1. The Respiratory System: Modified by Dr. Par Mohammadian22
The Respiratory System: Modified by Dr. Par Mohammadian

2. The Respiratory System
Major function-respiration
Supply body with O2 for cellular respiration; dispose of CO2, a waste product of cellular respiration
Its four processes involve both respiratory and circulatory systems
Also functions in olfaction and speech

3. Processes of Respiration
Pulmonary ventilation (breathing)- movement of air into and out of lungs
External respiration-O2 and CO2 exchange between lungs and blood
Transport-O2 and CO2 in blood
Internal respiration-O2 and CO2 exchange between systemic blood vessels and tissues
Respiratory
system
Circulatory
system

4. Respiratory System: Functional Anatomy
Major organs
Nose, nasal cavity, and paranasal sinuses
Pharynx
Larynx
Trachea
Bronchi and their branches
Lungs and alveoli

5. Nasal cavity Oral cavity Nostril Pharynx Larynx Trachea Carina of
Figure The major respiratory organs in relation to surrounding structures.
Nasal cavity
Oral cavity
Nostril
Pharynx
Larynx
Trachea
Carina of
trachea
Left main
(primary)
bronchus
Right main
(primary)
bronchus
Left lung
Right
lung
Diaphragm
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6. Respiratory zone-site of gas exchange
Functional Anatomy
Respiratory zone-site of gas exchange
Microscopic structures-respiratory bronchioles, alveolar ducts, and alveoli
Conducting zone-conduits to gas exchange sites
Includes all other respiratory structures; cleanses, warms, humidifies air
Diaphragm and other respiratory muscles promote ventilation

7. The Nose Functions Provides an airway for respiration
Moistens and warms entering air
Filters and cleans inspired air
Serves as resonating chamber for speech
Houses olfactory receptors

8. Figure 22.2a The external nose.
The Nose - Two regions:
external nose &
nasal cavity
External nose-root, bridge, dorsum nasi, and apex
Philtrum-shallow vertical groove inferior to apex
Nostrils (nares)-bounded laterally by alae
Epicranius,
frontal belly
Root and
bridge of nose
Dorsum nasi
Ala of nose
Apex of nose
Naris (nostril)
Surface anatomy

9. Figure 22.2b The external nose.
Frontal bone
Septal cartilage
Maxillary bone
(frontal process)
Nasal bone
Lateral process of
septal cartilage
Minor alar
cartilages
Dense fibrous
connective tissue
Major alar
cartilages
External skeletal framework

10. Nasal cavity: Divided by midline nasal septum
The Nose
Nasal cavity: Divided by midline nasal septum
Posterior nasal apertures (choanae=funnels) open into nasopharynx
Roof of the nose: ethmoid & sphenoid bones
Floor: hard (bone) & soft palates (muscle)
Nasal conchae: Increase mucosal area; Enhance air turbulence)
Vibrissae (hairs) filter coarse particles from inspired air

11. Nasal Cavity Olfactory mucosa contains olfactory epithelium
Respiratory mucosa
Pseudostratified ciliated columnar epithelium
Mucous and serous secretions contain lysozyme and defensins
Cilia move contaminated mucus posteriorly to throat
Inspired air warmed by plexuses of capillaries and veins
Sensory nerve endings trigger sneezing

12. Figure 22.3b The upper respiratory tract.
Cribriform plate
of ethmoid bone
Frontal sinus
Sphenoid sinus
Nasal cavity
Posterior nasal
aperture
Nasal conchae
(superior, middle
and inferior)
Nasopharynx
Pharyngeal tonsil
Nasal meatuses
(superior, middle,
and inferior- grooves)
Opening of
pharyngotympanic tube
Nasal vestibule
Uvula
Nostril
Hard palate
Soft palate
Tongue
Lingual tonsil
Hyoid bone

13. Functions of the Nasal Mucosa and Conchae
During inhalation, conchae and nasal mucosa
Filter, heat, and moisten air
During exhalation these structures
Reclaim heat and moisture

14. Pharynx (throat) Pharynx Nasopharynx Oropharynx Laryngopharynx
Muscular tube from base of skull to C6
Connects nasal cavity and mouth to larynx and esophagus
Composed of skeletal muscle
Three regions:
Pharynx
Nasopharynx
Oropharynx
Laryngopharynx
Passageway for food and air
Regions of the pharynx

15. Figure 22.3b The upper respiratory tract.
Pharyngeal tonsil (adenoids) on posterior wall (traps & destrys pathogens)
Pharyngotympanic (auditory) tubes drain and equalize pressure in middle ear
Uvula: prevents food from entering the nose
Nasopharynx
Pharyngeal tonsil
Opening of
pharyngotympanic tube
Uvula
Tongue
Isthmus of fauces-opening to oral cavity
Palatine tonsils-in lateral walls of fauces
Lingual tonsil-on posterior surface of tongue
Oropharynx
Palatine tonsil
Lingual tonsil
Isthmus of the
fauces
Hyoid bone
Laryngopharynx
Larynx
Extends to larynx, where continuous with esophagus
Epiglottis
Vestibular fold
Thyroid cartilage
Esophagus
Vocal fold
Cricoid cartilage
When eating and giggling, food comes out of our nose!
Trachea
Thyroid gland
Illustration

16. Larynx
Attaches to hyoid bone; opens into laryngopharynx; continuous with trachea
Functions
Provides patent airway
Routes air and food into proper channels
Voice production
Houses vocal folds
Larynx
Epiglottis
Vestibular fold
Thyroid cartilage
Esophagus
Vocal fold
Cricoid cartilage
Trachea
Thyroid gland

17. All hyaline cartilage except epiglottis
Figure 22.4a The larynx.
Epiglottis
Thyrohyoid
membrane
Body of hyoid bone
Thyroid cartilage
Laryngeal prominence
(Adam’s apple)
In men larger: due to testosterone)
Cricothyroid ligament
Cricoid cartilage
Cricotracheal ligament
Tracheal cartilages
All hyaline cartilage except epiglottis
Anterior superficial view

18. Corniculate cartilage
Figure 22.4b The larynx.
Epiglottis
Body of hyoid bone
Thyrohyoid
membrane
Thyrohyoid membrane
Cuneiform cartilage
Fatty pad
Vestibular fold
(false vocal cord)
Corniculate cartilage
Arytenoid cartilage
Thyroid cartilage
Arytenoid muscles
Vocal fold
(true vocal cord)
Cricoid cartilage
Cricothyroid ligament
Cricotracheal ligament
Tracheal cartilages
Sagittal view; anterior surface to the right
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19. Larynx (voice box) Vocal ligaments-deep to laryngeal mucosa
Form core of vocal folds (true vocal cords)
Glottis-opening between vocal folds
Folds vibrate to produce sound as air rushes up from lungs
Vestibular folds (false vocal cords)
Superior to vocal folds
No part in sound production
Help to close glottis during swallowing
Base of tongue
Epiglottis
Vestibular fold (false vocal cord)
Vocal fold (true vocal cord)
Glottis
Inner lining of trachea
Cuneiform cartilage
Corniculate cartilage
Vocal folds in closed position; closed glottis
Vocal folds in open position; open glottis

20. Windpipe–from larynx into mediastinum Wall composed of three layers
Trachea
Windpipe–from larynx into mediastinum
Wall composed of three layers
Mucosa-ciliated pseudostratified epithelium with goblet cells
Submucosa-connective tissue with seromucous glands
Adventitia-outermost layer made of connective tissue; encases C-shaped rings of hyaline cartilage

21. Trachea Trachealis Connects posterior parts of cartilage rings
Contracts during coughing to expel mucus
Carina
Spar of cartilage on last, expanded tracheal cartilage
Point where trachea branches into two main bronchi
Carina of
trachea

22. Figure 22.6a Tissue composition of the tracheal wall.
Posterior
Mucosa
Esophagus
Submucosa
Trachealis
muscle
Lumen of
trachea
Seromucous gland
in submucosa
Hyaline cartilage
Adventitia
Anterior
Cross section of the trachea
and esophagus

23. Bronchi and Subdivisions
Air passages undergo 23 orders of branching  bronchial (respiratory) tree
From tips of bronchial tree  conducting zone structures  respiratory zone structures
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24. Conducting Zone Structures
Trachea  right and left main (primary) bronchi
Each main bronchus enters hilum of one lung
Right main bronchus wider, shorter, more vertical than left
Each main bronchus branches into lobar (secondary) bronchi (three on right, two on left)
Each lobar bronchus supplies one lobe
Each lobar bronchus branches into segmental (tertiary) bronchi
Segmental bronchi divide repeatedly
Branches become smaller and smaller 
Bronchioles-less than 1 mm in diameter
Terminal bronchioles-smallest-less than 0.5 mm diameter

25. Figure 22.7 Conducting zone passages.
Trachea
Superior lobe
of left lung
Left main
(primary)
bronchus
Superior lobe
of right lung
Lobar (secondary)
bronchus
Segmental (tertiary)
bronchus
Middle lobe
of right lung
Inferior lobe
of right lung
Inferior lobe
of left lung
Left side longer; right wider traps a foreign object that has entered the passageway

26. Conducting Zone Structures
From bronchi through bronchioles, structural changes occur
Cartilage rings become irregular plates; in bronchioles elastic fibers replace cartilage
Epithelium changes from pseudostratified columnar to cuboidal; cilia and goblet cells become sparse
Relative amount of smooth muscle increases
Allows constriction

27. Respiratory Zone
Begins as terminal bronchioles  respiratory bronchioles  alveolar ducts  alveolar sacs
Alveolar sacs contain clusters of alveoli
~300 million alveoli make up most of lung volume
Sites of gas exchange
Alveoli
Alveolar duct
Respiratory bronchioles
Alveolar duct
Terminal
bronchiole
Alveolar
sac

28. Figure 22.8b Respiratory zone structures.
bronchiole
Alveolar
duct
Alveolar
pores
Alveoli
Alveolar
sac
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29. Alveolar and capillary walls and their fused basement membranes
Respiratory Membrane
Alveolar and capillary walls and their fused basement membranes
~0.5-µm-thick; gas exchange across membrane by simple diffusion
Alveolar walls
Single layer of squamous epithelium (type I alveolar cells)
Scattered cuboidal type II alveolar cells secrete surfactant and antimicrobial proteins

30. Figure 22.9a Alveoli and the respiratory membrane.
Terminal bronchiole
Respiratory bronchiole
Smooth
muscle
Scanning electron micrograph of pulmonary capillary
casts (70x)
Elastic
fibers
Alveolus
Capillaries
Diagrammatic view of capillary-alveoli relationships

31. Surrounded by fine elastic fibers and pulmonary capillaries
Alveoli
Surrounded by fine elastic fibers and pulmonary capillaries
Alveolar pores connect adjacent alveoli
Equalize air pressure throughout lung
Alveolar macrophages keep alveolar surfaces sterile
2 million dead macrophages/hour carried by cilia  throat  swallowed

32. Figure 22.9c Alveoli and the respiratory membrane.
Red blood
cell
Nucleus of type I
alveolar cell
Alveolar pores
Capillary
Capillary
Macrophage
Alveolus
Endothelial cell
nucleus
Alveolus
Alveolar
epithelium
Respiratory
membrane
Fused basement
membranes of
alveolar
epithelium and
capillary
endothelium
Alveoli
(gas-filled
air spaces)
Red blood
cell in
capillary
Type II
alveolar
cell
Type I
alveolar
cell
Capillary
endothelium
Detailed anatomy of the respiratory membrane
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33. Lungs
Occupy all thoracic cavity except mediastinum
Root-site of vascular and bronchial attachment to mediastinum
Costal surface-anterior, lateral, and posterior surfaces
Composed primarily of alveoli
Balance–stroma-elastic connective tissue  elasticity

34. Heart (in mediastinum) Anterior mediastinum Sternum Anterior
Figure 22.10c Anatomical relationships of organs in the thoracic cavity.
Esophagus
(in mediastinum)
Posterior
Vertebra
Root of lung
at hilum
• Left main
bronchus
Right lung
• Left pulmonary
artery
Parietal pleura
• Left pulmonary
vein
Visceral pleura
Left lung
Pleural cavity
Thoracic wall
Pulmonary trunk
Pericardial
membranes
Heart (in mediastinum)
Anterior mediastinum
Sternum
Anterior
Transverse section through the thorax, viewed from above. Lungs, pleural
membranes, and major organs in the mediastinum are shown.
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35. Apex-superior tip; deep to clavicle
Lungs
Apex-superior tip; deep to clavicle
Base-inferior surface; rests on diaphragm
Hilum-on mediastinal surface; site for entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves
Left lung smaller than right
Cardiac notch-concavity to accommodate the heart
Separated into superior and inferior lobes by oblique fissure

36. Lungs
Right lung
Superior, middle, inferior lobes separated by oblique and horizontal fissures
Bronchopulmonary segments (10 right lung, 8–10 left lung) separated by connective tissue septa
If diseased can be individually removed
Lobules-smallest subdivisions visible to naked eye; served by bronchioles and their branches

37. Anterior view. The lungs flank mediastinal structures laterally.
Figure 22.10a Anatomical relationships of organs in the thoracic cavity.
Intercostal muscle
Rib
Parietal pleura
Lung
Pleural cavity
Visceral pleura
Trachea
Thymus
Apex of lung
Left
superior lobe
Right superior lobe
Oblique
fissure
Horizontal fissure
Right middle lobe
Left inferior
lobe
Oblique fissure
Right inferior lobe
Heart
(in mediastinum)
Diaphragm
Cardiac notch
Base of lung
Anterior view. The lungs flank mediastinal structures laterally.

38. Photograph of medial view of the left lung.
Figure 22.10b Anatomical relationships of organs in the thoracic cavity.
Apex of lung
Pulmonary
artery
Left main
bronchus
Left
superior lobe
Oblique
fissure
Pulmonary
vein
Left inferior
lobe
Cardiac
impression
Hilum of lung
Oblique
fissure
Aortic
impression
Lobules
Photograph of medial view of the
left lung.

39. Figure 22.11 A cast of the bronchial tree (segments).
Right lung
Left lung
Right
superior
lobe (3
segments)
Left superior
lobe
(4 segments)
Right
middle
lobe (2
segments)
Right
inferior lobe
(5 segments)
Left inferior
lobe
(5 segments)

40. Pleurae Thin, double-layered serosa: Parietal pleura Visceral pleura
Covers the thoracic wall and superior face of the diaphragm
Continues around heart and between lungs
Visceral pleura
Covers the external lung surface
Divides the thoracic cavity into three chambers
The central mediastinum
Two lateral compartments, each containing a lung