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Respiratory System IPAP 11-1

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does gas diffusion occur in the conducting zone
no
nose -> terminal bronchioles
air gas vol. ~150 mL in 150lb adult
does gas diffusion occur in the respiratory zone
yes
respiratory bronchioles -> alveoli
air gas vol. ~ 5-6 L
what is the longest airway in the body
the trachea
what is the function of mucus in the respiratory tract
moisten inspired air
trap dust particles
how is inspired air warmed
blood circulating in the the mucosal capillary netwrok
the 3 regions of the pharynx
Naso-
oro-
laryngo-
what connects the laryngopharynx with the trachea
the larynx
"voice box"
where is the ciliated epithelium located in the larynx
below the vocal cords
where does cilia in the larynx move mucus to
upward towards the pharynx
this forms the anterior laryngeal wall and is the largest laryngeal cartilage
thyroid cartilage
this is in the "up" position during ventilation and in the "down" position during swallowing
epiglotis
this hyaline cartilage ring is at the inferior end of the larynx and is attached to the thyroid cartilage
circoid cartilage
Cricothyroidotomy (tracheotomy)
An emergency procedure used to establish an airway for patients with an upper airway obstruction
The thyroid cartilage is used as a landmark
An incision is made between the 1st and 2nd tracheal cartilages (through the cricothyroid ligament) or, less often, between the 2nd-4th tracheal cartilage
A small tube is inserted into the trachea and an O2 supply is attached
4 layers of tracheal wall (deep/luminal to superficial)
mucosa (ciliated epithelium & goblet cells)
submucosa (connective tissue)
Hyaline cartilage (16-20 rings - transverse smooth muscle fibers & elastic tissue)
Adventitia (anchors)
this is the most sensitive area for triggering the cough reflex
the carina
the carina is where the trachea
divides into R & L pulmonary bronchi
which bronchi is is more vertical, shorter, and wider
the right
the main bronchi cartilage is similar to
the incomplete cartilage rings of the trachea
due to its more vertical angle; fluid, food, or other foreign body aspiration is more likely to occur
in the right main stem primary bronchus
the secondary bronchi distribute where
to each lung lobe
R = 3
L = 2
what do the tertiary bronchi divide into
bronchioles
how many tertiary bronchi are there
10, one for each bronchopulmonary segment
the smallest airways of the conducting zone
terminal bronchioles
the largest airways of the respiratory zone
respiratory bronchioles
what happens as bronchioles get smaller
cartilage is gradually lost and replaced by spiral bands of smooth muscle
why do smooth muscle spasms interrupt air flow and adversley affect gas diffusion
there is no supporting cartolage in bronchioles
primary, secondary, and tertiary bronchi have
ciliated epithelium w/some goblet cells
how do the smaller bronchioles differ from the primary, secondary, and tertiary bronchi
their epithelium is ciliated, but there are no goblet cells
what is and isn't found in the terminal bronchioles
there are macrophages to remove inhaled particles and the epithelium is non-ciliated
what seperates the lungs
the mediastinum
if one lung collapses what will happen to the other
it will remain inflated
where is the cardiac notch
the depression on the medial surface of the left lung
what are the surfaces of the lungs
costal
mediastinal
diaphragmatic
what is the hilum
the area on the medial surface of the lung where bronchi, blood/lymph vessels, and nerves enter/exit the lungs
where is the diaphragm higher
on the right side
which lung is larger
the right 10%
it's thicker and broader, but shorter
what fills most of the space of the left hemithorax
the heart
what are the two porous serous membrane layers
parietal pleura- lines the wall of the pleural cavity
visceral pleura -covers each lung
what is the space between the parietal and visceral pleura
a potential space with a thin layer of viscous fluid
is air normally present in the pleural cavity
NO
• Pressure within the pleural cavity is normally
sub-atmospheric
pleural fluid allows
visceral and parietal pleurae to slide easily over each other during inhalation
is there a lot of pleural fluid
no, only a few mililiters (ml)
how is pleural fluid formed
from plasma filtrate and it's secreted from the pleura
what maintains the sub-atmospheric pressure within the pleural cavity
the Draining of pleural fluid from the pleural cavity via lymphatic capillaries and is returned to the blood circulation
what is the point of pleural surface tension
Pleural fluid causes the visceral and parietal pleura to "stick" together
Surface tension helps keep the lungs "up" (not collapsed)
what causes a pneumothorax
oSurface tension is broken and the lung (or lungs) collapse if air enters the pleural cavity (a pneumothorax)
persistent pleurisy/pleuritis often leads to
pleural effusion
pleurisy/pleuritis is
Inflammation of the pleural membrane having infectious and noninfectious etiologies
Often an extremely painful condition
pleural effusion is a
increase in pleural fluid secretion into the pleural cavity
May affect one or both lungs depending on the cause (etiology) and may adversely affect lung function
what divides the lungs into lobes
fissures
right lung oblique fissure extends inferiorly and anteriorly and
Superior part separates the superior and inferior lobes
Inferior part separates the inferior and middle lobes
left lung oblique fissure extends inferiorly and anteriorly and
separates the superior and inferior lobes
where is the horizontal fissure found
right lung only
Borders the middle lobe superiorly
what are the right lung lobes
superior, middle, and inferior
what are the left lung lobes
superior and inferior
what composes the anterior surface of each lung
the superior lobe
what does each lobe of the lung receive
a secondary (lobar) bronchus
Bronchopulmonary Segment is composed of
several small lobules
each lobule is wrapped in elastic connective tissue, what is contained within the lobules
Contains a pulmonary arteriole, a pulmonary venule, a lymph vessel, and a branch of the terminal bronchiole
where do terminal bronchioles subdivide into respiratory bronchioles
in the lobules
what lines the thin basement membrane of each cup shaped alveolus
simple squamous epithelium
the main site for gas diffusion is
Type I alveolar cells
an alveolar sac
is 2 + alveoli that share a common opening
the most numerous alveolar cells
`type 1
type I alveolar cells
The main sites for gas diffusion
Form part of the respiratory membrane (discussed later)
Most numerous
Composed of simple squamous epithelium
Form a nearly continuous lining of the alveolar wall
where are type II alveolar celss found
scattered amongst type I cells
what do type II alveolar celss do
secrete alveolar fluid
what does alveolar fluid do
moistens inspired air
where do you find alveolar fluid
on and between epithelial cells
what does alveolar fluid contain
surfactant
what is surfactant and what is its function
A mixture of lipoproteins and phospholipids that decreases the surface tension of alveolar fluid
Decreases incidence of alveolar collapse
dust cells
alveolar macrophages found in the alveolar walls that phagocytize that remove debris and fine dust particles from alveolar spaces
fibroblasts are found in the alveolar wall and they
produce elastic and reticular fibers that maintain the shape of the alveolar wall
the respiratory membrane is an enormaous surface area for gas diffusion
o There are approximately 300 million alveoli in both lungs = 750 square feet
what is the benefit of the respiratory membrane being only 0.5 micrometers thick
allows for RAPID gas diffusion
Respiratory Membrane Layers (listed in sequence from alveolar air space to the capillary umen/intravascular space)
Alveolar wall: type I and II alveolar cells and alveolar macrophages
Alveolar basement membrane surrounding the alveolar wall
Capillary basement membrane is often fused to the alveolar basement membrane
Capillary endothelium: a single layer of endothelial cells overlying the capillary basement membrane
what provides most blood flow to the lungs
pulmonary circulation
Pulmonary arteries and arterioles transport
venous (deoxygenated or mixed venous) blood from the right ventricle of the heart to the alveolar capillaries
CO2 diffusion from blood to alveoli and O2 diffusion from alveoli to the blood
external respiration
Pulmonary venules and veins transport
oxygenated blood to the left ventricle of the heart
Arterial (oxygenated) blood is pumped from the left ventricle into the systemic circulation
CO2 diffusion from tissue cells to tissue capillary blood and O2 diffusion from tissue capillary blood to tissue cells
Internal respiration
blood flow in bronchial circulation is
~70 ml/min/m2