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Problem 1
The connective tissue covering that encloses the sarcolemma of an individual muscle fiber is called the:
a. Epimysium
b. Perimysium
c. Endomysium
d. Periosteum
Problem 2
A fascicle is a:
a. Muscle
b. Bundle of muscle fibers enclosed by a connective tissue sheath
c. Bundle of myofibrils
d. Group of myofilaments
Problem 3
Thick and thin myofilaments have different compositions. For each descriptive phrase, indicate whether the filament is, a. thick or b. thin.
_____ (1) contains actin
_____ (2) contains ATPases
_____ (3) attaches to the Z disc
_____ (4) contains myosin
_____ (5) contains troponin
_____ (6) does not lie in the I band
Problem 4
The function of the T tubules in muscle contraction is to:
a. Make and store glycogen
b. Release Ca²⁺ into the cell interior and then pick it up again
c. Transmit the action potential deep into the muscle cells
d. Form proteins
Problem 5
The sites where the motor nerve impulse is transmitted from the nerve endings to the skeletal muscle cell membranes are the
a. neuromuscular junctions
b. sarcomeres
c. myofilaments
d. Z discs
Problem 6
Contraction elicited by a single brief stimulus is called:
a. A twitch
b. Temporal summation
c. Multiple motor unit summation
d. Fused tetanus
Problem 7
A smooth, sustained contraction resulting from very rapid stimulation of the muscle, in which no evidence of relaxation is seen, is called:
a. A twitch
b. Temporal summation
c. Multiple motor unit summation
d. Fused tetanus
Problem 8
Characteristics of isometric contractions include all but:
a. Shortening
b. Increased muscle tension throughout the contraction phase
c. Absence of shortening
d. Used in resistance training
Problem 9
During muscle contraction, ATP is provided by:
a. a coupled reaction of creatine phosphate with ADP
b. aerobic respiration of glucose, and
c. anaerobic glycolysis.
______ (1) Which provides ATP fastest?
______ (2) Which does (do) not require that oxygen be available?
______ (3) Which provides the highest yield of ATP per glucose molecule?
______ (4) Which results in the formation of lactic acid?
______ (5) Which has carbon dioxide and water products?
______ (6) Which is most important in endurance sports?
Problem 10
The neurotransmitter released by somatic motor neurons is:
a. Acetylcholine
b. Acetylcholinesterase
c. Norepinephrine
Problem 11
The ions that enter the skeletal muscle cell during the generation of an action potential are
a. Calcium ions
b. Chloride ions
c. Sodium ions
d. Potassium ions
Problem 12
Myoglobin has a special function in muscle tissue. It:
a. Breaks down glycogen
b. Is a contractile protein
c. Holds a reserve supply of oxygen in the muscle
Problem 13
Aerobic exercise results in all of the following except:
a. More capillaries surrounding muscle fibers
b. More mitochondria in muscle cells
c. Increased size and strength of existing muscle cells
d. More myoglobin
Problem 14
The smooth muscle type found in the walls of digestive and urinary system organs and that exhibits gap junctions and pacemaker cells is:
a. Multi unit
b. Unitary
Problem 15
Name and describe the four special functional abilities of muscle that are the basis for muscle response.
Problem 16
Distinguish between
a. Direct and indirect muscle attachments and
b. A tendon and an aponeurosis
Problem 17
What is the importance of acetylcholinesterase in muscle cell contraction?
Problem 18
Explain what is meant by the term excitation-contraction coupling.
Problem 19
Define and draw a motor unit.
Problem 20
True or false: Most muscles contain a predominance of one skeletal muscle fiber type. Explain the reasoning behind your choice.
Problem 21
Describe some cause(s) of muscle fatigue and define this term clearly.
Problem 22
When a suicide victim was found, the coroner was unable to remove the drug vial clutched in his hand. Explain the reasons for this. If the victim had been discovered three days later, would the coroner have had the same difficulty? Explain.
Problem 23
a. Describe the structure of a sarcomere and indicate the relationship of the sarcomere to myofilaments.
b. Explain the sliding filament model of contraction using appropriately labeled diagrams of a relaxed and a contracted sarcomere.
Problem 24
Explain how a slight (but smooth) contraction differs from a vigorous contraction of the same muscle. Use the concepts of multiple motor unit summation.
Problem 25
Smooth muscle has some unique properties, such as low energy usage, and the ability to maintain contraction over long periods. Tie these properties to the function of smooth muscle in the body.
Problem 26
Muscle-relaxing drugs are administered to a patient during major surgery. Which of the two chemicals described next would be a good skeletal muscle relaxant and why?
• Chemical A binds to and blocks ACh receptors of muscle cells.
• Chemical B floods the muscle cells' cytoplasm with Ca²⁺.