Exam 3 HHP308
Muscle pH is generally
0.4-0.6 pH units lower than arterial pH
During exercise at sea level, young, healthy untrained subjects generally maintain exercise arterial PO2 within
10-12 mmHg of resting values
Under normal conditions at sea level, the partial pressure of oxygen in the alveoli region of the lung is
100mmHg
Repeated bouts of high intensity exercise (e.g., interval training) can reduce arterial pH to levels as low as
6.8-7.0
In the transition from rest to exercise, what is the distribution of cardiac output to the heart? A) the % of cardiac output is unchanged, but the volume of blood increases B) the % of cardiac output increases, and the volume of blood increases C) the % of cardiac output decreases, and the volume of blood increases D) the % of cardiac output is unchanged, and the volume of blood is unchanged
A
The increase in cardiac output that occurs during exercise is due to a. both an increase in mean arterial pressure and a decrease in vascular resistance. b. a decrease in vascular resistance only. c. an increase in mean arterial blood pressure only. d. an increase in heart rate and a decrease in mean arterial blood pressure
A
Which of the following factors can decrease blood pressure? A) systemic vasodilation. B) an increase in blood viscosity. C) an increase in stroke volume D) increased parasympathetic nervous system activity.
A
Which of the following is NOT a mechanism for increasing venous return during exercise? A) an increase in stroke volume B) venoconstriction C) skeletal muscle contractions D) rhythmic pattern of breathing provides a mechanical pump to increase venous return
A
Which of the following is the correct order of events pertaining to contraction of the left ventricle? A) The bundle branches depolarize, the ventricle contracts, the ventricular pressure increases, and blood exits the ventricle. B) The aortic volume increases, the ventricular pressure increases, the ventricle contracts, the bundle branches depolarize. C) The ventricular pressure increases, the bundle branches depolarize, the aortic volume increases, the ventricle contracts. D) The bundle branches depolarize, the ventricular pressure increases, the ventricle contracts, the aortic volume increases
A
f a person with ischemic heart disease experiences chest pain when their double product exceeds 20,000, which of the following combinations will produce angina? A) HR = 150, BP = 150/80 B) HR = 140, BP = 140/75 C) HR = 130, BP = 150/75 D)HR = 120, BP = 160/95
A
The arterial-venous oxygen difference A) increases as a function of exercise intensity. B) does not change during exercise. C) decreases as the exercise intensity increases. D0 is highest during submaximal exercise
A) increases as a function of exercise intensity
According to the Henderson-Hasselbalch equation, the pH of a weak acid solution is determined by A) ratio of the concentration of the acid in solution to the concentration of the base. B)ratio of the concentration of the base in solution to the concentration of the acid. C) the dissociation constant of bicarbonate. D)All of these answers are correct.
B
How do changes in muscle pH affect exercise performance? A) Increases in hydrogen ion concentrations in the muscle increases the ability to produce ATP by activating key enzymes involved in both glycolysis and aerobic production of ATP B) Hydrogen ions compete with calcium ions for binding sites on troponin, thereby hindering the contractile process C) Hydrogen ions impair breathing and limit the ability to move oxygen in/out of the lungs D) None of these answers is correct
B
Studies reveal that exercise training improves muscle buffering capacity. Which of the following exercise-induced changes is NOT responsible for training-induced improvements in muscle buffering capacity? A) increased levels of carnosine in muscle fibers B) increased muscle levels of citrate synthase C) increased content of hydrogen ion transporters D. None of these answers is correct
B
Sympatholysis refers to A) local inhibition of parasympathetic-induced vasoconstriction. B) local inhibition of sympathetic-induced vasoconstriction. C) increased parasympathetic-induced vasodilation. D) increased sympathetic-induced vasodilation
B
The central chemoreceptors that influence the control of breathing respond to changes in the A) H+ of mixed venous blood. B) PCO2 and H+ of cerebral spinal fluid. C) PO2, pH, and PCO2 of arterial blood. D) PCO2 and H+ of mixed venous blood.
B
Which of the following factors has the greatest influence on blood flow to a skeletal muscle during exercise? A) arterial pressure B) diameter of the arterial blood vessels leading to the muscle C) number of capillaries surrounding the muscle D) the viscosity of the blood
B
Which of the following is true of the pH of arterial blood? A) The normal pH is 7.0. B) A pH of 7.0 would be considered acidosis. C) A pH of 7.0 would be considered alkalosis. D)None of these answers is true.
B
Which of the following most accurately describes changes in autonomic control of heart rate during incremental exercise (from rest to VO2 max)? A) PNS outflow is followed by SNS withdrawal B) PNS withdrawal is followed by SNS outflow C) PNS and SNS outflow D) PNS and SNS withdrawal
B
According to the Fick equation, if cardiac output doubles during exercise and the arterial-mixed venous oxygen difference remains constant, body oxygen consumption would A) remain constant B) decrease by 50% C) increase by 100% D) none
C
An increase in blood levels of carbon dioxide results in a decrease in blood pH because an increase in PCO2 A) decreases H+ ion levels in the plasma. B) promotes an increase in lactic acid production in the muscle. C)reacts with water to form carbonic acid, which dissociates to release H+.
C
During exercise, the time spent in diastole and systole A) remains unchanged. B) is decreased equally. C) is decreased, with the greatest decrease occurring in diastole. D) is increased, with the greatest increase occurring in diastole.
C
In order to meet the increased oxygen demands of muscle during exercise, two major adjustments in blood flow must be made: a. an increase in HR and blood pressure .b. an increase in brain blood flow and blood flow to the skin. c. an increase in cardiac output and a redistribution of blood flow from inactive tissues to skeletal muscles. d. an increase in muscle blood flow and an increase in blood flow to the liver
C
Which of the following statements about heart rate variability (HRV) is NOT true? A) HRV refers to the time interval between heart beats. B) Epidemiological studies suggest that a low HRV is an excellent predictor of mortality in some patient populations. C) HRV decreases in response to regular aerobic exercise training. D) HRV is influenced by the balance between the parasympathetic nervous system and the sympathetic nervous system.
C
The exercise-induced hypoxemia that occurs in elite endurance athletes during heavy exercise is likely due to A) chronic obstructive lung disease. B) impaired alveolar ventilation resulting in hypoventilation. C) asthma D) a diffusion limitation secondary to a rapid red blood cell transit time.
D
The metabolic demand of the heart can be estimated by A) the rate-pressure product. B) the double product. C)multiplying heart rate by systolic blood pressure. D) All of these
D
The primary drive to increase ventilation during exercise is due to A) input from peripheral chemoreceptors. B) input from central chemoreceptors. C) input from skeletal muscle mechanoreceptors. D)none of these answers is correct.
D
Which of the following statements about a buffer is correct? A) a buffer resists pH change B) a buffer removes hydrogen ions from solution C) buffers often consist of a weak acid and its conjugate base D) All of these answers are correct
D
Which of the following conditions and/or diseases can result in metabolic acidosis or alkalosis? A) Uncontrolled diabetes B) Kidney diseases that result in a loss of acids C) Vomiting D)All of these are correct
D
Which of the following events are not primary sources of hydrogen ions during rigorous exercise? A) ATP breakdown and release of hydrogen ions B) Increased production of lactic acid C) Aerobic metabolism of glucose resulting in the production of carbon dioxide and subsequently, carbonic acid D) Production of 3-phosphoglucose during glycolysis
D
Which of the following events occurs during exercise at work rates above 60-80% VO2 max? A) a decrease in plasma bicarbonate concentration B) an increase in blood lactic acid concentration C) a decrease in blood pH D) All of these answers are correct
D
Which of the following factors contribute to "fine-tuning" of cardiovascular control during exercise? A)muscle chemoreceptors B)baroreceptorsmuscle C) mechanoreceptors D)All of these are correct
D
Which of the following represents the correct order of events of the flow of blood after it leaves the left ventricle and before it returns to the right atrium? A) Blood flows through the aorta, oxygen moves out of the capillaries, blood flows though veins, blood enters the venules. B) Blood flows through the venules, blood flows through the veins, oxygen moves out of the capillaries, blood enters the aorta. C) Oxygen moves out of the capillaries, blood flows through the aorta, blood flows through the venules, blood enters the veins. D) Blood flows through the aorta, oxygen moves out of the capillaries, blood flows through the venules, blood enters the veins.
D
Which of the following statements about hemoglobin's buffering capacity are true? A) Hemoglobin has six times the buffering capacity of plasma proteins because of it's concentration. B) Oxyhemoglobin is a better buffer than deoxyhemoglobin. C) Deoxyhemoglobin is a better buffer than oxyhemoglobin. D) Both Hemoglobin has six times the buffering capacity of plasma proteins because of it's concentration and Deoxyhemoglobin is a better buffer than oxyhemoglobin are correct.
D
Which of the following statements about skeletal muscle buffer systems is correct? A) Only one transporter exists (i.e., sodium-hydrogen exchanger) to move hydrogen ions across the sarcolemma B) Two monocarboxylate transporters exist in human skeletal muscle fibers C) High intensity exercise training has been reported to improve muscle buffer capacity by increasing both carnosine and hydrogen ion transporters in skeletal muscle D) Both Two monocarboxylate transporters exist in human skeletal muscle fibers and High intensity exercise training has been reported to improve muscle buffer capacity by increasing both carnosine and hydrogen ion transporters in skeletal muscle are correct
D
Which of the following statements are true about the changes in ventilatory patterns during exercise? A) Changes in breathing patterns during exercise are important to ensure that optimal mechanics of breathing are realized during exercise B) Changes in breathing patterns during exercise are designed to reduce the risk of respiratory muscle fatigue C) Increasing tidal volume during exercise ensures that dead space ventilation remains small D) all correct
D
Which of the following transporters in skeletal muscles are responsible for moving hydrogen ions across the sarcolemma? A)sodium-hydrogen exchanger B) monocarboxylate C) transporterNA/K transporter D) Both sodium-hydrogen exchanger and monocarboxylate transporter are correct
D
The fact that an increase in end-diastolic ventricular volume increases the stroke volume of the heart is an illustration of the
Frank-Starling law of the heart
An increase in alveolar ventilation (at rest) resulting in hyperventilation will reduce arterial ______ and increase ______.
PCO2 pH
Atrial repolarization occurs during which phase of the cardiac cycle as observed on an ECG?
QRS complex
In healthy and untrained subjects, the alinear rise in minute ventilation observed during incremental exercise (i.e., ventilatory threshold) could be due to
a decrease in arterial pH
molecules that release hydrogen ions (H+)
acids
Contraction of the rectus abdominis muscles would result in
active expiration
The volume of gas that reaches the gas-exchange zone of the lung is termed
alveolar ventilation
A decline in arterial PO2 to 70 mm Hg or below would likely result in
an increase in alveolar ventilation.
The ability of histidine to buffer hydrogen ions is because histidine contains
an ionizable group.
The respiratory system works in the regulation of acid-base balance by regulating
arterial pco2
Most of the increase in mean arterial blood pressure that occurs during dynamic (isotonic) incremental exercise is due to a. an increase in diastolic blood pressure. b. the increase in systolic blood pressure. c. both an increase in diastolic and systolic blood pressure. d. none of the above.
b
The greatest resistance to blood flow is in the a. veins. b. arterioles. c. aorta. d. capillaries.
b
Of the extracellular buffers, ________ contributes the most to the cell's buffering capacity?
bicarbonate
Gas exchange in the lungs occurs
both across approximately 300 million alveoli and in the respiratory zone are correct answers
Skeletal and cardiac muscle are similar in which of the following ways?
both muscles are composed of striated fibers containing actin and myosin
Autoregulation of local blood flow is due to a. the withdrawal of sympathetic impulses to arterioles. b. an increase in parasympathetic outflow to arterioles. c. local factors such as nitric oxide, prostaglandins, and adenosine. d. an increase in sympathetic impulses to arterioles c
c
Compared to the oxyhemoglobin dissociation curve, the myoglobin dissociation curve _______. A) is much steeper at PO2's below 20 mm Hg B) reaches a plateau at a much lower PO2 C) both is much steeper at PO2's below 20 mm Hg and reaches a plateau at a much lower PO2 are correct D) none of these answers is correct
c
Which of the following would not result in an increase in stroke volume during exercise? A) an increase in end diastolic volume due to increased venous return B) a decreased end systolic volume due to increased cardiac contractility C) an increase in afterload D) All of these would result in an increase in stroke volume
c
According to Fick's law of diffusion, the rate of diffusion of a gas across a tissue is directly proportional to the A) tissue area B) diffusion coefficient of the gas C) difference in partial pressure of the gas on the two sides of the tissue D) all corrext
d
In a healthy individual at sea level and at rest, which of following characteristics of arterial blood are correct? A) PO2 of approximately 100 mm Hg B) oxyhemoglobin saturation of 97-98%. C) oxygen content of 20 ml O2/100 ml blood. D) all of these answers are correct.
d
Which of the following statements about myoglobin are true? A) myoglobin binds oxygen. B) myoglobin shuttles oxygen from the cell membrane to the mitochondria. C)myoglobin exists in relatively large quantities in slow-twitch muscle fibers. D) all correct
d
Which of the following statements about pulmonary physiology is correct? A) The PO2 of inspired air at sea level is approximately 159 mm Hg. B) The percentage of CO2 in the air is 0.0003. C) The percentage of O2 in the air at sea level is the same as at high altitude. D) all are correct
d
The most important muscle of inspiration is/are the
diaphragm
______ is described as random movement of molecules from area of high concentration to an area of lower concentration
diffusion
The relationship between oxygen uptake, cardiac output, and the arterial-venous oxygen difference is described mathematically by the
fick equation
Small increases in arterial PCO2 have a ______________ effect on ventilation compared to small decreases in PO2.
greater
In the standing position, blood flow to the base of the lung is ______________ blood flow to the apex.
greater than
At a low PO2, myoglobin has _______________ affinity for O2 than hemoglobin.
higher
The central command theory of cardiovascular control proposes that initial signal to the cardiovascular control center comes from
higher brains center
Metabolic acidosis can result from the overproduction of ketoacids, which can occur
in uncontrolled diabetes
Withdrawal of parasympathetic influence on the heart results in
increase in HR
During a graded exercise test, the increase in ventilation during the transition from rest to moderate exercise is achieved by
increase in breathing frequency and tidal volume
Exercise-induced asthma could impair pulmonary gas exchange by
increasing airway resistance
Sodium bicarbonate has been ingested by athletes before competition in an effort to improve performance by
increasing blood buffering capacity
Electrical impulses are conducted between heart muscle cells by
intercalated discs
The first line of defense in protecting against pH change during exercise is
intracellular buffers within muscle fibers
Most of the O2 contained in the blood
is bound to hemoglobin as oxyhemoglobin.
The most common and strongest acid produced in skeletal muscle during heavy exercise is ________________ acid.
lactic
The relationship between cardiac output and metabolic rate is
linear and positively correlated
cardiovasular control center is located in the
medulla oblongata
An increase in PCO2 in the blood results in the formation of bicarbonate in the red blood cell. Because bicarbonate carries a negative charge (anion), the removal of negatively charged molecule from the red blood cell is required to prevent an electrochemical imbalance across the cell membrane. This problem is avoided by
movement of chloride molecules into the red blood cell.
muscle of the heart
myocardium
Acidosis can occur due to - a decrease in the H+ concentration. -a loss of acids from the blood. -an accumulation of bases in the blood. -none of these.
none
The carotid bodies are chemoreceptors that are sensitive to changes in arterial _______.
pH, PCO2, and PO2
the _____ is a measure of the relative concentration of hydrogen ions and hydroxyl ions in a solution.Correct
ph scale
The difference between systolic and diastolic blood pressure is called the
pulse pressure
At rest, voluntary hyperventilation can result in ___________ due to ____________.
respiratory alkalosis; decreased blood levels of carbon dioxide
Which of the following organs plays an important role in acid-base balance during exercise?
respiratory system
A significant increase in blood temperature (i.e. from 37ºC to 39ºC) would result in _____________ in the oxyhemoglobin dissociation curve.
rightward shift
Backflow of blood from the arteries into the heart ventricles is prevented by the
semilunar valves
in a healthy heart, the time spent in systole is generally _______ diastole.
shorter than
Studies reveal that ventilation drifts upward during constant-load submaximal exercise performed in a hot and humid environment. This is likely due to
significant increase in body temperature
in a pulmonary function test, a FEV1/FVC ratio of 0.60 is
suggestive of airway obstruction.
contraction phase of the heart
systole
The __________ represents ventricular repolarization during a recording of the electrical activity (i.e., ECG) of the heart.
t wave
A ventilation-perfusion (V/Q) ratio of 0.64 would indicate
that blood flow is higher than ventilation in this region of the lung.
The right shift in the oxyhemoglobin dissociation curve due to a rise in hydrogen ion concentration is called
the bohr effect
The amount of gas moved per breath is termed
tidal volume
Which of the following is NOT an important function of the pulmonary system? to cool the airways. to provide an interface for gas exchange between the external environment and the body. regulation of acid base balance during exercise. None of these answers is correct.
to cool the airways
A local increase in the nitric oxide concentration around arterioles would result in
vasodilation
mechanical process of moving air in and out of the lungs.
ventilation
