrounded by a connective tissue sheath called the SARCOMERE.

F, sarcolemma

SKELETAL muscle forms the walls of blood vessels and body organs.

F, smooth

The muscles surrounding the joint being moved and supporting it in the action are called FIXATORS.

F, synergists

Muscles work in perfrct synchrony. When one muscle CONTRACTS to move a bone. the ohter RELAXES.

T

Myosin is known as the THICK filament.

T

The number of motor units within a muscle is diretly related to the PRECISION required by that muscle.

T

The structure of muscle tissue determines its specific function.

T

The contraction of skeletal muscle is initiated by impulses in the _______________ neurons to the muscle and is usually under _____________control.

motor; voluntary