Chapter 6 Anatomy- Muscular System

Which of the following is NOT a function of the muscular system?

Blood cell formation

A nursing infant develops a powerful sucking muscle that adults also use for whistling or blowing a trumpet called the ________.

Buccinator

Why are calcium ions necessary for skeletal muscle contraction?

Calcium ions trigger the binding of myosin heads to actin filaments

Striated involuntary muscle tissue is classified as ________ muscle.

Cardiac

Striated involuntary muscle tissue found in the heart is ________.

Cardiac muscle

What enzyme breaks down acetylcholine into acetic acid and choline to prevent continued contraction of the muscle fiber?

Acetylcholinesterase

What must rush into a muscle cell to promote its depolarization?

Acetylcholinesterase

During skeletal muscle contraction, to what do myosin heads bind?

Actin filaments

What is the unstoppable electrical current that travels down the length of the entire surface of a sarcolemma?

Action potential

The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is called the ________.

Synaptic cleft

A skeletal muscle twitch differs from a tetanic contraction in that ________.

The muscle twitch is a brief and "jerky" movement, while the tetanic contraction is prolonged and continuous

Sandra is playing the piano for her recital. Which muscle is NOT involved in the movement of her hands and/or fingers?

Extensor digitorum longus

Which of the following is an example of an isometric contraction?

Pushing against an immovable wall

The plasma membrane of a skeletal muscle cell is called the ________.

Sarcolemma

A smooth, sustained contraction, with no evidence of relaxation, is called ________.

Fused, or complete, tetanus

Which muscle forms the curved calf of the posterior leg?

Gastrocnemius

Anaerobic glycolysis requires ________ to make ATP.

Glucose only

One neuron and all the skeletal muscles it stimulates is known as a ________.

Motor unit

An inherited disease that causes muscles to degenerate and atrophy is known as ________.

Muscular dystrophy

Creatine phosphate (CP) functions within the muscle cells by ________.

Storing energy that will be transferred to ADP to resynthesize ATP as needed

Which of the following muscles acts as a synergist to masseter and closes the jaw?

Temporalis

A sarcomere is ________.

The contractile unit between two Z discs

The condition of skeletal muscle fatigue can be best explained by ________.

The inability of the muscle to contract even if it is being stimulated

Which one of the following is composed mostly of the protein myosin?

Thick filaments

Which of these muscles is the prime mover of elbow extension?

Triceps brachii

Which facial muscle is considered the "smiling" muscle since it raises the corners of the mouth?

Zygomaticus

What creates the alternating light and dark bands that provides the striation pattern on skeletal muscle tissue?

A bands and I bands

What is acetylcholine?

A neurotransmitter that stimulates skeletal muscle to contract

The mechanical force of contraction is generated by ________.

A sliding of thin filaments past thick filaments

Which movement is opposite to abduction?

Adduction

The heads of the myosin myofilaments are called ________ when they link the thick and thin filaments together during skeletal muscle contraction.

Cross bridges

The epimysium is represented by ________.

Label A

What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract?

Acetylcholine

Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?

Acetylcholine (ACh) binds to receptors on the sarcolemma and allows passage of sodium ions into the cell

Which muscle group adducts the thighs?

Adductor group

Which method of regenerating ATP during muscle contraction can produce lactic acid?

Aerobic cellular respiration

What is covered by the endomysium?

An individual muscle cell

Muscles that perform opposite actions to one another are termed ________.

Antagonists

Neurotransmitters are released upon stimulation from a nerve impulse from the ________.

Axon terminals of the motor neuron

The arrangement of fascicles in orbicularis oris is ________.

Circular

Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ________.

Contractility

The prime mover of arm abduction is the ________ muscle.

Deltoid

Skeletal muscle, as a whole, can generate different amounts of force, and different degrees of shortening, in response to stimuli. What is this concept called?

Graded response

Contractions in which muscles shorten and produce movement are known as ________.

Isotonic contractions

What is the main function of the quadriceps group?

Knee extension

The A band within a myofibril is indicated by ________.

Label A

The I band within a skeletal muscle fiber is indicated by ________.

Label B

The endomysium that wraps individual muscle fibers is indicated by ________.

Label B

The myofilament composed of actin is indicated by ________.

Label C

The perimysium wraps a fascicle of muscle cells and is represented by ________.

Label C

The H zone, located within the A band, lacks thin filaments and is represented by ________.

Label D

The muscle fiber (cell) is indicated by ________.

Label D

Which of the following is a type isometric exercise in which muscles increase in size and strength?

Lifting weights

A motor neuron and all of the skeletal muscle fibers it stimulates are termed a ________.

Motor unit

According to the sliding filament theory, how does muscle contraction occur?

Myosin heads form cross bridges and pull thin filaments, causing them to slide.

The point of muscle attachment to an immovable or less movable bone is known as the ________.

Origin

Which of these muscles is located on the ventral (anterior) side of the body?

Pectoralis major

Which muscle helps compress the abdominal contents during defecation or childbirth?

Rectus abdominis

What organelle wraps and surrounds the myofibril and stores calcium?

Sarcoplasmic reticulum

Which type of muscle tissue contracts most quickly upon stimulation?

Skeletal

The type of muscle tissue pictured in Figure 6.3 is ________.

Smooth muscle

Which term does NOT describe smooth muscle cells?

Skeletal

Jason injured his hamstring muscle group during football practice. He will be unable to perform ________.

Thigh extension and knee flexion