Exercise physiology Ch 10-12

The primary purpose to the pulmonary system is

B. to provide an interface for gas exchange

The term ventilation refers to the

C. mechanical process of moving are in and out of the lungs

The most important muscle of inspiration is/are the

A. diaphragm

The volume of gas that reaches the respiratory zone of the lungs is termed

C. alveolar ventilation

According to Fick's law of diffusion, the rate of diffusion for a gas is greater when the surface area for diffusion is large and the "driving pressure" between the two sides of tissue is high

A. true

In the standing position, blood flow to the base of the lung is __________ blood flow to the apex

C. greater than

Exercise-induces asthma would reduce airflow by

D. increasing airway resistance

Most of the O2 that is transported in the blood is in

B. the form of oxyhemoglobin

In general, because of blood hemoglobin concentration differences, males transport less oxygen per unit of blood volume than females

B. false

Research demonstrates that respiratory muscle fatigue does not occur during exercise

B. false

Myoglobin is a red pigment found in skeletal muscle that serves to

B. transport O2 from the cell membrane to the mitochondria

Carbon dioxide is transported in the blood principally as

C. bicarbonate

An increase in alveolar ventilation serves to lower arterial PCO2 and increase blood pH

A. true

Ventilation may drift upward during constant-load sub maximal exercise performed in a hot and humid environment due to

C. higher blood temperature

Exercise-induced hypoxemia that may occur in elite endurance athletes during heavy exercise is likely due to

D. a diffusion limitation secondary to a rapid red blood cell transit time

The respiratory control center is located in the

A. medulla oblongata

The carotid bodies are chemoreceptors that are sensitive to changes in arterial

B. pH, PCO2, and PO2

The ventilators central chemoreceptors respond to changes in the

B. pH of cerebral spinal fluid

A decrease in arterial PO2 below 70 mm Hg would likely result in

B. an increase in alveolar ventilation

Under normal conditions, the partial pressure of oxygen in the alveoli is

D. 100mmHg

The linear rise in ventilation observed during incremental exercise is thought to be principally due to

D. a decrease in arterial pH

Activation of rectus abdomens muscles would result in

C. active expiration

The ideal ventilations-perfusion ratio in the lung is

A. true

Under normal conditions, the characteristics of arterial blood include

D. all of the above

A by-product of anaerobic glycolysis in red blood cells that is thought to alter the O2-Hb dissociation curve is

B. 2-3 DPG

During exercise at sea level, young, healthy untrained subjects generally maintain expertise arterial PO2 within

B. 10-12 mm Hg of resting values

An increase in blood temperature and a decrease in blood pH would result in ________________ in the oxyhemoglobin curve

B. a leftward shift

At a low PO2, myoglobin has __________ affinity for O2 than hemoglobin

A. a higher

The intrapleural pressure is lower than the intrapulmonary pressure

A. true

The pulmonary system may limit VO2 max only in elite endurance athletes

B. false

During exercise, more oxygen is unloaded from hemoglobin to the tissues than at rest

A. true

Research indicates that nasal strips increase endurance performance

B. false

mitochondrial PO2 is __________ capillary PO2

B. less than

The amount of air inspired and expired at rest is called

A. tidal volume

In pulmonary function test, a FEV1/FVC ratio of 0.70 is

C. suggestive or airway obstruction

Which of the following is correct

A. the PO2 at sea level is 159 mmHg

Small changes in arterial PCO2 have a __________ effect on ventilation compared to small changes in PO2

A.greater

In response to exercise training, the normal lung

B. does not undergo measurable changes

Acids are defined as

B. molecules that release hydrogen ions (H+)

An example of a strong acid base is bicarbonate

A. true

Which of the following is true of the pH of arterial blood

B. a pH of 7.0 would be considered acidosis

Acidosis could be due to

D. none of the above

The most common and strongest organic acid produced in skeletal muscle during heavy exercise is ________ acid

B. lactic

An increase in the hydrogen ion concentration in contracting skeletal muscle can impair performance by hydrogen ions competing with calcium ions for binding sites on troponin

A. false

The first line of defense in protecting against pH change during exercise is

C. intracellular buffers

The most important of the blood buffers is

A. bicarbonate

The bicarbonate buffer system results in stimulation of ventilation

A. true

The respiratory system works in the regulation of acid-base balance by lowering the blood tension

B. CO2

One of the principal means by which the kidneys regulate acid-base balance is by increasing or decreasing the bicarbonate concentration of the blood

A. true

The prinicpal buffer against acidosis during exercise is intracellular phosphate groups

B. false

Muscle pH is generally

A. 0.4-0.6 pH units lower than blood pH

Sodium bicarbonate has been ingested by athletes in an attempt to improve performance by

A. increasing blood buffering capacity

Which of the following plays the most important role in acid-base balance during exercise

A. respiratory system

Which of the intracellular buffers contributes the most to the cell's buffering capacity?

intracellular proteins

Which of the following events occurs at approximately 50-60% VO2 max

D. all of the above

A lack of the enzyme carbonic anhydrase would affect the ability of the body to both buffer the blood and to transport CO2

a. true

Carbon dioxide is considered an acid because it

C. can react with water to form carbonic acid, which dissociates to release H+

Metabolic acidosis is a result of the overproduction of ketoacids, which can occur

B. in uncontrolled diabetes

Which of the following sports would have the greatest risk of acid-based distubance

C. 800-m run

Which of the following statements about body temperature homeostasis is correct

A. body temperature is a balance between heat loss and heat gain

during exercise, body temperature is regulated by making adjustments in the amount of heat that is lost

A. true

Heat production can be increased voluntarily through

D. exercise

The body's thermostat is located in the

C. hypothalamus

The principal means of heat loss at rest in a cool environment is via

A. radiation

The transfer of heat from the body into molecules of cooler objects in contact with its surface is called

b. conduction

In general, at high environmental temperatures, the most important variable determining heat loss by evaporation are the

D. all of the above

Which of the following could be a mechanism of heat gain in a hot environment

A. radiation

The evaporation of 1000 ml of sweat results in the loss of 1000 kcal of heat

B. false

An increase in core temperature results in

B. cutaneous vasdilation

In general, during exercise in a thermoneutral environment, the increase in core temperature is directly related to the exercise intensity

A. true

The primary adaptations that occur during heat acclimatization are

C. an increase plasma volume, earlier onset of sweating and a higher sweat rate

Hypothermia is defined as a large

B. decrease in core body temperature

Individuals with a high percentage of body fat have an advantage over lean individuals in tolerance to cold

A. true

Cold acclimatization results in an improved ability to sleep in a cold environment

A. true

Heat acclimatization occurs generally within

C. 7 to 14 days

Cold adaptation results in a reduction in the mean skin temperature at which shivering begins

A. true

A high percentage of body fat results in an increased ability to lose body heat during exercise

B. false

In response to a decrease in body temperature, the __________ initiates the release of norepinephrine, which increase the rate of cellular metabolism

B. posterior hypothalamus

Evaporation of one liter of sweat would result in the loss of ______ kcal of heat

D. 580

Training in a cool environment while wearing warm clothing promotes heat acclimatization

A. true

The most accurate way to measure core body temperature is with a tympanic thermometer

B. false

Which of the following is true of heat shock proteins

C. they help the body tolerate heat stress

Exercise in the heat is associated with accelerated fatigue due to

D. all of the above

The higher the relative humidity, the ___________ vapor pressure gradient between the skin and the environment

B. lower

During exercise ____________ of energy produces is released as heat

D. 70-80% kcal

Dehydration that result in a loss of 1-2% of body weight is sufficient to impair exercise performance

A. true

Compared to exercise in a cool environment, prolonged exercise in the heat

D. results in a more rapid onset of muscular fatigue