Ch 10 Anatomy

What part of a muscle twitch begins as a repetitive power stroke, then pulls the thin filaments past the thick filaments, shortening the sarcomeres?

Contraction period

Concentric contraction and eccentric contraction are both types of what major type of muscle tension?

Istonic contraction

Which of the following will increase during strenuous muscular activity?

Lactate

In a 1500-meter run, an event that may take about 5 to 6 minutes, ATP is supplied by which energy sources?

Phosphagens, anaerobic, and aerobic sources

Which of the following refers to a sustained muscle contraction?

Tetanus

Lack of ATP is currently considered to be a primary cause of muscle fatigue

false

Lack of ATP is currently considered to be a primary cause of muscle fatigue.

false

Multiunit smooth muscle cells are stimulated to contract in unison, whereas single-unit smooth muscle cells receive stimulation to contract individually.

false

Multiunit smooth muscle is characterized by the use of gap junctions between cell membranes.

false

Myoglobin provides muscle fibers with a means of supplying ATP anaerobically.

false

Relaxation of smooth muscle is faster than skeletal muscle.

false

Smooth muscle is not located in the respiratory system.

false

Sprinting is a sport that requires an explosion of energy more than endurance. The best type of muscle fibers for this activity would be

fast-twitch fibers with fewer mitochondria and a lower blood supply.

In the gluteus maximus, each motor unit controls a _____________ amount of muscle fibers than a motor unit in the eye muscles.

greater

If stimulation frequency continues to increase, wave summation may lead to

incomplete tetany.

The sequence for smooth muscle contraction is

increased cytosolic calcium, which binds to calmodulin in cytosol, complex binds with myosin light-chain kinase, which uses ATP to phosphorylate myosin head groups, which bind to actin filaments, resulting in contraction.

The sequence for skeletal muscle contraction is

increased cytosolic calcium, which binds to troponin, which moves tropomyosin from blocking active sites on actin filament, which binds with myosin head groups, resulting in contraction. Correct

Your school wins the homecoming football game against its biggest rival. You watch as the smallest cheerleader tries to lift up the heaviest linebacker in her excitement. As she strains against his 300-pound load and does not move him, what type of muscle contraction are her muscles experiencing?

isometric

The vascular supply to slow oxidative muscle fibers is ______ extensive than that of fast glycolytic muscle fibers.

more

The specialized region of the sarcolemma that has folds and indentations to increase the membrane surface area covered by the synaptic knob is the

motor end plate

Smooth muscle found in both the iris and ciliary muscle of the eye and arrector pili muscles in the skin is __________ smooth muscle.

multiunit

The component of a muscle fiber that quickly transports a muscle impulse from the sarcolemma throughout the entire muscle fiber is called the

transverse tubule (T-tubule).

ATP is continually consumed by a resting muscle fiber.

true

Embryonic myoblasts fuse to form single muscle fibers during development; thus skeletal muscle cells are multinucleated.

true

If a muscle fiber is experiencing tetany and stimulation continues, the muscle reaches fatigue.

true

One of the five important functions of skeletal muscle contraction is heat production.

true

Rising sarcoplasmic calcium levels results in contraction in both smooth muscle fibers and skeletal muscle fibers.

true

Smooth muscle cells lack transverse tubules.

true

Smooth muscle contraction and skeletal muscle contraction both involve thin filaments sliding over the thick filaments.

true

Some smooth muscle contractions are controlled by a pacemaker.

true

Weaker contractions occur in muscles that are overly stretched because there is minimal thick and thin filament overlap for crossbridge formation.

true

An individual is better at performing repeated muscle contractions under aerobic conditions if he or she has a greater percentage of _____ fibers in the muscles used in that activity.

type I

Stimulation of muscle fibers at a rate of 20 to 50 stimuli per second does not allow for complete relaxation of the fibers before the next stimulatory event. This results in _________ and can lead to incomplete tetany.

wave summation

Which of the following events does not occur during skeletal muscle relaxation?

ACh binds its receptor on the motor end plate.

The source of energy for bonding between myosin and actin is

ATP

The primary neurotransmitter at the neuromuscular junction is

Acetylcholine

Which of the following statements is true concerning calcium ions?

In smooth muscle, it binds with calmodulin.

Which is a characteristic of skeletal muscle from the selections below?

Multinucleated

Which of the following muscle characteristics characterize an effect of aging?

Slow, progressive loss of muscle mass

During wave summation,

a second stimulus arrives at the muscle before complete relaxation of the first contraction, causing the second contraction to have greater tension than the first one.

Cardiac muscle tissue contains fewer mitochondria than are found in skeletal muscle tissue.

false

Each muscle fiber may contract completely, partially, or not at all, depending on the strength of the stimulus.

false

If you were studying the neurotransmitter released from axon terminals at a neuromuscular junction, you would be studying

acetylcholine.

A decrease in muscular activity or damage to neurons that attach to skeletal muscle can lead to a reduction in the size of muscle called

atrophy.

The sarcolemma of smooth muscle cells has small invaginations called

caveolae.

During relaxation, passive tension in _______ is released.

connectin

The axon of a motor neuron travels through the epimysium and perimysium, and enters the _________, where it delivers a nerve impulse to an individual ________.

endomysium; muscle fiber

A bodybuilder exhibits an increase in muscle size, called hyperplasia.

false

The amount of additional oxygen that must be inhaled following exercise to restore pre-exercise conditions is called

oxygen debt

An extensive network of blood vessels and nerve fibers extends through both the epimysium and the _____ of a muscle.

perimysium

If you were studying the functions of skeletal muscle, you would be studying all of the following except

production of blood cells

The contractile unit of a myofibril is called the

sarcomere

_________ smooth muscle cells are stimulated to contract in unison (syncytium).

single unit

At the ends of muscles, the connective tissues merge to form a __________, which attaches the muscle to other structures.

tendon

During tetany,

the stimuli arrive at the muscle fiber so rapidly that there is no muscle relaxation between stimuli, but rather, a continuous contraction of the muscle fiber.

The resting tension in a muscle generated by involuntary nervous stimulation is called

tone