Lung Volumes and Capacities

An example of a spirogram is shown in figure 16.16, and the various lung volumes and capacities are defined in table 16.3. A lung capacity is equal to the sum of two or more lung volumes. During quiet breathing, for example, the amount of air expired in each breath is the tidal volume. The maximum amount of air that can be forcefully exhaled after a maximum inhalation is called the vital capacity, which is equal to the sum of the inspiratory reserve volume, tidal volume, and expiratory reserve

Expiratory Reserve Volume Lungs

■ Figure 16.15 The mechanics of pulmonary ventilation. Pressures (at sea level) are shown (a) before inspiration, (b) during inspiration, and (c) during expiration. During inspiration, the intrapulmonary pressure is lower than the atmospheric pressure, and during expiration it is greater than the atmospheric pressure.

Lung Volumes And Capacities

■ Figure 16.16 A spirogram showing lung volumes and capacities. A lung capacity is the sum of two or more lung volumes. The vital capacity, for example, is the sum of the tidal volume, the inspiratory reserve volume, and the expiratory reserve volume. Note that residual volume cannot be measured with a spirometer because it is air that cannot be exhaled. Therefore, the total lung capacity (the sum of the vital capacity and the residual volume) also cannot be measured with a spirometer.

Table 16.3 Terms Used to Describe Lung Volumes and Capacities

Term

Definition

Lung Volumes

The four nonoverlapping components of the total lung capacity

Tidal volume

The volume of gas inspired or expired in an unforced respiratory cycle

Inspiratory reserve volume

The maximum volume of gas that can be inspired during forced breathing in addition to tidal volume

Expiratory reserve volume

The maximum volume of gas that can be expired during forced breathing in addition to tidal volume

Residual volume

The volume of gas remaining in the lungs after a maximum expiration

Lung Capacities

Measurements that are the sum of two or more lung volumes

Total lung capacity

The total amount of gas in the lungs after a maximum inspiration

Vital capacity

The maximum amount of gas that can be expired after a maximum inspiration

Inspiratory capacity

The maximum amount of gas that can be inspired after a normal tidal expiration

Functional residual capacity

The amount of gas remaining in the lungs after a normal tidal expiration

Table 16.4 Ventilation Terminology

Term

Definition

Air spaces

Alveolar ducts, alveolar sacs, and alveoli

Airways

Structures that conduct air from the mouth and nose to the respiratory bronchioles

Alveolar ventilation

Removal and replacement of gas in alveoli; equal to the tidal volume minus the volume of dead space times the breathing rate

Anatomical dead space

Volume of the conducting airways to the zone where gas exchange occurs

Apnea

Cessation of breathing

Dyspnea

Unpleasant, subjective feeling of difficult or labored breathing

Eupnea

Normal, comfortable breathing at rest

Hyperventilation

Alveolar ventilation that is excessive in relation to metabolic rate; results in abnormally low alveolar CO2

Hypoventilation

Alveolar ventilation that is low in relation to metabolic rate; results in abnormally high alveolar CO2

Physiological dead space

Combination of anatomical dead space and underventilated or underperfused alveoli that do not contribute normally to blood gas exchange

Pneumothorax

Presence of gas in the intrapleural space (the space between the visceral and parietal pleurae) causing lung collapse

Torr

Unit of pressure nearly equal to the millimeter of mercury (760 mmHg = 760 torr)

volume (fig. 16.16). Multiplying the tidal volume at rest by the number of breaths per minute yields a total minute volume of about 6 L per minute. During exercise, the tidal volume and the number of breaths per minute increase to produce a total minute volume as high as 100 to 200 L per minute.

It should be noted that not all of the inspired volume reaches the alveoli with each breath. As fresh air is inhaled, it is mixed with air in the anatomical dead space (table 16.4). This dead space comprises the conducting zone of the respiratory system— nose, mouth, larynx, trachea, bronchi, and bronchioles—where no gas exchange occurs. Air within the anatomical dead space has a lower oxygen concentration and a higher carbon dioxide concentration than the external air. Since the air in the dead space enters the alveoli first, the amount of fresh air reaching the alveoli with each breath is less than the tidal volume. But, since the volume of air in the dead space is an anatomical constant, the percentage of fresh air entering the alveoli is increased with increasing tidal volumes. For example, if the anatomical dead space is 150 ml and the tidal volume is 500 ml, the percentage of fresh air reaching the alveoli is 350/500 x 100% = 70%. If the tidal volume is increased to 2,000 ml, and the anatomical dead space is still 150 ml, the percentage of fresh air reaching the alveoli is increased to 1,850/2,000 x 100% = 93%. An increase in tidal volume can thus be a factor in the respiratory adaptations to exercise and high altitude.

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Responses

  • razanur
    What is expiratory reserve volume?
    7 years ago
  • nicholas
    How percentage of fresh air inspired with each breath?
    7 years ago
  • hamfast
    How much air is is typically inspired and expired per breath during quiet breathing?
    7 years ago
  • baldassarre
    What is the maximum tidal volume can reach?
    7 years ago
  • Selma
    What is the term for Amount of air that can be forcibly exhaled after a normal tidal expiration?
    7 years ago
  • SELASSIE
    Why is tidal volume less than vital capacity?
    7 years ago
  • nuguse
    Is vital capacity equal to total lung volume?
    7 years ago
  • Jewel Senn
    What is inspiratory reserve volume?
    7 years ago
  • Benjamin
    What are the different terms used to describe a humans lung capacity and volume?
    7 years ago
  • CHILIMANZAR BROWN
    What does atmospheric and intrapulmonary pressure have to do with ventilatin?
    7 years ago
  • dina
    Is the lung capacity of a human?
    7 years ago
  • PIIA-NOORA
    Is vital capacity greater than inspiratory capacity?
    7 years ago
  • mikaela
    Which lung volumes and capacities cannot be measured with spirometer?
    7 years ago
  • Sagramor
    What is expiratory reserve lung volume?
    7 years ago
  • kieron
    How do i calculate total lung capacity at different atmospheric pressures?
    7 years ago
  • manuela
    Does expiratory reserve volume decrease during exercise?
    7 years ago
  • nicole
    What Is Residual Volume in Human Lung Capacity?
    7 years ago
  • tomba
    What is pulmonary volume?
    7 years ago
  • shay
    Why is the vital capacity greater than tidal volume?
    7 years ago
  • Abeba
    What is the maximum amount of air expired after a maximum inspiration?
    7 years ago
  • JENS
    What is the total volume of air that can be exhaled after maximal inhalation called?
    7 years ago
  • Almaz
    What is the result of the inspiration capacity minus the tidal volume is equal to what lung volume?
    7 years ago
  • theobald
    What factor could cause an increase in the tidal volume in spirogram?
    7 years ago
  • deborah
    What is an example of a high vital capacity?
    7 years ago
  • Mattalic
    What are tidal volume and total lung capacity?
    7 years ago
  • mayme
    What is inspired reserved volume?
    7 years ago
  • Linda
    What capacities cannot be measured by spirogram?
    7 years ago
  • kacie
    Why is inspiratory reserve volume higher than expiratory reserve volume?
    7 years ago
  • sara
    What is the amount of air that can be forcefully exhaled after a tidal expiration is about?
    7 years ago
  • julia
    What area in the figure is the sum of the vital capacity and residual volume?
    7 years ago
  • eino
    How to make a spirogram of lung capacities?
    7 years ago
  • grant
    How are tidal volume and total lung capacity related?
    7 years ago
  • Girmay Massawa
    What percent of tidal volume is dead air?
    7 years ago
  • Damian
    Why intrapleural pressure is negative during inspiration?
    7 years ago
  • angelika
    How lungs are ventilated inspiration and expiration?
    6 years ago
  • basilio
    What is tidal volume during exercise?
    6 years ago
  • EMMIE
    What should the inspired volume of the lung be?
    6 years ago
  • lucas
    Where on the lung is expiration?
    6 years ago
  • Swen
    Is the pressure in the lungs lower than in the atmosphere?
    6 years ago
  • ismo
    How are tidal volume and total residual volume of the lungs related?
    6 years ago
  • marco
    What tidal volume percentage reaches the respiratory unit for gas exchage?
    6 years ago
  • ali afwerki
    How the lung volumes or capacities are altered?
    6 years ago
  • emilia
    Which phrase is used to describe the volume of air inspired and expired with a normal breath?
    6 years ago
  • BILBA
    What is the capacity of human lungs in the everest?
    6 years ago
  • janice
    What is the Sum of Vital capacity and residual volume called?
    6 years ago
  • belba
    What is the phase used to describe the volume of air that is inspired/expired?
    6 years ago
  • madeline
    What should lung volume be per liter?
    6 years ago
  • IVONE
    Which is bigger tidal volume or vital capacity?
    6 years ago
  • ritva
    What is total lung capacity minus the residual volume called?
    6 years ago
  • Jens
    What are the reserve capacities of the lungs?
    6 years ago
  • MATTHIAS MAYER
    What percentage of the tidal volume reaches the respiratory units and is available for gas exchange?
    6 years ago
  • paula
    What percent of tidal colume gets to the alveoli?
    5 years ago
  • Maria
    Is Inspiratory capacity is greater than inspiratory reserve volume?
    5 years ago
  • ernesto pinto
    What are the terms used to describe respiratory volume?
    5 years ago
  • HERIBALD
    What percent of tidal volume reaches respiratory unites?
    5 years ago
  • ambessa
    What is the respiration volume and capacity?
    5 years ago
  • mezan
    What is the volume of lung air per breath?
    5 years ago
  • urho
    What is the human inspiration capacity?
    5 years ago
  • Christina Millar
    How to make a numerical volume on spirogram?
    5 years ago
  • asfaha
    Why is inspiratory reserve volume greater than expiratory reserve volume?
    4 years ago
  • marvin
    What volume of each breath is used to ventilate dead space?
    4 years ago
  • anssi
    What volume of each breath is used to ventilate dead space in the respiratory tree?
    4 years ago
  • barry
    What volume is used to ventilate dead space in resp tree?
    4 years ago
  • prisca
    What volume of air is used to ventilate the dead space in the respiratory tree in an adult?
    4 years ago
  • Melilot
    What units are used for lung volumes and capacities?
    4 years ago
  • Yorda Petros
    What units are used for lungs volumes and capacities?
    3 years ago
  • futsum amanuel
    What is the average lung capacity of a human?
    3 years ago
  • angelica
    How much the vital capacity of human lung is equal to?
    3 years ago
  • rosamunda
    What is called as maximum amount of air exhaled from forceful inspiration?
    3 years ago
  • Jan-Erik
    What is the capacity in liters of adult lungs?
    3 years ago
  • sharon
    What lung volumes are components of the vital capacity?
    2 years ago
  • Einojuhani
    What area in the figure is the sum of the vital capacity and residual volume (Poin?
    2 years ago
  • freddie
    How much is the vital capacity of human lungs?
    2 years ago
  • Bell
    What is Lung volumes anatomy?
    2 years ago
  • Magnus
    Is residual volume lesser than tidal volume?
    2 years ago
  • Askalu
    What is the sum of the inspiratory reserve volume and the exipiratory reserve volume?
    2 years ago
  • lena herz
    How long volume is related to lung capacities?
    2 years ago
  • karolin
    What is tidal volume ans vital volume anatomy of lungs?
    2 years ago
  • Josefiina Kantee
    Is residual volume a component of vital capacity?
    2 years ago
  • Shukornia
    What percentage of each tidal volume is dead?
    2 years ago
  • Adelmo
    How to calculate the percentage of each tidal volume reaching functional alveoli?
    2 years ago
  • Dirk
    WHAT IS vital capacity, dead space volume and tidal volume?
    1 year ago
  • jeni fanning
    What is the term used for lung capacity?
    1 year ago
  • Marilena
    When air inspired reaches the alveoli it mixes with?
    1 year ago
  • islay forbes
    How much amount of air can be inspired or expired during normal breathing?
    1 year ago
  • everard
    What are the various volumes of lungs and the capacity during exercis?
    8 months ago
  • SALOMONE
    Is the capacity of the lungs equals the volume of air?
    8 months ago
  • crispus
    How much air is moving during quiet breathing?
    7 months ago
  • Heike
    IS THE MINUTE VOLUME EQUAL TO THE AMOUNT OF AIR AVAILABLE FOR GAS EXCHANGE IN?
    6 months ago
  • FRANK
    What are the examples of tidal volume?
    5 months ago
  • SERAFINO
    What are lung residual volumes in percentages?
    4 months ago
  • Riitta
    Which of the lung volume cannot be measured with a spirometer and why?
    3 months ago
  • Kirsty
    What area in the figure is the sum of the tidal volume and the inspiratory reserve volume?
    3 months ago
  • cain
    What is theoretical lung volume?
    28 days ago
  • Andrea Achen
    What best describes tidal volume of a lung?
    5 days ago

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