Human Anatomy Muscular System Mastering AP Questions

What is the term for a single motor neuron and all the muscle fibers it controls?

Motor unit

The thick filaments of sarcomeres are contained in which band? A. S band B. I band C. Z line D. A band

D. A band

Smooth muscle forms: A. Bundles B. Sheaths around other tissues C. Sheets D. All of the above

D. All of the above

Which muscle acts to depress the ribs? A. Transversus abdominis B. External intercostals C. Internal and external intercostals D. Internal intercostals

D. Internal intercostals

When you unsuccessfully attempt to lift a 300 pound weight off the ground, you are demonstrating: A. Hypertonic contraction B. Isotonic contraction C. Hypotonic contraction D. Isometric contraction

D. Isometric contraction

What structure is the functional unit of contraction in a skeletal muscle fiber?

The sarcomere

A muscle that may either provide additional pull near the insertion or stabilize the point of origin is called ___________.

synergist

Which muscle is NOT a part of the shoulder? A. Infraspinatus B. Brachialis C. Subscapularis D. Supraspinatus

B. Brachialis

The amount of tension produced by an individual muscle fiber ultimately depends on the: A. Presence of summation B. Number of pivoting cross bridges C. Length of the contraction phase D. All of the above

B. Number of pivoting cross bridges

What causes cross bridge detachment? A. Acetylcholine binds to receptors in the junctions folds of the sarcolemma B. ATP bonds to the myosin head C. ADP and inorganic phosphate are bound to the myosin head D. Calcium ions bind to troponin

B. ATP binds to the myosin head

Which describes the cause for the cessation of an action potential? A. Calcium ions bind to troponin B. Acetylcholinesterase breaks down acetylcholine C. The sarcoplasmic reticulum releases stored calcium ions

B. Acetylcholinesterase breaks down acetylcholine

Which describes a response of an organ system to exercise? A. Carbon dioxide is received by the cardiovascular system B. Blood vessels in the skin dilate to allow heat loss

B. Blood vessels in the skin dilate to allow heat loss

What kind of striated muscle is under involuntary control?

Cardiac

Which is NOT a characteristic of skeletal muscle? A. Guarding entrances and exits B. Supporting soft tissues C. Maintaining body temperature D. Producing blood cells

D. Producing blood cells

The basic repeating unit of a muscle fiber is called the: A. Sarcolemma B. Sarcoplasm C. Sarcoplasmic reticulum D. Sarcomere

D. Sarcomere

What is a triad?

A pair of terminal cisternae of the SR with a T-tubule between them

Neuromuscular Junction: What mechanism ensures a rapid and efficient removal of acetylcholine? Hint: removal happens in two ways, which one causes a rapid removal?

Acetylcholine is degraded by acetylcholinesterase

Unlike skeletal tissue, cardiac muscle tissue: A. Is voluntary and contains intercalated discs and myoglobin B. Is voluntary and contains branches cells and intercalated discs C. Is striated and contains intercalated discs and myoglobin

B. Is voluntary and contains branched cells and intercalated discs

Which type of chemical reaction is used to rebuild ADP into ATP? A. Hydrolysis B. Dehydration synthesis C. Rehydration synthesis

B. Dehydration synthesis

Which of the following is the layer of collagen fibers that surround the entire muscle? A. Perimysium B. Epimysium C. Exomysium D. Endomysium

B. Epimysium

Which statement concerning the recovery period of muscle activity is true? A. Heat is gained B. Lactic acid removal occurs C. The metabolic activity focuses on the production of lactic acidosis D. Glycolysis occurs at a high rate

B. Lactic acid removal occurs

NJ: Calcium entry into the axon terminal triggers which of the following events? A. Acetylcholine binds to its receptor B. Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine

B. Synaptic vesicles fuse to the plasma membrane of the axon terminal and release acetylcholine

Which statement regarding fast fibers is true? A. Their power comes from aerobic metabolism B. Their power comes from the anaerobic process of glycolysis C. They use the breakdown of carbohydrates, lipids, and amino acids for energy D. None of the above

B. Their power comes from the anaerobic process of glycolysis

What is a cross bridge?

A myosin head bound to actin

The structure that ties adjacent muscle fibers together is the: A. Endomysium B. Epimysium C. Fascicle D. Perimysium

A. Endomysium

Rigor Morris occurs due to lack of what molecule?

ATP

Which type of muscle fiber has a large quantity of glycogen and mainly uses glycolysis to synthesize ATP? A. Red slow twitch fibers B. White fast twitch fibers

B. White fast twitch fibers

When does the cross bridge cycling end?

Sufficient calcium has been actively transported back into the sarcoplasmic reticulum, allows calcium to unbind from troponin

How does the myosin head obtain the energy required for activation?

The energy comes from the hydrolysis of ATP.

Most of the ATP needed by muscle cells is provided through....

aerobic metabolism

A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in

incomplete tetanus

Acetylcholine binds to its receptor in the sarcolemma and triggers:

the opening of ligand-gated cation channels

In the contraction phase of a single muscle twitch, maximum tension is reached approximately how long after stimulation?

15 milliseconds

What specific event triggers the uncovering of the myosin binding site on actin? A. Calcium ions bind to troponin and change it's shape B. Sodium ions bind to troponin and change it's shape C. Calcium ions bind to tropomyosin and change it's shape D. Calcium release channels open in the sarcoplasmic reticulum, and calcium elevens rise in the sarcoplasm

A. Calcium ions bind to troponin and change it's shape

Which of the following stabilizes the positions of bones and joints by tending and firming the muscle? A. Muscle tone B. Muscle units C. Isometric contraction D. Muscle recruitment

A. Muscle tone

What is the name of the enzyme that normally breaks down Ach in the neuromuscular junction?

Acetylcholinesterase

Which is not a function of skeletal muscles? A. Maintain body temp B. Produce bone movement C. Contraction of the heart D. Maintain body posture

C. Contraction of the heart

Action potentials travel the length of the Avon's of motor neurons to the axon terminals. These motor neurons: A. Arise in the epimysium of a skeletal muscle and extend to individual skeletal muscle fibers B. Extend from the spinal cord to the sarcolemma of a skeletal muscle fiber C. Extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber D. Extend from the brain to the sarcolemma of a skeletal muscle fiber

C. Extend from the brain or spinal cord to the sarcolemma of a skeletal muscle fiber

Which occurs when tension production rises to a peak then very brief periods of relaxation occurs? A. Tension plateau B. Latency C. Incomplete tetanus D. Resting period

C. Incomplete tetanus

Unlike skeletal muscle tissue, smooth muscle tissue: A. Is involuntary, contains sarcomeres, and is not striated B. Is involuntary, contains thick and thin filaments organized into sarcomeres, and is not striated C. Is involuntary, lacks sarcomeres, and is not striated

C. Is involuntary, LACKS sarcomeres, and is not striated

Which appendicular muscle originates on the anterior superior spine of the ilium? A. Semi-membranous B. Gracilis C. Sartorius D. Pectineus

C. Sartorius

Where are calcium ions stored within the fiber? (Skeletal muscle, in cross bridge cycle video)

Calcium ions are stored in the sarcoplasmic reticulum

What is the prime mover of the glenohumeral joint (shoulder) during flexion?

Deltoid

What is the name of the bone cell that secretes acids and enzymes that dissolve the honey matrix and release stored minerals through osteolysis?

Osteoclasts

Lactic acidosis is recycled by converting it to which of the following compounds?

Pyruvate

Rank these smallest to largest: - muscle - myofibril - muscle fiber - sarcomere - H-band - fascicle

Smallest to largest: 1. H-band 2. Sarcomere 3. Myofibril 4. Muscle fiber 5. Fascicle 6. Muscle

During the start of a skeletal muscle contraction, calcium binds to which molecule?

Troponin