Lab Exercise 24
Anatomy of the Respiratory System
Portland Community College
BI 233
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Upper & Lower Respiratory
System
 Upper Respiratory
System




Nose
Nasal cavity
Paranasal sinuses
Pharynx
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Respiratory system
 Lower Respiratory
System




Larynx
Trachea
Bronchi
Lungs
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Nasal bones
• Frontal and nasal bones
for the nasal bridge and
processes of the maxillae
make up the lateral walls.
• Nasal septum divides the
nasal cavity into right and
left halves formed by
vomer and perpendicular
plate of the ethmoid
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Uvula
• During swallowing,
the soft palate elevates
and the uvula closes
off the internal nares,
preventing food or
fluids from entering
the nasal cavity.
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Nasal Cavity
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Nasal Cavity
Opening of
Auditory
Tube
Superior
Middle &
Inferior
Turbinates
External
Nares
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Nasal Cavity
 The nasal epithelium covering the conchae
serves to cleanse, warm and humidify the air
• Nasal conchae increase the surface areas
for the mucus epithelium
 The olfactory epithelium in the upper medial part
of the nasal cavity is involved in the sense of
smell.
 The nasal cavity serves as a resonating chamber
as well as an avenue for escaping air.
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Nasal Turbinates or Conchae
• Ciliated pseudostratified
columnar epithelium with
.
goblet cells pushes trapped
dust toward the back of the
throat to be swallowed.
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Sinuses
All the sinuses are
continuous with the nasal
cavity are lined by mucous
membrane.
Mucous secretions drain
into the nasal cavities.
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Pharynx
• Connects the nasal and oral cavities to the
larynx and esophagus
• Anatomically divided into 3 sections:
• Nasopharynx
• Oropharynx
• Laryngopharynx
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(pseudostratified
epithelium)
(stratified squamous
epithelium)
(stratified squamous
epithelium) 13
Tonsils
Pharyngeal
Tonsils
(Adenoids)
Palatine
Tonsils
Lingual
Tonsils
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Tonsils
Pharyngeal
tonsils
• Tonsils: lymphoid tissue.
Palatine
tonsils
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Larynx: aka Voice Box
• Made of 9 pieces of cartilage, the most important
are:
• Thyroid cartilage (Adam’s Apple)
• Thyrohyoid membrane
• Cricoid Cartilage
• Cricothroid ligament
• Epiglottis
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Hyoid Bone
Larynx
Epiglottis
Thyrohyoid
Membrane
Thyroid Cartilage
Cricoid Cartilage
Cricothyroid
Ligament
Tracheal Cartilage
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Inside the Larynx
• Vestibular Folds:
• Also called false vocal cords, ventricular band of
larynx, ventricular folds, and upper folds
• Vocal Cords, or vocal folds
• Lower, “true” vocal cords
• Attach to the arytenoid cartilages by the vocal
ligaments (internal)
• Glottis: The vocal cords and the space (rima
glottidis) between them.
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Inside the Larynx
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Inside the Larynx
Rima Glottis
True Vocal
Cords
Corniculate
cartilage
Cuneiform
cartilage
Glottis
Epiglottis
Tongue
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Glottis: True cords plus opening
Rima Glottis: The opening
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Larynx
Airways
Trachea
The carina is the last
cartilage which
separates the
entrances to the left
and right primary
bronchi
Right Mainstem
Bronchi
Left Mainstem
Bronchi
Secondary
Bronchi
Carina
Secondary
Bronchi
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Bronchi
• The carina of the last tracheal cartilage marks
the end of the trachea and the beginning of the
right and left bronchi
• Left main stem bronchus
• Right main stem bronchus
• Bronchi subdivide into secondary bronchi, each
supplying a lobe of the lungs
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Respiratory Tree
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Branching of Bronchial Tree
Trachea
Primary Bronchi
Secondary Bronchi
Tertiary Bronchi
Bronchioles
Terminal/Respiratory Bronchioles
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Lungs
•
•
•
•
Apex: the part under the clavicle
Base: the part touching the diaphragm
Costal Surface: the part touching the ribs
Hilus: indentation containing pulmonary and systemic
blood vessels
• Left Lung has 2 lobes and a cardiac notch
• Left upper lobe
• Left lower lobe
• Right Lung has 3 lobes
• Right upper lobe, middle lobe, lower lobe
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Apex
Lungs
LUL
RUL
Hilus
RML
LLL
RLL
Base
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Lungs: Medial View
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Lung Lobes
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Pleura
• Pleura is the double-layered sac of serous membrane
• Parietal Pleura is the outer layer and is attached to the
thoracic walls
• Visceral Pleura is the inner layer covering the lung tissue
• The layers are only touching, they are not fused
together
• The potential space is called the pleural cavity
• There is serous fluid between the layers which allows them to
slide against each other during breathing
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Pleural cavity is in
between the two
layers
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Mediastinum
• The area between the
lungs.
• Posterior to the
sternum
• Anterior to the
vertebrae
• Contains the heart,
great vessels,
esophagus and thymus
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Trachea Histology
• Composed of three layers
• Mucosa: made up of goblet cells and ciliated
pseudostratified columnar epithelium
• Submucosa: connective tissue deep to the mucosa
• Adventitia: outermost layer, has C-shaped rings of
hyaline cartilage
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Trachea
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Trachea Histology
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Trachea Histology
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Seromucous Glands (Trachea)
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Trachea
Pseudostratified
Columnar
Epithelium
Submucosa with
seromucous
glands
Hyaline Cartilage
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Bronchi
Bronchioles
• Tissue walls of bronchi mimic that of the
trachea
• As conducting tubes become smaller,
structural changes occur and eventually they
become bronchioles
• Cartilage support structures change
• Bronchioles differ from bronchi in that they lack
cartilage
• Epithelium types change
• Amount of smooth muscle increases
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Bronchi Histology
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Bronchioles
Respiratory Bronchioles
• Respiratory Bronchioles : Continued
branching leads to the area where gas
exchange occurs by simple diffusion
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Bronchiole Histology
Notice the lack of cartilage
Simple columnar
epithelium
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Respiratory Bronchioles
Alveolar Ducts
Alveolar sacs
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Alveolar sacs
Alveoli
• Alveolar sacs look like clusters of grapes
• The “individual grapes” are Alveoli
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Alveoli Histology
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Type II Pneumocytes
are cuboidal and
produce surfactant
Type 1 Pneumocytes are
flattened for gas exchange
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Respiratory Membrane
•
The area where gas exchange between air and
blood occurs
• It is the fused alveolar and capillary walls (3
layers)
1. Squamous type 1 alveolar epithelium
2. Fused basal laminae
3. Squamous endothelial cells in pulmonary
capillaries
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Respiratory Membrane
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Lab Exercise 25
Respiratory System Physiology
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Terminology
 Pulmonary Ventilation: aka breathing, is the
movement of air into and out of the lungs
 External Respiration: The gas exchange between the
blood and alveoli (Partial pressure of oxygen in the
alveoli is greater than in the blood)
 Transport of gases: which is how oxygen and carbon
dioxide are carried by the blood between the lungs and
all tissues
 Internal Respiration: Exchange of gases between
systemic blood and tissue cells (pressures are opposite
from external respiration)
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Dalton’s law
• The total pressure of a
gas mixture is equal to
the partial pressures of
all the individual gases
in the compound
• During respiration,
oxygen and carbon
dioxide will move
along a pressure
gradient from high
conc. To low conc.
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Gas Exchange
• Almost all oxygen (98%) is transported by
binding to hemoglobin in RBCs.
• The remainder simply dissolves in the blood
plasma.
• Most carbon dioxide (68% to 78%) diffuses into
RBCs where it is converted to carbonic acid
(H2CO3)
• Carbonic acid quickly dissociates into
bicarbonate ions and hydrogen ions
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Acid Base Balance in Blood
• In the RBC and minimally in the plasma, this reaction
takes place
• CO2 + H2O  H2CO3  HCO3- + H+
• The bicarbonate ions (HCO3- ) help buffer the blood by
combining with extra H+ in the blood.
• Carbonic acid (H2CO3) releases H+ when the blood
becomes too basic.
• This way, the balance of H+ remains steady and the pH
is doesn’t fluctuate.
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Carbonic Acid Buffer System:
Dealing with Acids
• CO2 + H2O  H2CO3  HCO3- + H+
(Add an acid) + H+
• The H+ will combine with HCO3- to create
H2CO3
• H2CO3 will then dissociate into CO2 + H2O
• Breathing will increase to rid the body of the
extra CO2
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Carbonic Acid Buffer System:
Dealing with Bases
• CO2 + H2O  H2CO3  HCO3- + H+
(Add a base) + OH• The OH- will combine with H+ to create H2O
• H2CO3 will dissociate into HCO3- + H+ to
restore the H+ concentration
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Boyle’s Law
• The pressure of a gas
is inversely
proportional to its
volume.
• If the volume of the
thoracic cavity
increases, the air
pressure in the airways
decreases
This results in a pressure gradient that
forms between the atmosphere (high) and
the air ways (low) forces air to move into
the lungs
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Pulmonary Ventilation
• During inspiration, the
ribs are elevated and
the sternum moves
outward.
• During expiration, the
ribs are depressed and
the sternum moves
inward.
• The diaphragm is the
primary inspiratory
muscle
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Inspiration/Expiration
• Inspiration: Increase in thoracic cavity size
• Inspiratory muscles
• External intercostals (lift the rib cage)
• Diaphragm (Becomes flat)
• Expiration :Decrease in thoracic cavity size
• Expiratory muscles
• For the most part it is just the relaxation of the
inspiratory muscles (passive process)
• Internal intercostals & abdominal muscles used only
for forced expiration
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Muscles of Respiration
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Muscles: Inspiration
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Muscles: Expiration
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Spirometry
• Diagnostic technique
used to measure
respiratory volumes
• The instrument used is a
spirometer.
• It cannot measure the
amount of air in the lung,
only the amount entering
or leaving.
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Respiratory Volumes
• Tidal Volume TV
• Volume of air moved in or out of the lungs during
quiet breathing about 500 mL.
• Inspiratory Reserve Volume IRV
• Volume that can be inhaled during forced breathing in
addition to tidal volume 3100mL.
• Expiratory Reserve Volume ERV
• Volume that can be exhaled during forced breathing
after a normal tidal volume 1200 mL.
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Respiratory Volumes
• Residual Volume RV
* Can not be measured using spirometry*
• Volume that remains in the lungs at all times 1200
mL.
• The sum of two or more of these volumes is known
as a pulmonary capacity. The five pulmonary
capacities are as follows:
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Respiratory Capacity
• Vital Capacity VC
• Maximum volume that can be exhaled after taking
the deepest breath possible
VC = TV + IRV + ERV
• Inspiratory Capacity IC
• Maximum volume that can be inhaled after a normal
exhalation
IC = TV + IRV
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Respiratory Capacity
• Functional Residual Capacity FRC
• The amount of air left in the lungs after a
normal exhalation
FRC = ERV + RV
• Total Lung Capacity TLC
* can not be measured using spirometry*
• Total volume of air that the lungs can hold.
TLC = VC + RV
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Depth and Rate of Ventilation
• Eupnea- normal respiratory rhythm
• Hypoventilation- caused by breathing either
too shallowly or too slowly
• CO2 levels increase and pH lowers.
• Hyperventilation- a person over ventilates
eliminates carbon dioxide faster than it is
being produced causing the pH to increase.
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Activity 25.2
• Expiratory capacity is equal to the sum of the tidal
volume (TV) and expiratory reserve volume
(ERV)
• Is the maximum volume of air that can be
forcefully exhaled after a normal inhalation.
• Practice taking expiratory EC, ERV, TV and VC
• Do Activity 25.3: calculate volumes and capacities
follow instructions in manual
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The End
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