Quiz #4 Flashcards
The Motor neuron and all the muscle fibers it innervates is called a
motor unit
The two prinicipal contractile protein filaments found in skeletal muscle are
actin and myosin
TRUE OR FALSE: At any given velocity of movement, the peak force is greater in muscles that contain a high percentage of fast twitch fibers when compared to muscles that possess predominantly slow twitch fibers
True
Fast-Twitch fibers contain a relatively
small number of mitochondria and high ATPase activity
The trigger to initiate the contractile process in skeletal muscles is
calcium binding to troponin
During the initial period of disuse (i.e., 2 days), muscle atrophy is predominantly due to
decreased protein synthesis
The site where the motor neuron and muscle cell meet is called the
motor unit
TRUE OR FALSE: In sprinting type activities, ONLY fast twitch muscle fibers are recruited
True
Calcium is stored in muscle within the
sarcoplasmic reticulum
Type IIx fibers __________.
have high specific tension
Which of the following ECGs indicates myocardial ischemia?
ST Segment depression
All the gas exchange between the vascular system and tissues occur in
Capillaries
The back flow of blood from left ventricle to the left atrium is prevented by the
Bicuspid Valve
Diastolic Pressure provides an indication of:
Peripheral Resistance
The pacemaker potential of the heart is initiated by
inherent leakage of Na+
The earliest gains in strength training is primarily due to _________
All of the above
As exercise intensity increases
Viscera blood flow decreases
The ______ represents ventricular contraction during a recording of ECG of the heart
QRS complex
The volume of gas that reaches the respiratory zone (gas-exchange zone) of the lung is termed
Alveolar ventilation
Which is the predominant factor in Fick’s law of gas diffusion?
Partial pressure between the two sides of the tissue
During incremental exercise, ventilation increases as a linear function of oxygen uptake up to a point known as _________ where the ventilation increases exponentially.
Ventilatory threshold
During exercise, the increase in ventilation would _______.
All of the above
Baroreceptors are located in ______________.
Carotid Sinus
Which of the following factors does NOT cause an increase in stroke volume during strenuous exercise?
increase in heart rate
TRUE/FALSE During exercise an increase in alveolar ventilation serves to lower arterial PCO2 and maintain normal blood pH.
True
TRUE/FALSE The right shift of the oxygen-hemoglobin dissociation curve indicates the decrease in oxygen affinity to hemoglobin.
True
TRUE/FALSE At rest, inhalation is caused by diaphragm relaxation
FALSE
Which of the following is a characteristic of myocardium?
All of the above
In order to meet the increased oxygen demands of the active skeletal muscles during exercise, what adjustments in blood flow should be made?
Increase in cardiac output and a redistribution of blood flow from inactive tissue to the active skeletal muscles.
The most important variable that determines resistance to blood flow is _____
The radius of the vessel
Which of the following ejection fractions of the heart indicates depression of myocardial contraction?
The function of the baroreflex is to _______________.
Normalize blood pressure
Which of the following formulas can be used to calculate ejection fraction?
Ejection Fraction = SV/EDV
Which of the following factors would cause a decrease in EDV during high-intensity exercise?
Increased Heart Rate
Which of the following factors causes an increase in blood flow the most in the active skeletal muscles during exercise?
Increase in Sympathetic Nervous Activity
During a prolonged exercise (2 hours) in a hot weather and no water intake available, the hematocrit of the athlete would be ________.
Increased
Exercise at the intensity of ____________ VO2 max induces the greatest stroke volume.
40-60%
The fact that an increase in EDV increases the stroke volume of the heart is an illustration of ______.
the decrease in total peripheral resistance
Which of the following is NOT a right cardiovascular response of a healthy individual to a dynamic exercise?
increase in diastolic blood pressure
Compared with a leg exercise at the same workload, arm exercise tends to induce _________.
Higher HR (Not sure if this is correct)
TRUE/FALSE During heavy exercise, the heart may spend more time in systole than in diastole/
TRUE
During exercise the cardiovascular center I the brain stem that receives feedback from _______ and then adjusts the cardiovascular system to meet the need to exercise.
All of the above
The relationship between oxygen uptake, cardiac output, and the arterial-venous oxygen difference is described mathematically by the
Fick’s Equation
The most resistance to blood flow is in the _________.
Arterioles
Which of the following is true of the heart rate change during exercise?
the increase in HR is due to PNS withdrawal followed by increasing SNS influence
TRUE/FALSE Trained endurance runners have lower ventilatory threshold than untrained individuals because trained runners have adapted to the exercise
False
Person A has a VO2max value of 4 L/min. Person B has a VO2max value of 3 L/min. Based on the information above, which of the following statements is correct?
Their fitness levels cannot be compared based on the given information.
The hemoglobin level for a healthy man is about ________ g/dl.
15
Which of the following factors is NOT the right response to acute exercise?
Vasodilation in viscera
Oxygenated blood returns to the heart via the _____.
Pulmonary vein
The majority of CO2 in our body is transported by
Bicarbonate
TRUE/FALSE The increase in parasympathetic activity would significantly decrease the heart rate.
True
TRUE/FALSE Pulmonary artery contains deoxygenated blood
TRUE
TRUE/FALSE Hemoglobin can only carry oxygen
FALSE
Which of the following is the right blood flow pathway (starting with deoxygenated blood)?
Vena Cava -> Right Atrium -> Right Ventricle -> Lungs -> Left Atrium -> Left Ventricle -> Aorta
_______________ is defined as the maximum amount of gas that can be expired after a maximum inspiration.
Vital Capacity
Cardiovascular drift is characterized as ______________________.
Increase in heart rate and a decrease in stroke volume.
Which one of the following most likely causes cardiovascular drift?
Long duration exercise in a hot/humid weather
When exercise (prolonged exercise) at steady state in hot/humid environment ventilation tends to _____________.
Increase
