Chapter 10 Exercise Physiology
The ideal ventilation-to-perfusion ratio (V/Q) is _____ or slightly greater
1.0
Normal hemoglobin concentration for a healthy male and female is approximately _____, respectively, per liter of blood
150 grams and 130 grams
Identify a structure that is a part of the respiratory zone of the respiratory system.
Alveolar sacs
Match the types of primary peripheral chemoreceptors (in the left column) with their descriptions (in the right column).
Aortic bodies They are capable of sensing changes in blood levels of CO2 indirectly. Carotid bodies They are sensitive to increases in blood potassium levels.
A decrease in blood pH results in a right shift in the oxyhemoglobin curve and is called the
Bohr effect
Match the types of humoral chemoreceptor (in the left column) with their descriptions (in the right column).
Central chemoreceptors These are located in the medulla and are affected by changes in PCO2 and H+ of the cerebrospinal fluid. Peripheral chemoreceptors They are located in the aortic arch and at the bifurcation of the common carotid artery. They respond to changes in arterial H+ concentrations, PCO2, blood potassium levels, and arterial PO2.
The total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert independently. This law of partial pressure is referred to as
Dalton's law
Match the types of respiration (in the left column) with their definitions (in the right column)
Pulmonary respiration: It refers to ventilation (breathing) and the exchange of gases (O2 and CO2) in the lungs. Cellular respiration: It refers to O2 utilization and CO2 production by the tissues.
Diffusion limitations during intense exercise in elite athletes could occur due to a reduced amount of time that _____ spend in the pulmonary capillary.
RBCs
Identify a technique used to measure pulmonary volumes in which a subject is required to breathe into a device that is capable of measuring inspired and expired gas volumes.
Spirometry
Identify the areas in the brain stem in which the respiratory control center is located. (Check all that apply.)
The medulla oblongata The pons
Match the components of the respiratory control center (in the left column) with their descriptions (in the right column).
The preBotzinger complex (preBotC) The primary neural pacemaker responsible for inspiration The retrotrapezoid nucleus/parafacial respiratory group (RTN/pFRG) Controls active expiration
Identify a structure in the conducting zone of the human respiratory system
Trachea
Which of the following processes occur during the exchange of O2 and CO2 between the lung and blood? (Check all that apply.)
Ventilation Diffusion
Match the processes that occur during respiration (in the left column) with their descriptions (in the right column).
Ventilation It refers to the mechanical process of moving air into and out of the lungs. Diffusion It is the random movement of molecules from an area of high concentration to an area of lower concentration.
Bulk flow is the movement of molecules along a passageway due to
a pressure difference between the ends of the passageway
During exercise, increased heat production in the contracting muscle would promote
a right shift in the oxyhemoglobin dissociation curve
The pressure that each gas exerts independently can be calculated by multiplying the fractional composition of the gas by the
absolute pressure
The function of the respiratory zone is to
act as the site of gas exchange between the alveoli and blood
Neural input to the respiratory control center refers to _____ input.
afferent or efferent
Airflow through the pulmonary system is increased anytime there is a decrease in
airway resistance
The human respiratory system is composed of a group of passages that filter air and transport it into the lungs, where gas exchange occurs within tiny air sacs called
alveoli
A majority of the CO2, which is about 70%, in the blood is transported in the form of
bicarbonate
During prolonged submaximal exercise in a hot or humid environment, ventilation tends to drift upward due to an increase in
blood temperature
Although there is an increase in ventilation during prolonged submaximal exercise in a hot or humid environment, there is little change in PCO2. This suggests that the increase in ventilation is due to an increase in
breathing frequency and dead-space ventilation
Movement of air from the environment to the lungs is called pulmonary ventilation and occurs via a process known as
bulk flow
In order to transport CO2 in the blood, under high PCO2 conditions, CO2 combines with water to form carbonic acid. This reaction is catalyzed by the enzyme
carbonic anhydrase
The _____ are responsible for the increase in VE following exposure to low PO2
carotid bodies
The most important variable contributing to airway resistance is the
diameter of the airway
The major muscle of inspiration, which causes an increase in the volume of the chest, is the
diaphragm
True or false: Arterial PO2 decreases and arterial PCO2 tends to increase slightly in the transition from rest to steady-state exercise. This observation suggests that the increase in metabolism at the beginning of exercise is not as rapid as the increase in alveolar ventilation.
false
True or false: In the context of the oxygen-hemoglobin dissociation curve, loading and unloading are irreversible reactions
false
True or false: Similar to the muscular-skeletal system and the cardiovascular system, the lungs also undergo adaptive changes in response to regular endurance exercise.
false
True or false: When blood flow to the alveolus does not adequately match ventilation, gas exchange occurs rapidly
false
The conducting zone of the respiratory system not only serves as a passageway for air, but also functions to
filter, warm, and humidify the air
During inspiration, when the diaphragm contracts, it
forces the abdominal contents downward and forward
Myoglobin is capable of discharging its O2 at very low PO2 values, because it has a
greater affinity for O2 than hemoglobin
Approximately 99% of the O2 transported in the blood is chemically bound to
hemoglobin
Growing evidence suggests that the pulmonary system may limit exercise performance during _____ exercise at sea level
high-intensity
Fine-tuning of breathing to match the metabolic rate is performed by input from
humoral chemoreceptors
A secondary factor that might contribute to ventilatory control during heavy exercise is a(n)
increase in blood potassium levels
The rise in blood lactate that occurs during incremental exercise may be the cause of the alinear rise in the ventilatory threshold, because the carotid bodies that increase the threshold can be stimulated by a(n)
increase in hydrogen ion levels
At the beginning of constant-load submaximal exercise, there is an initial rapid
increase in ventilation
At a constant pH, the affinity of hemoglobin for O2 is
inversely related to blood temperature
In the context of the oxygen-hemoglobin dissociation curve, the combination of O2 with hemoglobin in the lung (alveolar capillaries) is often called
loading
When compared to the systemic circuit, the pulmonary circuit has a
lower pressure
Motor neuron activity, is directly controlled by the respiratory control center in the
medulla oblongata
Input for the regulation of ventilation can come in the form of efferent input from the
motor cortex
Oxygen transport in muscle is carried out by the oxygen-binding protein called
myoglobin
Input to the respiratory control center can be classified into
neural and humoral
The "initial" drive to increase ventilation during exercise is due to
neural input from higher brain centers
Both the right and the left lungs are enclosed by a set of membranes called
pleura
Carotid bodies also promote increase in ventilation as a response to increases in blood levels of
potassium
The primary purpose of the respiratory system is to
provide a means of gas exchange between the external environment and the body
During active expiration, the muscles in the abdominal wall work to
push the diaphragm upward
The pulmonary circuit and the systemic circuit of blood flow are similar in that both circuits have equal
rates of blood flow
At rest, the process of expiration
requires no muscular effort
Research confirms that during high-intensity exercise,
respiratory muscle fatigue does occur
Input for the regulation of ventilation can come in the form of afferent pathways from mechanoreceptors in the _____ of the heart relative to increases in cardiac output.
right ventricle
Contraction and relaxation of the respiratory muscles are directly controlled by
somatic motor neurons in the spinal cord
The technique used for measuring pulmonary volumes in the human body is known as
spirometry
The adaptability of pulmonary structures to endurance training is substantially less than the muscular-skeletal system and the cardiovascular system because the
structural capacity of the normal lung is overbuilt
The amount of gas moved per breath is called
tidal volume
The amount of gas ventilated per minute is the product of the frequency of breathing and the
tidal volume
True or false: The ventilatory threshold (Tvent) occurs in both trained athletes and untrained students
true
Exercise-induced hypoxemia in elite athletes is likely to occur because of
ventilation-perfusion mismatch and diffusion limitations
During an incremental exercise test, ventilation increases as a linear function of oxygen uptake up to 50% to 70% of O2 max, where ventilation begins to rise exponentially. This VE "inflection point" has been called the
ventilatory threshold
In the context of the oxygen transport in blood, the strength of the bond between O2 and hemoglobin is
weakened by a decrease in blood pH