NU 545
Unit 5 Study Guide
Advanced Pathophysiology
University of South Alabama.
This document provides a focused
study guide
It summarizes key concepts, lecture highlights, and
exam-relevant material to support efficient last-minute
review. The guide is structured to help students
reinforce understanding, identify weak areas, and prepare
confidently for the assessment.
, 1
UNIT 5: RESPIRATORY AND RENAL SYSTEMS
Physio-Pathological Basis of Advanced Nursing (NU 545)
Study Guide and Resources: Chapters 34 – 39
Edited by: Jessica L. Santos
1
, 2
SECTION 1: STUDY GUIDE
1. KNOW TYPE I AND TYPE II ALVEOLAR CELLS. (p. 1229; key search term: “lipoprotein
that coats”)
Bronchioles subdivide to form tiny tubes called alveolar ducts that end in
clusters of alveoli called alveolar sacs.
Alveoli are the primary gas-exchange units of the lung,
where O2 enters the blood and CO2 is removed.
Tiny passages called pores of Kohn permit some air to pass through the
septa from alveolus to alveolus, promoting collateral ventilation and even
distribution of air among the alveoli.
At birth, there are 50 million alveoli, by adulthood you have 480
million.
The alveolar septa (what separates each alveoli sac) has 2
layers (there is NO muscle layer)
─ Epithelial layer
─ Thin elastic basement membrane
Two major types of epithelial cells appear in the alveolus:
─ Type I alveolar cells: provide structure
─ Type II alveolar cells: (or “pneumonocytes”) secrete
surfactant (lipid protein that coats the inner surface of the
alveolus and facilitates its expansion during
inspiration, lowers alveolar surface
tension at end expiration, thus
preventing lung collapse)
Alveoli contain cellular components of
inflammation and immunity, particularly the mononuclear phagocytes.
─ Called alveolar macrophages
─ Ingest foreign material that reaches the alveolus and prepares it for removal
through lymphatics.
2
, 3
2. ROLE OF SURFACTANT IN THE LUNGS (INFANTS AND ADULTS). (pp. 1229, 1235,
1256, and 1292; key search term: “lipoprotein that coats” and “ventilation or
distention”)
Surfactant (p. 1229)
Secreted by Type II alveolar pneumonocyte cells.
Is a lipid protein that coats the inner surface of the alveolus and facilitates its expansion
during inspiration, lowers alveolar surface tension at end expiration, preventing lung
collapse.
Contributes to control of lung inflammation, and innate and adaptive immunity.
Surfactant (p. 1235)
Allows alveolar ventilation/distention to be possible- it lowers the surface tension by
coating the air liquid interface in the alveoli.
Surfactant is a lipoprotein (90% lipids, 10% protein)
There are 2 groups of surfactant proteins:
─ Group (SP-B and SP-C)
Consists of small hydrophobic molecules
Detergent like affect that separates liquid molecules = ↓surface tension
─ Group (SP-A and SP-D)
Consist of large hydrophobic molecules called collectins (pattern recognition
molecules)
Capable of inhibiting foreign pathogens
Surfactant lines the alveolar side of the alveolocapillary membrane and REVERSES
Laplace's law (where the pressure, P, required to inflate a sphere is = to 2x the surface
tension (ST) divided by the radius (R) of the sphere, or P= 2T/r)
As the radius of a surfactant lined sphere grows smaller (alveolus), the surface tension
DECREASES, and as the radius grows larger, the surface tension INCREASES.
This occurs because the surfactant
molecules have much weaker
intermolecular attraction compared
with the liquid molecules.
The surfactant molecules occupy most
of the air fluid interface and disrupt the
intramolecular forces that tend to
collapse the alveoli.
The alveoli are much easier to inflate at
low lung volumes (after expiration) than
at high volumes (after inspiration).
The decreased surface tension = alveoli
free of fluid.
Surfactant production disrupted or not
produced = ↑ surface tension =
alveolar collapse, ↓ lung expansion, ↑
work of breathing, and severe gas
exchange abnormalities.
Absence of surfactant = surface tension
tends to attract fluid into the alveoli.
Surfactant participates in host defense
against respiratory pathogens.
Surfactant Impairment (p. 1256)
Surfactant impairment results from decreased production or inactivation of surfactant,
which is necessary to reduce surface tension in the alveoli and thus prevent lung collapse
3
Unit 5 Study Guide
Advanced Pathophysiology
University of South Alabama.
This document provides a focused
study guide
It summarizes key concepts, lecture highlights, and
exam-relevant material to support efficient last-minute
review. The guide is structured to help students
reinforce understanding, identify weak areas, and prepare
confidently for the assessment.
, 1
UNIT 5: RESPIRATORY AND RENAL SYSTEMS
Physio-Pathological Basis of Advanced Nursing (NU 545)
Study Guide and Resources: Chapters 34 – 39
Edited by: Jessica L. Santos
1
, 2
SECTION 1: STUDY GUIDE
1. KNOW TYPE I AND TYPE II ALVEOLAR CELLS. (p. 1229; key search term: “lipoprotein
that coats”)
Bronchioles subdivide to form tiny tubes called alveolar ducts that end in
clusters of alveoli called alveolar sacs.
Alveoli are the primary gas-exchange units of the lung,
where O2 enters the blood and CO2 is removed.
Tiny passages called pores of Kohn permit some air to pass through the
septa from alveolus to alveolus, promoting collateral ventilation and even
distribution of air among the alveoli.
At birth, there are 50 million alveoli, by adulthood you have 480
million.
The alveolar septa (what separates each alveoli sac) has 2
layers (there is NO muscle layer)
─ Epithelial layer
─ Thin elastic basement membrane
Two major types of epithelial cells appear in the alveolus:
─ Type I alveolar cells: provide structure
─ Type II alveolar cells: (or “pneumonocytes”) secrete
surfactant (lipid protein that coats the inner surface of the
alveolus and facilitates its expansion during
inspiration, lowers alveolar surface
tension at end expiration, thus
preventing lung collapse)
Alveoli contain cellular components of
inflammation and immunity, particularly the mononuclear phagocytes.
─ Called alveolar macrophages
─ Ingest foreign material that reaches the alveolus and prepares it for removal
through lymphatics.
2
, 3
2. ROLE OF SURFACTANT IN THE LUNGS (INFANTS AND ADULTS). (pp. 1229, 1235,
1256, and 1292; key search term: “lipoprotein that coats” and “ventilation or
distention”)
Surfactant (p. 1229)
Secreted by Type II alveolar pneumonocyte cells.
Is a lipid protein that coats the inner surface of the alveolus and facilitates its expansion
during inspiration, lowers alveolar surface tension at end expiration, preventing lung
collapse.
Contributes to control of lung inflammation, and innate and adaptive immunity.
Surfactant (p. 1235)
Allows alveolar ventilation/distention to be possible- it lowers the surface tension by
coating the air liquid interface in the alveoli.
Surfactant is a lipoprotein (90% lipids, 10% protein)
There are 2 groups of surfactant proteins:
─ Group (SP-B and SP-C)
Consists of small hydrophobic molecules
Detergent like affect that separates liquid molecules = ↓surface tension
─ Group (SP-A and SP-D)
Consist of large hydrophobic molecules called collectins (pattern recognition
molecules)
Capable of inhibiting foreign pathogens
Surfactant lines the alveolar side of the alveolocapillary membrane and REVERSES
Laplace's law (where the pressure, P, required to inflate a sphere is = to 2x the surface
tension (ST) divided by the radius (R) of the sphere, or P= 2T/r)
As the radius of a surfactant lined sphere grows smaller (alveolus), the surface tension
DECREASES, and as the radius grows larger, the surface tension INCREASES.
This occurs because the surfactant
molecules have much weaker
intermolecular attraction compared
with the liquid molecules.
The surfactant molecules occupy most
of the air fluid interface and disrupt the
intramolecular forces that tend to
collapse the alveoli.
The alveoli are much easier to inflate at
low lung volumes (after expiration) than
at high volumes (after inspiration).
The decreased surface tension = alveoli
free of fluid.
Surfactant production disrupted or not
produced = ↑ surface tension =
alveolar collapse, ↓ lung expansion, ↑
work of breathing, and severe gas
exchange abnormalities.
Absence of surfactant = surface tension
tends to attract fluid into the alveoli.
Surfactant participates in host defense
against respiratory pathogens.
Surfactant Impairment (p. 1256)
Surfactant impairment results from decreased production or inactivation of surfactant,
which is necessary to reduce surface tension in the alveoli and thus prevent lung collapse
3
