CH 13

What do smooth, cardiac, and skeletal muscle all have in common? A. They are all uninucleated. B. They are all striated. C. They are all found in the walls of blood vessels. D. The cells of these muscles are all called muscle fibers. E. They all interlock at intercalated disks.

Of the three types of muscle tissue, which has multinucleated fibers? A. smooth muscle B. cardiac muscle A. They are all uninucleated. D. both smooth and skeletal muscles E. both cardiac and smooth muscles

Of the three types of muscle tissue, which is voluntary? A. smooth muscle B. cardiac muscle C. skeletal muscle D. both smooth and skeletal E. both cardiac and skeletal

Of the three types of muscle tissue, which is not striated? A. smooth muscle B. cardiac muscle C. skeletal muscle D. skeletal and smooth lack striations E. cardiac and smooth lack striations

Skeletal muscle contractions play a role in returning the venous blood to the heart. TRUE/FALSE

What is found within the intercalated disks of cardiac muscle? A. sarcoplasmic reticulum B. gap junctions C. dense connective tissue D. bone E. myoglobin

List the functions of the skeletal muscles.

Because the heart beats continuously, cardiac fibers never relax completely. TRUE/FALSE

Explain the structural differences between the thick and thin myofilaments.

Which of the following is not a function of skeletal muscles? A. pumping of blood throughout the body B. support C. movement of bones D. maintenance of body temperature E. protection of internal organs

Explain the differences between fast-twitch and slow-twitch muscle fibers.

From the outside of a muscle coming in, the first thing encountered would be A. fascia. B. fascicle. C. dense connective tissue. D. muscle fiber. E. myofibril.

What structure attaches a muscle to a bone? A. ligaments B. tendons C. bursae D. sarcolemma E. sarcoplasm

What muscle works in a pair with the biceps brachii? A. the triceps brachii B. the trapezius C. the masseter D. the pectoralis major E. the sartorius

Muscles can only pull; they cannot push. TRUE/FALSE

The origin of a muscle is on a stationary bone. TRUE/FALSE

Which of the following is not a term that refers to how muscles work? A. prime mover B. synergists C. antagonist D. synergism E. origin

What is the deltoid muscle shaped like? A. a long thin line B. a square C. a triangle D. a circle E. a trapezoid

What does the word brevis mean when referring to a muscle? A. large B. small C. huge D. long E. short

What is the name of the muscle that is responsible for blinking and winking? A. latissimus dorsi B. trapezius C. pectoralis major D. orbicularis oculi E. extensor digitorum

What information does the word rectus give you about a muscle? A. the size of the muscle fibers B. the attachment of the muscle fibers C. the action of the muscle fibers D. the shape of the muscle fibers E. the direction of muscle fibers

Which of the following does not attach to the sternocleidomastoid muscle? A. rib B. clavicle C. sternum D. mastoid process E. skull

Which way does the adductor longus move the thigh? A. away from the midline B. toward the midline C. in a circle D. in a cone E. towards the back

What is the biggest muscle (in terms of mass) in the body? A. gluteus maximus B. sartorius C. stapedius D. quadriceps femoris E. latissimus dorsi

What does the word sarco mean? A. large B. short C. muscle D. tubule E. smooth

Several of the structures in the muscle cell are given special names. For example, the cytoplasm of a muscle fiber is called the sarcoplasm. Which of the following is truly a unique structure to muscle cells (not just a renamed one)? A. cytoplasm B. nucleus C. endoplasmic reticulum D. transverse (T) system E. plasma membrane

A muscle fiber is made up of many A. muscle cells. B. T tubules. C. myofibrils. D. fascicles. E. bursa.

One sarcomere A. extends from Z line to Z line. B. is composed of many myofibrils. C. contains only actin fibers. D. is composed of many muscle fibers. E. surrounds each muscle in the body.

What ion is responsible for initiating muscle contraction? A. Mg2+ B. Ca2+ C. H+ D. Cl- E. Na+

When a muscle contracts, the H zone almost disappears. TRUE/FALSE

What happens to the actin and myosin filaments when a muscle contracts? A. both of them shorten B. both of them lengthen C. both stay the same length D. actin shortens while myosin lengthens E. myosin shortens while actin lengthens

What supplies the energy for muscle contraction? A. actin B. myosin C. tropomyosin D. ATP E. Ca2+

Each actin molecule is shaped like a golf club, with a straight portion ending in a globular head. TRUE/FALSE

What does troponin bind to and what happens when it binds? A. Ca2+, tropomyosin shifts B. tropomyosin, the sarcomere relaxes C. acetylcholine, the sarcome shortens D. ATP, tropomyosin returns to normal position E. T tubules, the sarcomere shortens

What is the name of the small gap that separates the axon terminal of a nerve from the sarcolemma? A. T tubule B. sliding filament C. synaptic cleft D. synaptic vesicle E. sarcoplasmic reticulum

When the nerve signal reaches the axon terminal what happens next? A. The muscle contracts. B. The synaptic vesicles release neurotransmitter. C. An electrical signal is formed that jumps the synaptic cleft. D. H+ is pumped into the synaptic cleft. E. Myosin is released from the axon terminal.

One motor neuron activates one muscle fiber. TRUE/FALSE

One motor unit obeys a principle called the all-or-none law. TRUE/FALSE

Why is the innervation ratio in the ocular muscles one motor axon per 23 muscle fibers, whereas in the gastrocnemius muscle it is one motor axon per 1000 muscle fibers? A. There are more nerves in the upper body than in the lower extremities. B. The ocular muscles require finer control than moving the legs. C. The innervation ratio has to do with the overall size of the muscle--the bigger the muscle, the fewer the muscle fibers per motor axon. D. The gastrocnemius muscle contracts much harder than the ocular muscles do. E. There are fewer muscle fibers in the gastrocnemius muscle than in the ocular muscles.

Which of the following is not a phase of a single muscle twitch? A. stimulation period B. latent period C. contraction period D. relaxation period E. none of these are phases of a muscle twitch

What is happening during the latent period of a muscle twitch? A. The muscle relaxes and returns to its former length. B. Fresh ATP binds to the myosin causing it to return to its resting position. C. ADP and phosphate are released, and the power stroke of the contraction occurs. D. The myosin-actin cross-bridges are broken and the sarcomere shortens. E. The neurotransmitter is diffusing across the synaptic cleft causing an electrical signal in the muscle cell.

Which of the following does not occur when a muscle fatigues? A. Its energy reserves are depleted. B. Stimulation continues. C. Tetanus is achieved. D. Acetylcholine is crossing the synaptic cleft. E. The muscle relaxes.

In good muscle tone, how many motor units are contracted? A. none B. some C. all D. 5 -10% of the motor units E. 10 - 15% of the motor units

Contraction of a muscle requires all the motor units to be undergoing tetanic contraction. TRUE/FALSE

Which of the following is not an energy source for muscle contraction? A. glycogen B. triglycerides C. glucose D. fatty acids E. starch

Which of the following is not a source of ATP for muscle contraction? A. ATP in the blood B. ATP stored in the cell C. the creatine phosphate pathway D. fermentation E. aerobic respiration

Of the three pathways for obtaining ATP for muscle contraction, which one requires oxygen? A. only the creatine phosphate pathway B. only fermentation C. only respiration D. fermentation and respiration E. the creatine phosphate pathway and fermentation

Of the three pathways for supplying ATP to the muscle, which pathway(s) do slow-twitch fibers prefer? A. the creatine phosphate pathway B. fermentation C. aerobic respiration D. the creatine phosphate pathway or fermentation E. the creatine phosphate pathway or aerobic respiration

Jillian is a top level cross country runner due to her having predominantly slow-twitch muscle fibers. TRUE/FALSE

Why are slow-twitch muscles dark? A. They have many more myofibrils per motor unit than fast-twitch fibers. B. They are designed for strength and explosions of energy. C. They need less blood than fast-twitch fibers. D. They contain myoglobin. E. They have fewer mitochondria.

What is the name of a sudden and involuntary muscular contraction, often accompanied by pain? A. bursitis B. sprain C. strain D. tic E. spasm

What is the difference between a tic and a spasm? A. A tic is a spasm that can be controlled voluntarily. B. A tic is a strong, and very painful spasm, especially of the leg and foot. C. A tic is caused by stretching or tearing of a muscle, while a spasm is just an involuntary contraction. D. A tic is caused by the inflammation of a tendon, while a spasm is just an involuntary contraction. E. A tic refers to achy muscles, usually due to over exercise, while a spasm is just an involuntary contraction.

Which of the following injuries is most likely to happen to the ankle? A. sprain B. strain C. convulsion D. bursitis E. muscular dystrophy

Fibromyalgia is a temporary condition of achy muscles, usually due to overuse. TRUE/FALSE

Which muscle injury is characterized by a twisting of a joint leading to swelling and injury? A. sprain B. strain C. tendinitis D. bursitis E. myalgia

Which disease is an autoimmune disease characterized by weakness that especially affects the muscles of the eyelids, face, neck, and extremities? A. myalgia B. muscular dystrophy C. myasthenia gravis D. tendinitis E. bursitis

Leiomyomas are a type of smooth muscle cancer that occurs in the uterine wall. TRUE/FALSE

What is the reservoir for Ca2+ in the body? A. muscles B. bones C. liver D. brain E. blood

Which of the following does not occur when you are very, very cold? A. More blood flows to the surface of the body. B. Smooth muscle contracts inside the blood vessels supplying the skin. C. The arrector pili muscles contract. D. Shivering occurs. E. You get goose bumps.

What happens when the arrector pili muscles contract? A. Your head nods "yes." B. Your leg kicks out. C. The hairs on your skin stand on end. D. The blood from your skin is rerouted to your core. E. You tap your finger.

Temperature sensitive neurons in the skin are responsible for initiating shivering. TRUE/FALSE

If you lock your knees while standing you may pass out because of the lack of venous return to the heart. TRUE/FALSE