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WorksheetsKin 3600 Midterm 2
Total questions: 40
Worksheet time: 20mins
Which of the following is TRUE about "oxygen debt and deficit?"
Oxygen debt (EPOC) is always smaller than deficit
Oxygen debt (EPOC) is usually larger than deficit
Oxygen debt is always equal to deficit
Oxygen deficit is independent of exercise intensity
Oxygen debt is independent of aerobic fitness level
Which of the following is NOT responsible for oxygen debt?
Oxygen requirement of respiratory muscles (true)
Q10 effect (true)
Oxygen required for the synthesis of glycogen in the liver, from some of the lactic acid
Oxygen required for the replenishment of body's oxygen stores (true)
Oxidation of lactic acid in recovering muscles and heart
While exercising on cycle ergometer at a given absolute submaximal power output, e.g 100 W, aerobically highly trained individuals will develop:
Smaller O2 deficit that untrained individuals wrong
Larger O2 deficit than untrained indivduals
Smaller EPOC than untrained individuals
Larger EPOC than untrained individuals
1 and 3 only
During the plateau phase of a steady state exercise:
The O2 demand of the body is larger than the O2 supply
The O2 demand of the body is smlaller than the O2 supply
The production of lactic acid is zero
All the ATP required may be supplied by aerobic phosphorylation
Aerobic and anaerobic ATP resynthesis are equal
If the same athlete is performing comepetitive 200 m ; 1500 m ; and marathon (26 miles) runs on three different occasions the O2 deficit will be :
The largest in marathon
The largest in 200 m run
The largest in 1500 m run
The smallest in marathon
The smallest in 200 m run
Which of the following is NOT a factor in the sudden, dispropportional increase in blood lactic acid and concentration at lactate threshold?
Sudden switching on of anaerobic glycogenolysis
Vasoconstriction in liver and kidneys
Increased recruitment of FT muscle fibers
Hormonal stimulation of glycolysis
All of the above
What is the metabolic rate (kcal.min-1) of an individual exercising in calorimeter if the temperature of input water is 12C, the temperature of output water is 13.8C, and the rate of water flow is 3.5 kg.min-1?
42.0
48.3
6.3
0.51
1.94
The coupling agent between the excitation and contraction of muscle fibers is the
Ca++
Actic
Troponin
Tropomyosin
Myosin
The two principal contractile proteins found in skeletal muscle are
Actin and troponin
Actin and myosin
Actin and tropomyosin
Troponin and tropomyosin
Myosin and tropomyosin
All of the following are true about slow oxidative (SO) muscle fibers except:
They have high myoglobin concentration
They are within the relatively smaller motor units
They have a smaller diameter than FG fibers
They relax more slowly than FG fibers
They have a well-developed SR network
An alpha motor neuron together with all the muscle fibers it innervates is called
Motor Unit
Motor end plate
Neuromuscular junction
Fusimotor unit
Neuromuscular unit
Time to peak tension in a muscle fiber is affected mostly by the
Type of myosin ATPase
The number of cross-bridges in strong binding state
Rate of cross-bridge cycling
Rate of calcium release from the SR
Rate the calcium is pumped back into the SR
Which component of muscle fiber acts as a physical switch that turns muscular contractions on and off?
T-tubules and SR
Z-discs
Troponin-tropomyosin complex
Actomyosin complex
When a single alpha motor neuron is maximally stimulated:
All of the muscle fibers innervated by it will contract maximally
The whole muscle will contract maximally
SO muscle fibers will contract first followed by the contraction of FB fibers
The force of resulting contraction will depend on the size of the AP-s
Only the smallest fibers innervated by it will contract maximally
The greatest power output of a muscle occurs at approx what percentage of its Vmax?
10%
30%
75%
100%
110%
All of the following are true about motor units except
Larger motor units have higher FG so SO fiber ratio
In large motor unit some fibers may be SO, some FG, and some even FOG type
Larger motor units are innervated with larger alpha motor neurons
All of the muscles fibers in a motor unit are of the same type
A and b only
Aerobic endurance training will
Increase the aerobic capacity of SO fibers only
Increase the aerobic capacity of FG fibers only
Increase the aerobic capacity of both muscle fiber types
Result in a conversion of SO fibers to FG fibers
Cause hypertrophy of the FG fibers
Troponin acts to:
Stimulate the breakdown of CP
Transport the Ca++ from SR to Tropomyosin
Transport Ca++ from sarcoplasm to SR
Bind Ca++ ions
B and C only
High-resistance strength training results in all of the following changes in trained muscles except
Increased capillary density of the muscles involved
Increased total cross-sectional area of fast twitch fibers
Increased cross-sectional area of the trained muscles
All of the above
A and C only
Increase in muscle strength resulting from general strength training programs is due to all of the following except
Hypertrophy if both muscle fibers types
Decreased stimulation threshold of Alpha motoneurons
Decreased sensitivity of muscle spindles
Increased synchronization of motor unit contractions
Decreased inhibition from GTO-s
Slow-twitch muscle fibers
Are numerous in successful long distance swimmers
Have very low myoglobin content
Are primarily used in anaerobic activities
Are recruited in action last during long distance running
Contract slowly but relax faster
The absolute force developed by a muscle fiber depends on
The sarcoplasmic Ca++ concentration
The number of troponin molecules saturated with Ca++
The amount of overlap between the thick and thin filaments
The number of myofibrils in the muscle fiber
All of the above
The ultimate, basic structures responsible for force development in muscle is/are
Sarcomeres
Myofibrils
Titin
Cross-bridges
Myofilaments
Development of tetanic contractions in muscle fibers ultimately depends on
Fiber length
The maintenance of high sarcoplasmic Ca++ concentration
The size of the end plate potential
The amount of Acetylcholine released at the neuromuscular juntion
The number of motor units recruited
Which of the following is true about motor units?
All the motor units in a particular muscle are the same size
There is no relationship between the size of the motor unit and the size of the alpha motoneuron innervating it
Any given muscle may have combination of large and small motor units
The smallest motor units are usually found in large muscles
A and C only
All-or-none characteristics is applied to
Muscle fiber
Nerve fiber
Sarcomere
Myofibrils
A and B only
In a resting muscle “A” band contains
Thick filaments only
Both thick & thin filaments
Troponin and Tropomyosin only
Actin only
C and D only
During Muscular Contractions (shortening)
H zone becomes progressively larger
A band becomes progressively smaller
A band becomes progressively larger
A band remains at the same length
A and B only
In humans all of the voluntary muscular contractions are
Isometric -force without changing length
Isotonic length increases
Twitch
Tetanic
B and C only
Curare causes flaccid paralysis of skeletal muscles by:
Inhibiting the Acetylcholinesterase
Blocking the Acetylcholine receptors of the postsynaptic membrane
Blocking the Ca++ entry into the presynaptic terminals
Blocking the Na channels of the sarcolemma
Blocking the Acetylcholine release from the presynaptic membrane
All of the following is true about force-velocity relationship of muscular contraction except
The largest force is developed at the lowest velocity
When the velocity is 0 the developed force is also 0
When the velocity is 0 the developed force is also 0
For any given velocity of contraction FG fibers develop larger peak force
For any given force of contraction SO fibers contract at a lower velocity
Type of muscular actions that result in movement of body parts may be called (select all that applies)
Isometric
Static
Concentric -Muscles shortens during force production, Ecentric- muscles lengthens, Isokinetic, Isotonic-Concentric/ecocentric
So fibers relax slower because of the
Lower affinity of Troponin of calcium ions
Relatively poorly developed sarcoplasmic reticular network
Smaller diameter of SO fibers
Smaller number of cross-bridges involved in the contraction
SO fibers are innervated by slow conducting nerve fibers
Which of the following is true about the power-velocity relationship of muscular contraction?
The relationship between the contraction velocity and power output is linear
At very high velocities the power output may decrease
Power output is the highest when contraction velocity is 0
At very low velocities of contraction there is relatively a very small difference in power outputs between the comparable FG and SO muscle fibers
B and d only
In muscular contractions the nervous system progressively increases the force output of skeletal muscles mainly by:
Regulating the contraction velocity of each muscle fiber
Progressively releasing more Acetylcholine at the neuromuscular junction
Progressively recruiting larger and larger motor units into action
Progressively regulating the length of sarcomeres
Progressively regulating the amount of Ca++ released by the Sarcoplasmic Reticulum
All of the following are the functions of the conducting zone of lungs except
Humidifying the air
Compressing the air
Filtering the air
Warming the air
A and C only
Diffusion of respiratory gases across the respiratory membrane occurs due to the
Differences between the molecular weights
Concentration difference
Partial pressure difference
Temperature difference
A and C only
At normal harometric pressure oxygen is carried in the blood mainly by
Red blood cells
Blood plasma
White blood cells
Blood proteins
None of the above
The chemosensitive area (central chemoreceptors) ultimately responds to changes in:
pH of venous blood
Po2 of Pco2 of arterial blood
Po2 of cerebrospinal fluid
pH of cerebrospinal fluid
pH of arterial blood
Which of the following is a function of cardiovascular system?
Transport of oxygen and carbon dioxide
Transport of heat
Transport of hormones
Transport of nutrients such as glucose and free fatty acids *
All of the above
