Anatomy & Physiology 34B
Chapter 22 - Respiratory System
I.
Overview
A. Introduction
B. Conducting Passages
C. Pulmonary Alveoli, Lungs, & Pleurae
D. Mechanics of Ventilation
E. Neural Control of Ventilation
F. Gas Exchange & Transport
G. Blood Chemistry and Respiratory Rhythm
H. Respiratory Disorders
II. Introduction to the _______________ System
A. The major role of this system is to supply body tissues with ___________ and dispose of
____________________ (gas exchange)
B. _______________ refers to 4 main functions:
1. Pulmonary _______________ - breathing
2. ___________ respiration - gas exchanges between the air & blood at the lung alveoli
3. _______________ of respiratory gases via the circulatory system
4. _____________ respiration – gas exchange between tissues & capillaries
C. The respiratory system can be divided _____________ into upper & lower divisions, and
__________________ into a conducting & a respiratory division
D. Basic _______________ of the Respiratory System
1. Major passages & structures of the respiratory system are the
a. ___________ respiratory - nasal cavity, pharynx, larynx, and trachea superior to
the lungs
b.
__________ respiratory - bronchi, bronchioles, and pulmonary alveoli within the
lungs
2. Air passes from nasal cavity  pharynx  larynx  ____________  bronchi 
bronchioles  _____________
3. The _______________ division includes all the cavities and structures that transport
gases to & from the pulmonary alveoli
4. The ___________ division consists of the pulmonary ______, which are the functional
units of the respiratory system, where gas exchange between the air and blood occur
III. _____________ Passages - transport air to the lungs; passages are lined with __________
that cleanse, warm, and humidify the air
A. Nose - includes an external portion, the external _______, that opens to an internal nasal
cavity, the nasal ___________
1.
The nasal _________ is formed by the following skull bones
2
a.
b.
Roof - frontal & _______ bones
c.
d.
Posteriorly - __________ bone
e.
Medially – the nasal ________ formed by the perpendicular plate of the ethmoid,
vomer, & septal cartilage
Floor – ______ palate, formed by the palatine & maxillary bones, and muscular
______ palate
Lateral walls have 3 bony projections: the superior, middle, and inferior nasal
__________ (turbinates)
2.
The conchae are lined with _________________ ciliated columnar epithelium that
contain mucus-secreting __________ cells
3.
4.
Nasal hairs (___________) in the nostrils filter inhaled macroparticles
The main function of the nasal cavity is to _____, moisten, and filter the inspired air
a. Debris from air is trapped in the _______
b. _________ move the mucus to the pharynx, where it is swallowed
5. ____________ is an inflammation of the nasal mucosa.
B. ____________ Sinuses - communicate with the nasal cavity via drainage ducts.
These
paired sinuses include the FEMS:
1.
2.
3.
4.
5.
____________
____________
_____________
_____________
_______________ is an inflammation of these sinuses.
C. ______________ (throat) is divided into 3 regions:
1. ______pharynx - uppermost pharynx, behind the nasal cavity and above the soft
palate; contains the
2.
3.
a.
_________ - hangs from the middle part of the soft palate; both block the nasal
cavity during swallowing
b.
c.
_____________ tubes - connect the nasopharynx with the middle ear cavities
Pharyngeal tonsils (________) are found in the posterior wall of the nasal cavity
____pharynx - mid-pharynx between the soft palate and hyoid bone; contains paired
a.
____________ tonsils on the posterior lateral wall; often become infected and are
removed during a tonsilectomy
b.
Lingual tonsils on the base of the _________
_____________pharynx - posterior pharynx extends downward from the hyoid bone
and opens into the esophagus & larynx.
a. Food goes into the _______________
b. Air moves through the ___________ into the larynx and trachea
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D. ____________ (“voice box”) - in anterior midline of the neck at C4-C6
1. The larynx prevents food from entering the ___________ and produces sound
2. It is composed of 9 ____________: 3 large unpaired and 6 smaller paired structures
a. _________ cartilage - large, unpaired, anterior structure with a laryngeal
prominence (________ apple)
3.
b.
_______________ - composed of elastic cartilage, located behind the root of the
tongue; during swallowing, it folds over the _________ opening to the larynx
c.
___________ cartilage - ring shaped base of larynx; connects thyroid cartilage to
the trachea
d.
_________ cartilages - paired above the cricoid and behind the thyroid; posterior
attachments of the vocal folds
e.
_____________ & corniculate cartilages - paired, small accessory structures
associated with the arytenoid cartilages
Two pairs of strong CT bands are stretched between the thyroid & __________
cartilages
a.
b.
4.
________ folds (true vocal cords) - vibrate to produce sound
___________ folds (false vocal cords) - support the vocal folds, but do not
produce sound
Laryngeal _____________ include
a.
b.
______________ muscles - elevate the larynx during swallowing
____________ muscles - change length, position, & tension of the vocal folds
5. _____________ is an inflammation of the larynx
E. ______________ (windpipe)
1. Rigid tube anterior to the __________; connects the larynx to the primary bronchi
2. 16-20 anterior hyaline cartilage _________ form the supporting walls of the trachea
3. The trachea mucosal lining consists of ____________________ ciliated columnar
epithelium with many goblet cells; this moves particles out of the lungs
4.
Medial to the lungs, the trachea splits at the ______ to form the left and right primary
bronchi
F. _________ ________ - respiratory tubes branch into progressively narrower tubes as they
extend into the lungs in the following order:
1.
2.
3.
4.
5.
6.
7.
L. & R. ____________ bronchi
____________ (lobular) bronchi
____________ (segmental) bronchi
______________
______________ bronchioles
______________ bronchioles
Alveolar _______
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8.
9.
Alveolar _____
Pulmonary ____________
G. The ___________ portion ends at the terminal bronchioles and the ___________ portion
begins at the respiratory bronchioles
IV. Pulmonary Alveoli, Lungs, & Pluera
A. Pulmonary Alveoli
1. Alveolar sacs are clusters of tiny pulmonary __________, the functional units of the
respiratory system. Alveolar _____ are
a. Type I – simple ___________ epithelium surrounded by a basal lamina, forming a
thin ______________________ shared by alveoli and surrounding capillaries
b. Type II – ___________ epithelium that secretes lubricating ______________ that
keeps alveoli from sticking together
c. Alveolar _______________ that phagocytize pathogens
2.
Gas exchange occurs across the respiratory _____________ between the alveoli and
their associated capillaries
a.
b.
___________ diffuses across the alveoli walls into the capillaries
__________ diffuses from the capillaries into the alveoli
B. ______ - paired respiratory organs lateral to the mediastinum and surrounded by the rib
cage within the thoracic cavity
1.
2.
Each lung has 4 surfaces:
a.
______________ (medial) surface - slightly concave and contains a verticle slit,
the hilum through which pulmonary vessels, nerves, & bronchi pass
b.
c.
d.
______ - concave inferior surface that fits over the diaphragm
______ - pointed, superior surface that extends above the clavicle
___________ surface - rounded lateral surface in contact with the membranes
covering the lungs
Right & left lungs are similar, but have some differences:
a.
Left lung has a ________ notch on its medial surface and is divided by a ______
fissure into a superior and inferior lobe
b.
c.
Right lung is divided by ____ fissures into superior, middle, and inferior lobes.
Each lobe is further divided into many smaller ___________, which contain the
pulmonary alveoli
C. _________ - serous membranes that surround the lungs and line the thoracic cavity
include the
1.
___________ pleura adheres to the outer lung surface and extends into the
interlobular fissures
2.
___________ pleura lines the thoracic cavity and the mediastinum, thus both lungs
are in separate compartments
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3.
A pleural _______ is a potential space between the visceral & parietal pleura; pleural
fluid in this cavity allows the membranes to slide smoothly across each other during
respiration
4.
____________ is an inflammation of the pleura, which causes friction between lungs
and thoracic cavity, making breathing difficult
V. Mechanics of Ventilation
A. Pulmonary _____________ (breathing) consists of two phases: inspiration (inhaling)
and expiration (exhaling)
B. Relaxed ___________ involves contractions of the diaphragm and external intercostal
muscles
1.
Contraction of the dome-shaped _______ causes it to flatten, increasing lung volume;
contractions of the external intercostals lift the ribs, further increasing lung volume
a. _________ Law – the pressure of a quantity of gas is inversely proportional to the
volume of its container (P1/V)
b. During inspiration alveolar volume increases, which __________ intrapulmonary
pressure below atmospheric pressure (760 mm Hg  757 mm Hg)
c. In terms of ________ pressure, if atmospheric pressure was 0, the intrapulmonary
pressure would be –3 mm Hg; thus air flows _____ the lungs
d. Intrapleural pressure (-4  -6 mm Hg) is the pressure in the __________ cavity,
which is always more negative than the intrapulmonary pressure, and acts as a
suction to keep lungs inflated
e. Transpulmonary pressure is the difference between the intrapulmonary and
_____________ pressures (757  754 mm Hg); this helps the lungs to expand in
the thoracic cavity
2.
Nerves involved include the __________, intercostal, accessory, cervical, & thoracic
nerves
C. Forced inspiration involves contractions of the ___________ and sternocleidomastoid
muscles, which further elevate the ribs
D. Relaxed __________ - muscles of inspiration relax, ribs return to their original position,
elastic tissue in the lungs and bronchial tree allow them to recoil
1. Lung internal volume decreases, causing intrapulmonary pressure to ____________
2. Intrapulmonary pressure becomes +3 mm Hg above atmospheric pressure, so air flows
_____ of the lungs
E. During forced expiration, internal intercostals and _____________ muscles contract in
response to intercostal and lower spinal nerves
F. Other factors affecting respiration include resistance to airflow, alvoelar surface tension,
and alveolar ventilation
1. _____________ to airflow within airways is affected by pulmonary compliance and
bronchiole diameter (F  Pressure/Resistance)
a. Pulmonary __________, the ease with which the lungs expand, can be reduced by
lung diseases that increase resistance, thus decreasing air flow
b. Changes in bronchiole ____________ affect resistance
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1) Bronchoconstriction occurs when parasympathetic nerves or histamine _______
bronchioles, leading to increased resistance and ______________ air flow
2) Bronchodilation occurs when epinephrine, released by the adrenal gland during
exercise or stress, _________ bronchioles, leading to decreased resistance and
____________ air flow
2. Alveolar ____________________ is reduced by surfactant
a. Surfactant is a lipoprotein produced by type ___ alveolar cells; it reduces alveolar
surface tension, allowing the alveoli to recoil during expiration
b. Premature infants are often deficient in surfactant, which causes hyaline
membrane disease (Respiratory ____________ Syndrome)
3. Alveolar ventilation is limited by the amount of air that reaches functional ________
a. The conducting division of the respiratory system is called anatomical _________
because air here is not involved in gas exchange
b. _______________ dead space is the sum of the anatomical dead space and
pathological alveolar dead space
c. Alveolar ________________ is determined by taking the difference of the inhaled
air (500 ml) minus the dead air (150 ml), then multiplying the result by the
respiratory rate (BPM)
G. Measurements of Ventilation can be obtained via a ______________, which captures
expired air and records the rate and depth of breathing, speed of expiration, and rate of
oxygen consumption. Measurements are respiratory volumes or respiratory capacities
1. ________ volume (TV) - amount of air inhaled or exhaled in one respiratory cycle
(500 mL)
2. _____________reserve volume (IRV) – amount of air above the tidal volume that
can be inhaled with maximum effort (3,000 mL)
3. ______________reserve volume (ERV) – amount of air above the tidal volume that
can be exhaled with maximum effort (1,200 mL)
4. ____________ volume (RV) – amount of air left in lungs after maximum expiration
(1,300 mL)
5. _________________ – amount of air that can be exhaled with maximum effort after
maximum inspiration (VC = TV + IRV + ERV) (4,700 mL)
6. _________ expiratory volume (FEV) – percent of the vital capacity that can be
exhaled in a given time interval.
1) Healthy adults should be able to expel 75-85% of the vital ___________ in one
second.
2) Inability to do so may indicate respiratory ____________
VI. Neural Control of Ventilation
A. The three ___________ _____________ of the brain are the
1. ______________ area in the medulla oblongata contains nerve cell bodies that form
the inspiratory and expiratory portions
a. Inspiratory (I) neurons fire during _____________
b. Expiratory (E) neurons fire during forced ____________
2.
Apneustic & pneumotaxic areas in the _____ influence the activity of the
rhythmicity area
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a.
b.
______________ center prolongs inspiration
___________________ center inhibits medullary inspiratory neurons
B. Excessive inflation in the lungs triggers the Hering-Breuer _______, in which inspiratory
neurons are inhibited and expiration results
C. Breathing can be voluntarily controlled to a point. Holding one’s breath lowers the ___
level and raises the ____ level in the blood until autonomic controls force the person to
breath
VII. Gas Exchange & Transport
A. Air is a mixture of ______: 78.6% N2, 20.9% O2, 0.46% H20, and 0.04% CO2 (note that
alveolar air differs in percentages)
1. Each gas contributes a ________ ___________ to the total atmospheric pressure in
proportion to its percentage (e.g., Patm = PN2 + PO2 + PH2O + PCO2 = 597 + 159 +
3.7 + 0.3 = 760 mm Hg)
2. ____________ Law – the total pressure of a gas mixture is the sum of the partial
pressures of the individual gases
3. Partial gas pressures are important because they determine the rate of _____________
of a gas, and thus affect the rate of gas exchange between the blood and alveolar air
B. At the Air-Water Interface (as in the pulmonary alveolus), gases diffuse down their
concentration gradients until __________________ is reached
1. ____________ Law – the amount of gas that dissolves in a liquid is proportional to
a. the partial ____________ of the gas and
b. the _____________ of the gas
C. Gas ___________ – the process of carrying gases from the alveoli to the systemic tissues
and back
1. ________ transport is accomplished mainly by O2 binding to ___ (98.5%), with a
slight percentage dissolved in the plasma (1.5%)
a. At high PO2 (as in the lungs), Hb has a ___ _______ for O2; the iron in each of the
4 heme groups binds one O2 molecule, and Hb becomes oxyhemoglobin (_____)
b. At low PO2 (as in the tissues), Hb has a ______________ for O2, so the heme
groups release the O2 to diffuse out to the tissues. Once the O2 is released, the Hb
becomes _______hemoglobin
c. Hb has a higher affinity for ____ than it does for O2, so if CO is present, it will
competitively bind to Hb, preventing ____ from binding, which can lead to death
2. Carbon _______ transport is accomplished in three ways: as carbonic acid, carbamino
compounds, and dissolved gas
a. About 70% of CO2 reacts with water to form carbonic acid (________), which then
dissociates into bicarbonate (______) and hydrogen ions (__) in RBCs. This rxn. is
facilitated by the enzyme carbonic anhydrase (____)
CO2 + H2O  H2CO3  HCO3- + H+
CAH
b. About 23% of CO2 binds with hemoglobin to form carbaminohemoglobin (______).
CO2 does not compete with O2 because they bind to different sites on Hb.
c. The remaining 7% of CO2 is carried in blood ________ as a dissolved gas, like the
CO2 in soda pop (note: CAH is present in RBCs, but not in plasma)
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D. ____________ Gas Exchange is the unloading of O2 and loading of CO2 at the systemic
capillaries in tissues
1. CO2 loading – CO2 is a by product of cellular __________ in tissues, therefore PCO2
is higher in tissues than in capillaries, thus CO2 diffuses ____ the bloodstream
2. Oxygen unloading- __________ ions dissociated from carbonic acid bind to
____hemoglobin, which reduces Hb’s affinity for O2, causing the release of O2, which
diffuses to surrounding tissues
E. ___________ gas exchange is the loading of O2 and unloading of CO2 at the alveolar
capillaries
1. More PO2 in alveolar air than in capillary blood allows O2 to diffuse into the _______
(O2 loading)
a. As Hb loads O2, its affinity for ____ declines
b. Hydrogen ions dissociate from Hb and bind with ___________ ions transported
from the plasma into RBCs
c. The reaction of H+ and HCO3- reverses the previous hydration rxn. and generates
free _____
2. Greater PCO2 in the capillary blood than in the alveolus allows CO2 to diffuse into the
____________ (CO2 unloading)
3. Even though PO2 is  CO2, equal amounts of O2 and CO2 are exchanged across the
respiratory membrane because CO2 is much more ___________ than O2
F. Adjustment to Changing Metabolic Needs of Tissues
1. Four factors adjust the rate of ____ unloading
a. Ambient O2 - Active tissues consume O2 rapidly, leading to a ________ PO2 than
resting tissues, thus HbO2 releases more O2 to active tissues
b. ___________ – elevated temperature in active tissues also promotes O2 unloading
c. Bohr effect – active tissues generate extra CO2, which raises the ___ concentration
and lowers blood ___; this also promotes O2 unloading
d. Bisphosphoglycerate (___), an enzyme in anerobic respiration in RBCs, binds to
Hb and promotes O2 unloading
2. CO2 loading is affected by a low level of _____, which enables Hb to transport more
CO2 (the Haldane effect)
VIII. Blood Chemistry & Respiratory Rhythm
A. Two groups of ___________________ respond to changes in blood chemistry
1.
___________ chemoreceptors in the MO monitor the ___ of the CSF and tissue fluid
of the brain
2.
_______________ chemoreceptors in the aortic and carotid bodies
a.
b.
Aortic bodies in the _______ arch send sensory information to the MO in the
__________ nerves
Carotid bodies in the ___________ arteries stimulate sensory fibers in the
glossopharyngeal nerve
B. Effects of hydrogen ions, O2 and CO2 concentrations on respiration
1. Hydrogen ion concentration (___) in the brain is controlled mainly by ventilation
a. Blood pH is determined largely by _____ because of the rxn. CO2 + H2O 
H2CO3  HCO3- + H+
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b. The more CO2 is present, the more H+ is generated, the lower the pH; less CO2 =
_____ H+ ions = _________ pH
c. Blood pH must be maintained within a narrow range of 7.35-7.45; lower is called
___________, higher is ___________
d. Respiratory acidosis is usually caused by excess CO2 (____________), which can
be corrected by _____________ ventilation to expel more CO2
e. Respiratory alkalosis is usually caused by low CO2 (_____________), which can
be corrected by ____________ ventilation to allow CO2 to build up in the blood
2. Carbon dioxide – at the beginning of exercise, rising ___ levels stimulate peripheral
chemoreceptors, which trigger an ______________ in ventilation
3. Oxygen – PO2 usually has little effect on ventilation, but long term _____________
(as in emphysema and mountain climbing) can trigger ____________ drive, in which
ventilation is increased
IX. Respiratory Disorders
A. ____________, a deficiency of O2 in the tissues, can cause cyanosis and, if severe and
prolonged, can lead to tissue necrosis
B. Trauma or Injury Problems
1. _____________ is a condition in which the lung(s) collapse (atelectasis) if air enters
the pleural cavity.
2. ___________ - foreign object lodges in the trachea; may be dislodged by the
____________ maneuver
C. Chronic obstructive pulmonary diseases (_________s)
1. _____________ - acute infection & inflammation of the lung accompanied by fluid
buildup; may be caused by bacteria, virus, or fungus
2.
________________ - inflammatory lung disease contracted by inhaling tuberculosis
bacteria from a carrier
3.
____________ - caused by allergy to inhaled antigens; causes a swelling or blockage
of lower respiratory tubes
4.
Chronic ___________ – often found in smokers, tobacco smoke paralyzes and
eventually destroys cilia and alveolar macrophages; excess mucus production leads to
coughing and infection
5.
________________ - causes the breakdown of the pulmonary alveoli, increasing the
size of air spaces and decreasing their surface area and respiration; frequent cause of
death among smokers.
D. __________________, which causes 1/3 of all cancer deaths in the U.S., is caused mostly
by tobacco smoke, which contains numerous carcinogenic compounds
1. Three forms of lung cancer are ________ cell carcinoma, _____carcinoma, and
________________ carcinoma
2. Symptoms include chronic coughing and ________ in the sputum
3. Lung cancer ______________ so rapidly, it has usually spread to other organs by the
time it is diagnosed, and prognosis is poor