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