19  Respiratory System

Figure 19.1 The Respiratory System Organs.

19.1 Objectives

In this lab session you will be using models to study the respiratory system anatomy. You will also use a Spirometer to determine the volumes of the respiratory system.

19.2 By the end of this lesson, you will be able to:

  1. Identify the major respiratory system structures on a model, or diagram.
  2. Describe the functions of each structure within the respiratory system.
  3. Identify the following structures of the Upper Respiratory Tract:

19.3 Sagittal Head and Pharynx

  • Nostril

  • Nasal cavity

  • Conchae superior, middle, inferior

  • Meatus superior, middle, inferior Hard palate

  • Soft palate

  • Uvula

  • Tongue

  • Frontal sinus

  • Sphenoidal sinus

  • Palatine tonsil

  • Pharynx

    • Nasopharynx
      • Oropharynx
      • Laryngopharynx

  • Hyoid bone

  • Larynx

    • Glottis
    • Epiglottis

  • Esophagus

  • Trachea

19.4 Identify the following structures of the Larynx:

  • Hyoid bone

  • Thyroid cartilage

  • Cricoid cartilage

  • Epiglottis

  • Arytenoid cartilages

  • Tracheal cartilages

  • Glottis (space)

  • Vestibular folds (false vocal cords)

  • Vocal folds (true vocal cords)

19.5 Identify the following structures of the Lower Respiratory Tract: Lower Respiratory Tract

  • Trachea

  • Primary (main) bronchus

  • Secondary (lobar) bronchus

  • Tertiary (segmental) bronchus

  • Bronchiole

  • Alveolar duct

  • Alveolar sac

  • Alveolus

  • Pleural cavity

  • Parietal & visceral pleura

  • Right lung (3 lobes)

  • Left lung (2 lobes)

  • Pulmonary arteries

  • Pulmonary veins

  • Diaphragm

19.6 Identify and describe the mechanics of ventilation.

  • Spirometry
  • Tidal volume
  • Vital capacity

19.7 Prelab Activities:

19.8 Prelab Activity 19.1

19.9 Define the following terms

19.10 Sagittal Head and Pharynx

  • Nostril ________________________________________________________
  • Nasal cavity ___________________________________________________
  • Conchae - superior, middle, inferior ________________________________
  • Meatus - superior, middle, inferior __________________________________
  • Hard palate ____________________________________________________
  • Soft palate ____________________________________________________
  • Uvula ________________________________________________________
  • Tongue _______________________________________________________
  • Frontal sinus ___________________________________________________
  • Sphenoidal sinus _______________________________________________
  • Palatine tonsil __________________________________________________
  • Nasopharynx __________________________________________________
  • Oropharynx ____________________________________________________
  • Laryngopharynx ________________________________________________
  • Hyoid bone ____________________________________________________
  • Epiglottis ______________________________________________________
  • Larynx________________________________________________________
  • Trachea ______________________________________________________
  • Esophagus ____________________________________________________
  • Larynx ________________________________________________________
  • Hyoid bone ____________________________________________________
  • Thyroid cartilage ________________________________________________
  • Cricoid cartilage ________________________________________________
  • Epiglottis ______________________________________________________
  • Arytenoid cartilages _____________________________________________
  • Tracheal cartilages ______________________________________________
  • Glottis (space) _________________________________________________
  • Vestibular folds (false vocal cords) __________________________________
  • Vocal folds (true vocal cords) ______________________________________

19.11 Lower Respiratory Tract

  • Trachea ______________________________________________________
  • Primary (main) bronchus _________________________________________
  • Secondary (lobar) bronchus _______________________________________
  • Tertiary (segmental) bronchus _____________________________________
  • Bronchiole _____________________________________________________
  • Alveolar duct ___________________________________________________
  • Alveolar sac ___________________________________________________
  • Alveolus_______________________________________________________
  • Pleural cavity __________________________________________________
  • Parietal & visceral pleura _________________________________________
  • Right lung (3 lobes) _____________________________________________
  • Left lung (2 lobes) ______________________________________________
  • Pulmonary arteries ______________________________________________
  • Pulmonary veins ________________________________________________
  • Diaphragm ____________________________________________________

19.12 Know the mechanics of ventilation

  • Spirometry ____________________________________________________
  • Tidal volume___________________________________________________
  • Vital capacity __________________________________________________

19.13 Prelab Activity 19.2

Identify and label the structures of the respiratory system.

Figure 19.2 The Respiratory System, Unlabeled.

1 4
2 5
3

19.14 Lab Activities

19.15 Organs and structures of the Respiratory system.

Figure 19.3 Complete Respiratory System.

19.16 Upper Respiratory Tract: Sagittal Head and Pharynx

  • Nostril
  • Nasal cavity
  • Conchae
    • superior, middle, inferior
  • Respiratory Meatuses
    • superior, middle, inferior
  • Hard palate
  • Soft palate
  • Uvula
  • Tongue
  • Frontal sinus
  • Sphenoidal sinus
  • Palatine tonsil
  • Pharynx
    • Nasopharynx
    • Oropharynx
  • Laryngopharynx
  • Hyoid bone
  • Larynx
    • Glottis
    • Epiglottis
    • Thyroid cartilage
    • Cricoid cartilage
    • Arytenoid cartilages
    • Tracheal cartilages
    • Glottis (space)
    • Vestibular folds (false vocal cords)
    • Vocal folds (true vocal cords)
    • Trachea
    • Esophagus

19.17 Lab Activity 19.1

Break up into your assigned groups. Obtain a 3-D model of the mid-sagittal head model and the HubbardTM Scientific respiratory system model

  • Using the information from your text and the following figures (19.3 19.6) locate and identify the organs and structures of the upper and lower respiratory system.
  • Use some labelling tape to identify each vessel layer or structures. Have another group check your work for correctness. Have your instructor review your material as well.
  • Remember to take some pictures of your work to include in your study guide.

19.17.1 Upper and Lower Respiratory Systems

Figure 19.4 The Upper and Lower Respiratory Conducting Passages.

19.18 Upper Respiratory Tract

Figure 19.5 The Anatomy of the Nose, Pharynx, Mouth, and Larynx.

19.19 Divisions of the Pharynx

Figure 19.6 The Structure of the Pharynx and Larynx.

19.20 Lab Activity 19.2

Break up into your assigned groups. Obtain a 3-D model of the mid-sagittal head model and the HubbardTM Scientific respiratory system model

  • Using the information from your text and figure 19.7, locate and identify the organs and structures of the lower respiratory system.
  • Use some labelling tape to identify each vessel layer or structures. Have another group check your work for correctness. Have your instructor review your material as well.
  • Remember to take some pictures of your work to include in your study guide.

19.21 Lower Respiratory Tract

  • Trachea

  • Primary (main) bronchus

  • Secondary (lobar) bronchus

  • Tertiary (segmental) bronchus

  • Bronchiole

  • Alveolar duct

  • Alveolar sac

  • Alveolus

  • Pleural cavity

  • Parietal & visceral pleura

  • Right lung (3 lobes)

  • Left lung (2 lobes)

  • Pulmonary arteries

  • Pulmonary veins

  • Diaphragm

Figure 19.7 Gross Anatomy of the Lungs.

Working with your assigned groups, obtain a 3-D model of the larynx and/or the larynx with bronchial tree.

  • Using the information from your text and the following figures (19.8 & 19.9) locate and identify the organs and structures of the larynx and the bronchial tree.

  • Use some labelling tape to identify each vessel layer or structures. Have another group check your work for correctness. Have your instructor review your material as well.

  • Remember to take some pictures of your work to include in your study guide.

  • Larynx

    • Glottis
    • Epiglottis
    • Thyroid cartilage
    • Cricoid cartilage
    • Arytenoid cartilages
    • Tracheal cartilages
    • Glottis (space)

  • Vestibular folds (false vocal cords)

  • Vocal folds (true vocal cords)

  • Trachea

  • Esophagus

Figure 19.8 Posterior View of the Larynx.

Right lateral view

Figure 19.9 The Larynx, Anterior and Mid-Sagittal Views.

19.22 Respiratory physiology

Know and identify the stages of ventilation.

  • Spirometry
  • Tidal volume
  • Vital capacity

Figure 19.10 Typical Output from a Spirometer.

Figure 19.11 Buhl spirometer with mouthpieces.

19.23 Lab Activity 19.3 (Optional):

Measuring your lung volumes

19.23.1 Steps

  1. Initial steps: Setting up the spirometer.
  • Obtain a Buhl spirometer and a mouthpiece.
  • Place the mouthpiece on the tip of the port extending out of the spirometer’s body.
  • Exhale several times to practice how to use the spirometer correctly.
  1. Measuring tidal volume (TV):
  • Set the spirometer to “0.”
  • Standing , inhale normally and exhale several times to determine your normal breath pattern then when you have inhaled, exhale into the spirometer. Do not force your breath.
  • Since the spirometer begins to measure the exhaled volume at 1000ml you will have to repeat this procedure three times. After the third time record the total volume then divide that by three to obtain your average tidal volume.
  1. Measuring expiratory reserve volume (ERV).
  • Reset the dial to “0.”
  • Exhale and inhale several times using your tidal volume without measuring your exhalation.
  • Standing; at the bottom of the tidal volume, end of one cycle, place the mouthpiece of the spirometer in your mouth.
  • Exhale as much air as you can from your lungs.
  • Warning: do not take an extra-large inhalation before measuring this volume, it will skew your results.
  • Record the volume of this attempt.
  • You need to take two more measurements. It is recommended to take a break between each measurement.
  • Reset the spirometer to “0” before each measurement,
  • Record the next two attempts, add all three measurements then divide by three to obtain the average expiratory reserve volume.
  1. Measuring the vital capacity (VC):
  • Reset the spirometer to “0.”
  • Breath several times using your normal tidal volume.
  • Inhale as much as you can then exhale into the spirometer all of the air that you can. Breath out as much air as you can for as long as you are able.
  • Write own your measurement and reset the spirometer to “0.”
  • Take two more measurements, write down your measurements of your vital capacity after each exhalation then reset your dial to ‘0’ after each exhalation.
  1. Calculating the inspiratory reserve volume:
  • At this point you now have three measurements:
    • Tidal volume
    • Expiratory reserve volume
    • Vital capacity
  • To obtain your inspiratory reserve (IRV)
    • You will use the following formula Vital capacity (VC = Inspiratory capacity (IRV) = Tidal volume (TV) + expiratory reserve volume (ERV)
      • VC = IRV + TV + ERV.
    • To calculate your Inspiratory reserve volume, you need to modify the above calculation to:
      • IRV = VC (TV + ERV)
  1. After calculating your data, compare your values to your lab mates.
    1. How do your values compare to the other lab members?
    2. How do the female lung volumes compare with the male members?
    3. How would age affect the results?
    4. How might exercise, smoking or vaping affect your lung volumes?

19.24 Post Lab Activities

19.25 Test your understanding

19.26 Post Lab Activity 19.1

19.27 Labeling

Label the diagram of the respiratory system and the lung volumes using the terms previously listed in this chapter.

Figure 19.12 The Human Respiratory System, Numbered.

Table 19.1 Respiratory Anatomy Identifications

Number Structure
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

Table 19.1 Respiratory Anatomy Identifications continued

Number Structure
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

19.28 Volumes of the Lung.

Label this diagram.

Figure 19.13 Spirometer Output; enumerated.

Table 19.2 Respirometry Lung Volumes

Number Lung volume
1
2
3
4
5
6
7
8

19.29 Post Lab Activity 19.2

19.30 Identification

19.31 The larynx and trachea

Identify and label the structures that make up or are associated with the larynx and the trachea.

Figure 19.14 The Larynx.

19.32 Post Lab Activity 19.3: Crosswords:

Complete the following crossword puzzles.

Figure 19.15 Respiratory-1

19.32.1 Across

  • 2 The _____ is the region of the pharynx that only serves as an air passageway. (11)
  • 4 The ____ divides the nasal cavity into the right and left sides. (6)
  • 6 The nostrils are also known as the ____. (singular ____) (5,5)
  • 7 The superior boundary of the larynx is the _____ _____, above which is the laryngopharynx. Inferior to the larynx is the _____. (5,4,7)

19.32.2 Down

  • 1 Hair , mucus and cilia which line the nasal cavity prevent ___ and ___ from entering the lungs. (4,6)
  • 3 Air enters the nose and encounters the ____ _____, which creates turbulence thereby increasing the chances that airborne contaminants will contact the nasal mucosa rather than flowing directly into the lungs. (5,7)
  • 5 The casual phrase “voice box” refers to the ____. (6)

Figure 19.16 Respiratory-2

19.32.3 Across

  • 2 The top of the lung is _____; the bottom is the _____: (4,4)
  • 5 The _____ lung is divided into two lobes. (4)
  • 6 Serous Membranes which surround the lungs are called the _____. (6)
  • 7 _____ _____ is the process of gas exchange between the blood and the lungs. (8,11)
  • 8 The _____ lung is divided into three lobes. (5)

19.32.4 Down

  • 1 _____ _____ is the process of gas exchange between the fluids of the body and the cells. (8,11)
  • 3 Each lung is surrounded by its own _____ _____. (7,6)
  • 4 _____, which are located at the end of each alveolar duct, are chambers connected to several alveoli. (8,4)

Figure 19.17 Respiratory-3

19.32.5 Across

  • 4 Pulmonary function tests evaluate respiratory function using a(n) _____ to measure respiratory volumes and capacities. (10)

  • 5 The ____ ____ ____ is the maximum amount of air that can fill the lungs. (5,4,8)

19.32.6 Down

  • 1 The maximum amount of air that can be expelled after fully inhaling. (5,8)

  • 2 The ____ ____ is the amount of air inhaled during a normal, relaxed breath. In an average adult it is about _____ ml. (5,6,3)

  • 3 Each molecule of hemoglobin can carry (how many) molecules of oxygen. (4)

19.32.7 Keys to crossword puzzles

19.32.7.1 Respiratory-1

• Across: 2 Nasopharynx, 4 Septum, 6 Nares naris, 7 Hyoid bone trachea.

• Down: 1 Dust debris, 3 Nasal conchae, 5 Larynx.

19.32.7.2 Respiratory-2

• Across: 2 Apex base, 5 Left, 6 Pleura, 7 External respiration, 8 Right.

• Down: 1 Internal respiration, 3 Pleural cavity, 4 Alveolar sacs.

19.32.7.3 Respiratory-4

• Across: 4 Spirometer, 5 Total lung capacity.

• Down: 1 Vital capacity, 2 Tidal volume 500, 3 Four.

Chapter 19: Respiratory System Glossary

Terms Definitions
acclimatization process of adjustment that the respiratory system makes due to chronic exposure to high altitudes
acute mountain sickness (AMS) condition that occurs a result of acute exposure to high altitude due to a low partial pressure of oxygen
ala (plural = alae) small, flaring structure of a nostril that forms the lateral side of the nares
alar cartilage cartilage that supports the apex of the nose and helps shape the nares; it is connected to the septal cartilage and connective tissue of the alae
alveolar dead space air space within alveoli that are unable to participate in gas exchange
alveolar duct small tube that leads from the terminal bronchiole to the respiratory bronchiole and is the point of attachment for alveoli
alveolar macrophage immune system cell of the alveolus that removes debris and pathogens
alveolar pore opening that allows airflow between neighboring alveoli
alveolar sac cluster of alveoli
alveolus small, grape-like sac that performs gas exchange in the lungs
anatomical dead space air space present in the airway that never reaches the alveoli and therefore never participates in gas exchange
apex tip of the external nose
Arytenoid cartilage
apneustic center network of neurons within the pons that stimulate the neurons in the dorsal respiratory group; controls the depth of inspiration
atmospheric pressure amount of force that is exerted by gases in the air surrounding any given surface
Bohr effect relationship between blood pH and oxygen dissociation from hemoglobin
Boyle’s law relationship between volume and pressure as described by the formula: P1V1 = P2V2
bridge portion of the external nose that lies in the area of the nasal bones
bronchial bud structure in the developing embryo that forms when the laryngotracheal bud extends and branches to form two bulbous structures
bronchial tree collective name for the multiple branches of the bronchi and bronchioles of the respiratory system
bronchiole branch of bronchi that are 1 mm or less in diameter and terminate at alveolar sacs
bronchoconstriction decrease in the size of the bronchiole due to relaxation of the muscular wall
bronchodilation increase in the size of the bronchiole due to contraction of the muscular wall
bronchus tube connected to the trachea that branches into many subsidiaries and provides a passageway for air to enter and leave the lungs
carbaminohemoglobin bound form of hemoglobin and carbon dioxide
carbonic anhydrase (CA) enzyme that catalyzes the reaction that causes carbon dioxide and water to form carbonic acid
cardiac notch indentation on the surface of the left lung that allows space for the heart
central chemoreceptor one of the specialized receptors that are located in the brain that sense changes in hydrogen ion, oxygen, or carbon dioxide concentrations in the brain
chloride shift facilitated diffusion that exchanges bicarbonate (HCO3 - ) with chloride (Cl - ) ions
conducting zone region of the respiratory system that includes the organs and structures that provide passageways for air and are not directly involved in gas exchange
cricoid cartilage portion of the larynx composed of a ring of cartilage with a wide posterior region and a thinner anterior region; attached to the esophagus
Dalton’s law statement of the principle that a specific gas type in a mixture exerts its own pressure, as if that specific gas type was not part of a mixture of gases
dorsal respiratory group (DRG) region of the medulla oblongata that stimulates the contraction of the diaphragm and intercostal muscles to induce inspiration
dorsum nasi intermediate portion of the external nose that connects the bridge to the apex and is supported by the nasal bone
epiglottis leaf-shaped piece of elastic cartilage that is a portion of the larynx that swings to close the trachea during swallowing
esophagus
expiration (also, exhalation) process that causes the air to leave the lungs
expiratory reserve volume (ERV) amount of air that can be forcefully exhaled after a normal tidal exhalation
external nose region of the nose that is easily visible to others
external respiration gas exchange that occurs in the alveoli
fauces portion of the posterior oral cavity that connects the oral cavity to the oropharynx
Frontal sinus One of the four pairs of paranasal sinuses that are situated behind the brow ridges
fibroelastic membrane specialized membrane that connects the ends of the C-shape cartilage in the trachea; contains smooth muscle fibers
forced breathing (also, hyperpnea) expiration mode of breathing that occurs during exercise or by active thought that requires muscle contraction for both inspiration and expiration
foregut endoderm of the embryo towards the head region
functional residual capacity (FRC) sum of ERV and RV, which is the amount of air that remains in the lungs after a tidal expiration
glottis opening between the vocal folds through which air passes when producing speech
Haldane effect relationship between the partial pressure of oxygen and the affinity of hemoglobin for carbon dioxide
Henry’s law statement of the principle that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas
Hard palate The relatively hard, bony anterior portion of the palate.
hilum concave structure on the mediastinal surface of the lungs where blood vessels, lymphatic vessels, nerves, and a bronchus enter the lung
Hyoid bone A U-shaped bone at the base of the tongue that supports the tongue muscles.
hyperpnea increased rate and depth of ventilation due to an increase in oxygen demand that does not significantly alter blood oxygen or carbon dioxide levels
hyperventilation increased ventilation rate that leads to abnormally low blood carbon dioxide levels and high (alkaline) blood pH
inspiration (also, inhalation) process that causes air to enter the lungs
inspiratory capacity (IC) sum of the TV and IRV, which is the amount of air that can maximally be inhaled past a tidal expiration
inspiratory reserve volume (IRV) amount of air that enters the lungs due to deep inhalation past the tidal volume
internal respiration gas exchange that occurs at the level of body tissues
intra-alveolar pressure (intrapulmonary pressure) pressure of the air within the alveoli
intrapleural pressure pressure of the air within the pleural cavity
laryngeal prominence region where the two laminae of the thyroid cartilage join, forming a protrusion known as ‘Adam’s apple’
laryngopharynx portion of the pharynx bordered by the oropharynx superiorly and esophagus and trachea inferiorly; serves as a route for both air and food
larynx The part of the respiratory tract between the pharynx and the trachea, having walls of cartilage and muscle and containing the vocal cords enveloped in folds of mucous membrane.
laryngotracheal bud bud forms from the lung bud, has a tracheal end and bulbous bronchial buds at the distal end
larynx cartilaginous structure that produces the voice, prevents food and beverages from entering the trachea, and regulates the volume of air that enters and leaves the lungs
lingual tonsil lymphoid tissue located at the base of the tongue
lung organ of the respiratory system that performs gas exchange
lung bud median dome that forms from the endoderm of the foregut
Maxillary sinus Largest of the four paranasal sinuses, and drains into the middle meatus of the nose
meatus one of three recesses (superior, middle, and inferior) in the nasal cavity attached to the conchae that increase the surface area of the nasal cavity
naris (plural = nares) opening of the nostrils
nasal bone bone of the skull that lies under the root and bridge of the nose and is connected to the frontal and maxillary bones
Nasal cavity
nasal septum wall composed of bone and cartilage that separates the left and right nasal cavities
nasopharynx portion of the pharynx flanked by the conchae and oropharynx that serves as an airway
nostril Large, air-filled space above and behind the nose in the middle of the face
olfactory pit invaginated ectodermal tissue in the anterior portion of the head region of an embryo that will form the nasal cavity
oropharynx portion of the pharynx flanked by the nasopharynx, oral cavity, and laryngopharynx that is a passageway for both air and food
oxygen-hemoglobin dissociation curve graph that describes the relationship of partial pressure to the binding and disassociation of oxygen to and from heme
oxyhemoglobin (Hb- O2) bound form of hemoglobin and oxygen
palatine tonsil one of the paired structures composed of lymphoid tissue located anterior to the uvula at the roof of isthmus of the fauces
paranasal sinus one of the cavities within the skull that is connected to the conchae that serve to warm and humidify incoming air, produce mucus, and lighten the weight of the skull; consists of frontal, maxillary, sphenoidal, and ethmoidal sinuses
parietal pleura outermost layer of the pleura that connects to the thoracic wall, mediastinum, and diaphragm
partial pressure force exerted by each gas in a mixture of gases
peripheral chemoreceptor one of the specialized receptors located in the aortic arch and carotid arteries that sense changes in pH, carbon dioxide, or oxygen blood levels
pharyngeal tonsil structure composed of lymphoid tissue located in the nasopharynx
pharynx region of the conducting zone that forms a tube of skeletal muscle lined with respiratory epithelium; located between the nasal conchae and the esophagus and trachea
philtrum concave surface of the face that connects the apex of the nose to the top lip
pleural cavity space between the visceral and parietal pleurae
pleural fluid substance that acts as a lubricant for the visceral and parietal layers of the pleura during the movement of breathing
pneumotaxic center network of neurons within the pons that inhibit the activity of the neurons in the dorsal respiratory group; controls rate of breathing
pulmonary artery artery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli
Pulmonary veins the veins that transfer oxygenated blood from the lungs to the heart
pulmonary plexus network of autonomic nervous system fibers found near the hilum of the lung
pulmonary surfactant substance composed of phospholipids and proteins that reduces the surface tension of the alveoli; made by type II alveolar cells
pulmonary ventilation exchange of gases between the lungs and the atmosphere; breathing
quiet breathing (also, eupnea) mode of breathing that occurs at rest and does not require the cognitive thought of the individual
residual volume (RV) amount of air that remains in the lungs after maximum exhalation
respiratory bronchiole specific type of bronchiole that leads to alveolar sacs
respiratory cycle one sequence of inspiration and expiration
respiratory epithelium ciliated lining of much of the conducting zone that is specialized to remove debris and pathogens, and produce mucus
respiratory membrane alveolar and capillary wall together, which form an air-blood barrier that facilitates the simple diffusion of gases
respiratory rate total number of breaths taken each minute
respiratory volume varying amounts of air within the lung at a given time
respiratory zone includes structures of the respiratory system that are directly involved in gas exchange
root region of the external nose between the eyebrows
thoracic wall compliance ability of the thoracic wall to stretch while under pressure
thyroid cartilage largest piece of cartilage that makes up the larynx and consists of two laminae.
Soft palate
Sphenoid sinus a paired paranasal sinus occurring within the body of the sphenoid bone.
Thyroid cartilage the soft tissue constituting the back of the roof of the mouth.
tidal volume (TV) amount of air that normally enters the lungs during quiet breathing
tongue The fleshy, movable, muscular organ, attached in most vertebrates to the floor of the mouth, which is the principal organ of taste, an aid in chewing and swallowing, and, in humans, an important organ of speech.
total dead space sum of the anatomical dead space and alveolar dead space total dead space sum of the anatomical dead space and alveolar dead space
total lung capacity (TLC) total amount of air that can be held in the lungs; sum of TV, ERV, IRV, and RV
total pressure sum of all the partial pressures of a gaseous mixture
trachea tube composed of cartilaginous rings and supporting tissue that connects the lung bronchi and the larynx; provides a route for air to enter and exit the lung
trachealis muscle smooth muscle located in the fibroelastic membrane of the trachea
transpulmonary pressure pressure difference between the intrapleural and intra-alveolar pressures
true vocal cord (vocal folds) one of the pair of folded, white membranes that have a free inner edge that oscillates as air passes through to produce sound
type I alveolar cell squamous epithelial cells that are the major cell type in the alveolar wall; highly permeable to gases
type II alveolar cell cuboidal epithelial cells that are the minor cell type in the alveolar wall; secrete pulmonary surfactant
uvula a conic projection from the back edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers.
ventilation movement of air into and out of the lungs; consists of inspiration and expiration
ventral respiratory group (VRG) region of the medulla oblongata that stimulates the contraction of the accessory muscles involved in respiration to induce forced inspiration and expiration
vestibular fold part of the folded region of the glottis composed of mucous membrane; supports the epiglottis during swallowing
visceral pleura innermost layer of the pleura that is superficial to the lungs and extends into the lung fissures
vital capacity (VC) sum of TV, ERV, and IRV, which is all the volumes that participate in gas exchange