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ANATOMY & PHYSIOLOGY II
Lecture #8: Respiratory Anatomy
I. Introduction:
A. "Respiration" refers to three related processes:
1. Ventilation - breathing
2. Gas exchange - in the lungs between air and blood, in the tissues between blood and tissue cells.
3. Oxygen utilization - by the tissues for aerobic metabolism.
B. External respiration - the exchange of gases (O2 and CO2) between air and blood in the lungs.
C. Internal respiration - exchange of gases between the blood and cells in the tissues.
D. Components - The respiratory system includes all the organs and structures through which air passes to reach
the small chambers (alveoli) within the lungs where external respiration occurs. Some of these structures
(the oral cavity and portions of the pharynx) are also part of the digestive system.
II. Conducting passages - structures which carry air to the alveoli of the lungs, but which do not participate in gaseous
exchange.
Upper respiratory tract - nose, pharynx, and larynx.
Lower respiratory tract - trachea, bronchial tree, and lungs.
A. Nose and nasal cavity
1. Nose - the external structure composed of bone and cartilage covered by skin, lined by a mucous membrane.
2. Nasal cavity - the internal passageway through which air passes.
Right & left nasal fossa – the chambers on either side of the nose separated by:
Nasal septum - central dividing wall formed from the perpendicular plate of the ethmoid bone (top) and
the vomer (bottom).
Palate - separates nasal cavity from oral cavity below. The hard palate is the anterior part made of
bone. The soft palate is the posterior part made of muscle and connective tissue.
3. Nares - openings of the nasal cavity
External nares (nostril) – the anterior opening that connects the nasal cavity to the outside.
Internal nares (choana) - the posterior opening that connects the nasal cavity to the nasopharynx.
4. Nasal conchae
Superior, middle, and inferior nasal conchae (turbinates) protrude into the nasal cavity from the lateral
walls, and divide the cavity into three passageways called meatuses.
Meatuses - passageways through the nasal cavity between the conchae. Named for conchae that forms
its roof (superior meatus is between the superior and middle nasal concha, etc.)
5. Mucous lining of nasal cavity
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Simple ciliated columnar epithelium - forms mucous membrane lining the interior of the nasal cavity
Highly vascular – this lining has many blood vessels running through it.
Purpose: warms air and allows membrane to heal quickly
.
Rhinitis - inflammation of the mucous membrane lining the nasal cavity.
6. Functions of the nose and nasal cavity:
a. Filters, warms, and moistens air
b. Sense of smell - olfactory receptors in the roof of the cavity enable us to sense odors.
c. Resonating chamber for speech
B. Paranasal sinuses
1. Location - in the frontal, maxillary, sphenoid, and ethmoid bones.
2. Structure - air -filled spaces lined with mucous membranes.
3. Paranasal ducts - carry mucus from these sinuses into the nasal cavity.
4. Functions - produce mucus; resonating chambers for speech.
To Do: Identify the following structures on the diagram. See p. 832.
a.
b.
c.
d.
Frontal sinus
Sphenoid sinus
Hard palate
Soft palate
e.
f.
g.
h.
Superior nasal concha
Middle nasal concha
Inferior nasal concha
External nares
i.
j.
k.
l.
Superior meatus
Middle meatus
Inferior meatus
Internal nares
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C. Pharynx
1. Location - extends from the base of the skull & runs posterior to nasal and oral cavities down to the
esophagus.
2. Structure - muscular tube about 5 inches long.
3. Three regions:
a. Nasopharynx - portion located behind nasal cavity.
b. Oropharynx - portion located behind oral cavity.
c. Laryngopharynx - portion located behind larynx.
4. Contains three sets of tonsils:
a. Pharyngeal tonsils – located in the nasopharynx.
b. Palatine tonsils – located in the oropharynx.
c. Lingual tonsils – located in the oropharynx at the base of the tongue.
5. Pharygotympanic (auditory or eustachian) tube travels from the middle ear and opens into the lateral
wall of the nasopharynx.
6. Pharynx connects to:
Nasal cavity at the internal nares (choana)
Oral cavity via the fauces
Larynx and the esophagus at inferior end
7. Functions – serves as a passageway for air from the nasal cavity to the larynx and for food from the oral
cavity to the esophagus.
To Do: Identify the following structures on the diagram. See p. 832.
a.
b.
c.
Nasopharynx
Oropharynx
Laryngopharynx
d.
e.
Pharyngeal tonsil
Palatine tonsil
f.
g.
Lingual tonsil
Pharygotympanic tube
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D. Larynx
1. Description - tubular structure through which air from the pharynx passes to reach the trachea.
2. Composed of nine cartilages (three single and three pairs) connected to each other by muscles and
ligaments.
a. Thyroid cartilage - largest, encloses most of front and sides. Forms the:
Laryngeal prominence (Adam's apple) – the anterior protrusion of the thyroid cartilage at top.
b. Cricoid cartilage - ring-shaped, forms bottom of anterior surface and most of posterior surface.
Connects to thyroid cartilage, arytenoid cartilages and trachea.
c. Epiglottis - spoon-shaped cartilage that forms a flap to close over the entrance of the larynx during
swallowing.
Function: prevents entry of food or liquid into larynx.
d. Paired cartilages: arytenoid, corniculate, and cuneiform cartilages
Location: in the posterior wall of the larynx.
- The arytenoids furnish the point of attachment for the vocal folds.
3. Vocal folds
a. Vestibular folds (false vocal cords) - folds of the lining that support the true vocal cords, but are
not used in sound production.
Ventricle - the indentation in the wall of the larynx between the vestibular fold and the true vocal cord.
b. Vocal folds (true vocal cords) - a pair of strong connective tissue bands that stretch across the open
center of the larynx from the thyroid cartilage to the arytenoid cartilages.
Function: vibrate to produce sound.
Rima glottidis – the space in the middle of the larynx between the right and left true vocal cords.
4. Functions of the larynx - prevents food and fluid from entering the trachea and serves in sound production
during speech.
To Do: Identify the following structures on the diagram. See p. 834.
a.
b.
Thyroid cartilage
Cricoid cartilage
c.
d.
Arytenoid cartilage
Epiglottis
e.
f.
Vestibular fold
Vocal fold
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E. Trachea
1. Structure - a cylindrical tube about 4 inches long and 1 inch in diameter, with a framework supported by 15
- 20 C-shaped pieces of cartilage that hold it open.
2. Location - anterior to the esophagus. Extends from the larynx to the:
Carina - where trachea divides into the two primary bronchi.
3. Lining - mucous membrane of pseudostratified ciliated columnar epithelium containing numerous goblet
cells. Mucus secreted by the goblet cells traps inhaled particles, which are then swept upwards out of
the respiratory tract by the cilia.
4. Functions - carries air to the bronchi and cleanses inhaled air of particulate matter.
F. Bronchial Tree
1. Right and left primary bronchi
Location - branch from the trachea at the level of the sternal angle (T5) and enter lungs at the hilus.
Shape - the right bronchus is shorter, wider, and more vertical than the left.
2. Secondary bronchi - formed when the primary bronchi divide, supply air to each lobe of the lungs.
Number - 3 in the right lung and 2 in the left lung
3. Tertiary (segmental) bronchi - form when secondary bronchi divide. These give off still smaller branches
called bronchioles.
To Do: Identify the following structures on the diagram. See p. 838.
a.
b.
Trachea
Carina
c.
d.
Right bronchus
Left bronchus
e.
f.
Secondary bronchus
Tertiary bronchus
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4. Structure of bronchi compared to bronchioles:
Bronchi - primary, secondary, and tertiary bronchi have cartilage rings like the trachea.
Bronchioles - have almost no cartilage in their walls. Instead they have smooth muscle, which can
constrict or dilate the air passageway.
5. Terminal bronchioles - the last part of the conducting zone.
* No gaseous exchange occurs in the structures listed above.
6. Respiratory bronchioles - branch from the terminal bronchioles. Their walls are 2-3 cells thick, but as their
name suggests, CO2 and O2 can diffuse across the walls of these structures.
7. Alveolar ducts - branch from the respiratory bronchioles. They are essentially open passages that allow air
to flow to a number of alveoli.
8. Alveolar sac - a cluster of alveoli at the end of each alveolar duct.
9. Function of bronchial tree - to carry air to the alveoli of the lungs
III. Alveoli, Lungs, and Pleura
A. Alveoli
1. Description - small air sacs where the vast majority of gaseous exchange actually occurs.
2. Structure - walls are composed of a single layer of simple squamous epithelium surrounded by a capillary
network.
3. Surfactant - a chemical which coats the inner surface to decrease surface tension of fluid, thus preventing
the sacs from collapsing.
4. Function - to allow O2 to diffuse into the blood and CO2 to diffuse out to the lungs (gaseous exchange).
To Do: Identify the following structures on the diagram. See p. 839.
a.
b.
Terminal bronchiole
Respiratory bronchiole
c.
d.
Alveolar duct (2 places)
Alveolar sac
e.
Alveoli
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B. Lungs
1. Shape and location - two cone-shaped structures located to the right and left of the mediastinum in the
thoracic cavity. The base sits on the diaphragm, and apex reaches up to a point just above the clavicles.
2. Include all the structures beyond the primary bronchi.
3. Hilus – the indentation on the medial surface of each lung where the following structures enter the lung:
1) bronchi
3) nerves
2) pulmonary arteries and veins
4) lymphatic vessels
- Together these form the root of the lung. The lungs are freely movable except at the root.
4. The lungs are divided into lobes, which are separated by fissures.
5. Right lung - shorter, broader, and has a greater volume than the left.
# Lobes = 3 (superior, middle, and inferior)
Horizontal fissure – between superior and middle lobe.
Oblique fissure – between middle and inferior lobe.
6. Left lung - taller and narrower than the right, because the heart takes up space on the left.
# Lobes = 2 (superior and inferior)
Oblique fissure – between superior and inferior lobe.
Cardiac notch - indentation on the medial surface of left lung where the apex of the heart fits.
7. Functions - allows gas exchange with blood; expansion and contraction of lung tissue allows
ventilation to occur.
To Do: Identify the following structures on the diagram. See p. 838.
a.
b.
c.
Superior lobe of right lung
Middle lobe of right lung
Inferior lobe of right lung
d.
e.
f.
Superior lobe of left lung
Inferior lobe of left lung
Oblique fissure of left lung
g.
h.
i.
Oblique fissure of right lung
Horizontal fissure
Cardiac notch
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C. Pleura
1. Structure - double-layered serous membrane surrounding the lungs.
Pleurisy - inflammation of the pleura.
2. Location - surrounds each lung.
Parietal pleura - lines the wall of the thorax.
Visceral pleura - firmly attached to the surface of the lung.
3. Pleural cavity - the potential space in between the parietal and visceral pleura. It contains a small amount of
serous fluid produced by the membranes.
4. Functions a. Lubricates surface of lung, allowing frictionless movement.
b. Sets up pressure differential needed for ventilation.
c. Compartmentalizes thorax to prevent spread of infection or loss of pressure due to a puncture.
To Do: Identify the following structures on the diagram. See p. 842.
a.
Parietal pleura
b.
Visceral pleura
c.
Pleural cavity
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Learning Objectives for Lecture #8: Respiratory Anatomy
After studying this material you should be able to:
1.
List the three processes involved in respiration and distinguish between internal and external respiration.
2.
List in order the structures that make up the conducting passages of the respiratory system and identify
those that are part of the upper respiratory tract and those that form the lower tract.
3.
Describe the location, structure and function of the nose, nasal cavity, and paranasal sinuses.
4.
Describe the location, structure and function of the pharynx, including the location of the tonsils, the
entrance to the pharyngotympanic tube, and the connections between the pharynx and other structures.
5.
Describe the location, structure and function of the larynx, as well as any special structural features,
including the cartilages, vocal and vestibular folds, ventricle, and the rima glottidis.
6.
Describe the location, structure and function of the trachea and its lining.
7.
List in order the structures that make up the bronchial tree, describe the composition of each, and identify
their function. Know in which parts of the tree exchange of gases can occur.
8.
Describe the structure and function of alveoli and explain the role of surfactant.
9.
Describe the location and shape of the lungs, list the structures they contain, and explain what the hilus
is.
10.
Describe each lung, identify the number of lobes present, and identify and special features present only in
one lung. List the functions of the lungs.
11.
Describe the location and structure of the pleura; distinguish between the parietal pleura, visceral pleura,
and pleural cavity; and describe the functions of the pleura. Explain what pleurisy is.
12.
Identify on diagrams all structures labeled in this handout.
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Lecture #8: Respiratory Anatomy – Answer Key
Page 2 - Identify the following structures on the diagram. See p. 832.
a.
b.
c.
d.
Frontal sinus
Sphenoid sinus
Hard palate
Soft palate
e.
f.
g.
h.
Superior nasal concha
Middle nasal concha
Inferior nasal concha
External nares
i.
j.
k.
l.
B
Superior meatus
Middle meatus
Inferior meatus
Internal nares
A
E
I
J
F
G
K
H
L
C
D
Page 3 - Identify the following structures on the diagram. See p. 832.
a.
b.
c.
Nasopharynx
Oropharynx
Laryngopharynx
d.
e.
Pharyngeal tonsil
Palatine tonsil
f.
g.
Lingual tonsil
Pharygotympanic tube
D
G
A
E
F
B
C
11
Page 4 - Identify the following structures on the diagram. See p. 834.
a.
b.
Thyroid cartilage
Cricoid cartilage
c.
d.
Arytenoid cartilage
Epiglottis
e.
f.
Vestibular fold
Vocal fold
D
E
C
A
B
F
Page 5 - Identify the following structures on the diagram. See p. 838.
a.
b.
Trachea
Carina
c.
d.
Right bronchus
Left bronchus
e.
f.
Secondary bronchus
Tertiary bronchus
A
C
D
B
E
F
Page 6 - Identify the following structures on the diagram. See p. 839.
a.
b.
Terminal bronchiole
Respiratory bronchiole
c.
d.
Alveolar duct (2 places)
Alveolar sac
C
B
e.
Alveoli
E
C
A
D
12
Page 7 - Identify the following structures on the diagram. See p. 838.
a.
b.
c.
Superior lobe of right lung
Middle lobe of right lung
Inferior lobe of right lung
d.
e.
f.
Superior lobe of left lung
Inferior lobe of left lung
Oblique fissure of left lung
g.
h.
i.
A
Oblique fissure of right lung
Horizontal fissure
Cardiac notch
D
H
I
B
G
F
C
E
Page 8 - Identify the following structures on the diagram. See p. 842.
a.
Parietal pleura
b.
Visceral pleura
c.
Pleural cavity
C
A
B