A & P exam 2: Muscular system – Flashcards

What is the functional unit of a skeletal muscle called? a. a sarcomere b. a myofilament c. a myofibril d. the sarcoplasmic reticulum

The major function of the sarcoplasmic reticulum in muscle contraction is to ________. a. make and store phosphocreatine b. synthesize actin and myosin myofilaments c. provide a source of myosin for the contraction process d. regulate intracellular calcium concentration

An increase in the calcium ion level in the sarcoplasm starts the sliding of the thin filaments. -true -false

Which of the following would be recruited later in muscle stimulation when contractile strength increases? a. motor units with the longest muscle fibers b. many small motor units with the ability to stimulate other motor units c. large motor units with small, highly excitable neurons d. motor units with larger, less excitable neurons

Which of the following is the correct sequence of events for muscle contractions? a. motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments b. neurotransmitter release, muscle cell action potential, motor neuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power stroke c. muscle cell action potential, neurotransmitter release, ATP-driven power stroke, calcium ion release from SR, sliding of myofilaments d. neurotransmitter release, motor neuron action potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke

Which structures contain visceral smooth muscle? a. lungs and stomach b. small blood vessel walls and lungs c. stomach and urinary bladder d. urinary bladder and small blood vessel walls

The outermost connective tissue layer of a muscle is the a. ectomysium. b. endomysium. c. epimysium. d. perimysium.

muscles that help maintain upright posture as fixators -true -false

Which three muscles make up the hamstring muscle? a. biceps femoris, semitendinosus, semimembranosus b. gluteal, quadriceps femoris, biceps femoris c. quadriceps femoris, gluteal, biceps femoris d. semitendinosus, semimembranosus, gluteal

When the term biceps, triceps, or quadriceps forms part of a muscle's name, what does it tell you about the muscle? a. The muscle has two, three, or four origins, respectively. b. The muscle is able to change direction twice, three times, or four times faster than other muscles, respectively. c. The muscle has two, three, or four functions, respectively. d. The muscle has two, three, or four insertions, respectively.

Muscles that help to maintain posture are often called synergists. -True -False

During muscle contraction, myosin cross bridges attach to which active sites? a. myosin filaments b. actin filaments c. Z discs d. thick filaments

The triceps brachii muscle is partially named based on a. its action. b. its location. c. its size of its fibers. d. the direction its fibers run.

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________. A. a strong base B. stearic acid C. hydrochloric acid D. lactic acid

The ________ is the main chewing muscle and is assisted by the temporalis.

Another name for a skeletal muscle cell is a skeletal muscle A. fiber. B. myofibril. C. sarcoplasmic reticulum. D. tubule.

What is the functional role of the T tubules? A. stabilize the G and F actin B. allow electrical charge to travel deep into cell C. hold cross bridges in place in a resting muscle D. synthesize ATP to provide energy for muscle contraction

Groups of cardiac muscle cells adapt their contraction rate to A. the average contraction rate of all the cells. B. the contraction rate of the fastest cell. C. the contraction rate of the slowest cell. D. the median contraction rate of all the cells.

Smooth muscle is classified as A. involuntary nonstriated muscle. B. involuntary striated muscle. C. voluntary nonstriated muscle. D. voluntary striated muscle.

What type of muscle controls the movement of an animal's skeleton? A. involuntary nonstriated muscle B. involuntary striated muscle C. voluntary nonstriated muscle D. voluntary striated muscle

Which of the following is NOT a muscle primarily involved in the breathing process? A. diaphragm B. external intercostal C. internal intercostal D. latissimus dorsi

The internal abdominal oblique muscle is partially named based on A. its action. B. the direction its fibers run. C. the number of its heads. D. the shape of its fibers.

When skeletal muscle contracts, which site undergoes the greatest movement? A. belly of the muscle B. head of the muscle C. insertion of the muscle D. origin of the muscle

A skeletal muscle that contracts at the same time as the prime mover muscle and assists in carrying out the prime mover's action is a/an A. agonist. B. antagonist. C. fixator. D. synergist.

Muscles are only able to pull, they never push. -True -False

The oxygen-binding protein found in slow-twitch (red) muscle cells is ________. A. hemoglobin B. ATP C. myoglobin D. immunoglobin