MODULE 7 !
RESPIRATORY SYSTEM 1
I. ANATOMY
Divides into:!
- upper airways (nose to pharynx)(
- respiratory tract (larynx to lungs) !
# - further divided into a conducting zone (Þlteres, moistenened, warmed) and respiratory !
# zone (exchange of gases) !
A. Conducting Zone - warms (body temperature), Þlters (the mucus is sticky), and humidiÞes (mucus is
watery) the air due to the mucus-secreting cells (goblet cells) and the ciliated cells (moves the mucus
towards the oral cavity) = respiratory mucosa !
A. LARYNX - voice box; composed primarily of cartilage to hold the airway open. Contains: vocal cords
and epiglottis (a cartilage to close over the opening {glottis} to keep food and liquid from entering
lungs !
, B. TRACHEA - windpipe - held open by 15-20 c-shaped cartilages allows air to move through this
passageway, not a lot of smooth muscle here!
C. L & R MAIN (Primary) BRONCHI - these enter the lungs. Contain rings of cartilage to hold them open !
D. LOBAR (SECONDARY) BRONCHI - these contain plates of cartilage, smooth muscle in the walls!
E. SEGMENTAL (TERTIARY) BRONCHI - also have plates of cartilage, smooth muscle in the walls!
F. BRONCHIOLES - no cartilage, primarily smooth muscle in the wall. Maximum constriction and dilation
occurs here (regulates how much air test past this point) !
G. TERMINAL BRONCHIOLES - no cartilage, few goblet cells, does have cilia; end of conducting zone !
B. RESPIRATORY ZONE - by the time we get past the terminal bronchiole, the walls are so thin that gases
can diûuse across them. When the air leaves the terminal bronchiole, it passes into the respiratory
bronchiole -> alveolar ducts-> alveoli, organized into alveolar sacs!
# a) alveoli - very thin wall, permeable, gases can go in and out from here into the blood !
# b) capillaries all over the alveolar sacs and alveoli !
The alveolar walls are made up of TYPE I alveolar cells (Simple Squamous) sitting on a basement membrane
(some connective tissue) and the endothelial cells (simple squamous) of the lung capillaries. Allows for
diûusion of gases and collectively referred to as the RESPIRATORY MEMBRANE !
II. FORCES FOR PULMONARY VENTILATION - air into and out of the lungs. Remember - air always ßows
from an area of high pressure to an area of low pressure!
A. Pulmonary Pressures - 4 of them: !
A. Atmospheric Pressure - for simplicity we assume itÕs constant = 760 mmHg !
B. Intra-Alveolar/Intrapulmonary Pressure - at rest, it is equal to Atm. Pressure = 760 mmHg. Sometimes
it is listed as 0 mmHg (that is, relative to the atm. Pressure there is no pressure diûerence). It will drop
during inspiration, and rise during expiration. !
C. Intrapleural Pressure - it is the pressure in the ßuid-Þlled space (=pleural space) between the two
pleural tissues/membrane associated with the lung. At rest = 756 mmHg. Sometimes it is listed at -4
mmHg - relative to atm. pressure. !
RESPIRATORY SYSTEM 1
I. ANATOMY
Divides into:!
- upper airways (nose to pharynx)(
- respiratory tract (larynx to lungs) !
# - further divided into a conducting zone (Þlteres, moistenened, warmed) and respiratory !
# zone (exchange of gases) !
A. Conducting Zone - warms (body temperature), Þlters (the mucus is sticky), and humidiÞes (mucus is
watery) the air due to the mucus-secreting cells (goblet cells) and the ciliated cells (moves the mucus
towards the oral cavity) = respiratory mucosa !
A. LARYNX - voice box; composed primarily of cartilage to hold the airway open. Contains: vocal cords
and epiglottis (a cartilage to close over the opening {glottis} to keep food and liquid from entering
lungs !
, B. TRACHEA - windpipe - held open by 15-20 c-shaped cartilages allows air to move through this
passageway, not a lot of smooth muscle here!
C. L & R MAIN (Primary) BRONCHI - these enter the lungs. Contain rings of cartilage to hold them open !
D. LOBAR (SECONDARY) BRONCHI - these contain plates of cartilage, smooth muscle in the walls!
E. SEGMENTAL (TERTIARY) BRONCHI - also have plates of cartilage, smooth muscle in the walls!
F. BRONCHIOLES - no cartilage, primarily smooth muscle in the wall. Maximum constriction and dilation
occurs here (regulates how much air test past this point) !
G. TERMINAL BRONCHIOLES - no cartilage, few goblet cells, does have cilia; end of conducting zone !
B. RESPIRATORY ZONE - by the time we get past the terminal bronchiole, the walls are so thin that gases
can diûuse across them. When the air leaves the terminal bronchiole, it passes into the respiratory
bronchiole -> alveolar ducts-> alveoli, organized into alveolar sacs!
# a) alveoli - very thin wall, permeable, gases can go in and out from here into the blood !
# b) capillaries all over the alveolar sacs and alveoli !
The alveolar walls are made up of TYPE I alveolar cells (Simple Squamous) sitting on a basement membrane
(some connective tissue) and the endothelial cells (simple squamous) of the lung capillaries. Allows for
diûusion of gases and collectively referred to as the RESPIRATORY MEMBRANE !
II. FORCES FOR PULMONARY VENTILATION - air into and out of the lungs. Remember - air always ßows
from an area of high pressure to an area of low pressure!
A. Pulmonary Pressures - 4 of them: !
A. Atmospheric Pressure - for simplicity we assume itÕs constant = 760 mmHg !
B. Intra-Alveolar/Intrapulmonary Pressure - at rest, it is equal to Atm. Pressure = 760 mmHg. Sometimes
it is listed as 0 mmHg (that is, relative to the atm. Pressure there is no pressure diûerence). It will drop
during inspiration, and rise during expiration. !
C. Intrapleural Pressure - it is the pressure in the ßuid-Þlled space (=pleural space) between the two
pleural tissues/membrane associated with the lung. At rest = 756 mmHg. Sometimes it is listed at -4
mmHg - relative to atm. pressure. !
