Pulmonary Anatomy and Physiology review Flashcards
The pulmonary airway structures that we need to know well include the following:
○ Trachea
○ Carina
○ Primary Bronchi
○ Secondary Bronchi
○ Tertiary Bronchi
○ Bronchioles
○ Alveoli
Trachea and Carina
○ Trachea- Flexible, semi-rigid tubular structure (“windpipe”).
○ Roughly 2.5 cm in diameter and 12-14 cm in length
● Extends through the mediastinum and
lies anterior to the esophagus.
● Carina- Internal ridge between bronchi
The Bronchi
The bronchial tree is a branched
system of air-conducting passages.
○ Originates at level of Carina
Aspirations often go this direction
Right Primary bronchus is more
vertically oriented
All types of bronchi exhibit some common characteristics:
○ Incomplete rings of cartilage continue
to keep the bronchi patent, although these rings become smaller and less numerous further into the tree.
○ All bronchi are lined with ciliated epithelium to help manage mucus.
○ A complete ring of smooth muscle develops between the epithelium and the cartilage rings
Eventually the bronchi branch
into tubules less than ___ mm in
diameter (no more cartilage).
1-2
Ciliated cells are replaced by
____ lining the bronchioles.
simple cuboidal or columnar
epithelium
Instead of cartilage keeping them patent, bronchioles have a _____
thicker layer of smooth muscle
The ____ is a thick layer of smooth muscle that helps regulate airway constriction or dilation.
muscularis
____ regulates the amount of air traveling
through the bronchial tree
Constriction or dilation of the bronchioles
What are the supporting
cells of the lungs that lay within the pulmonary interstitium?
Includes alveolar and capillary epithelium,
basement membrane, and perivascular/perilymphatic tissue
___ Pulmonary Arteries take oxygen-depleted blood from the right ventricle into the lungs
Two
Normal arterial pressure
within the pulmonary arteries is:
○ Systolic- 15-30 mmHg
○ Diastolic- 8-15 mmHg
Terminal bronchioles
branch into ____ , which
eventually terminate at
the ____
Respiratory bronchioles; Alveolar Pore
Each alveolus is encased in _____
pulmonary capillaries and supportive tissue
There are two types of cells in alveolar wall:
○ Alveolar Type 1- The predominant cell
type that promotes gas diffusion
○ Alveolar Type 2- Less common than
type 1, secretes Pulmonary Surfactant
Surfactant
fluid composed of lipids and proteins
that coats the inner surface of the alveoli.
● The purpose is to reduce surface tension and
prevent collapse of the alveoli during exhalation
In the womb, a fetus starts producing
surfactant in ___
the third trimester
____ is where CO2 is exchanged for O2 by the process of simple diffusion
The Alveolar-Capillary complex
Most O2 in the blood is bound to
hemoglobin in the form of
_____
Oxyhemoglobin
The large majority of CO2 in the
blood is transported in the form of
____
Bicarbonate (HCO3-)
____ has a higher PCO2 than
air in the Alveolus, so CO2 moves into
the Alveolus.
Venous blood
Partial pressure of ____ mmHg
correlates with O2 saturation of
approximately ____
60; 90%
A serous membrane called ____ lines the outer surfaces of the lungs and the adjacent internal thoracic wall.
Pleura
Pleura is formed from simple squamous
epithelium called ____
Mesothelium
____ tightly covers the entire outside of each lung
Visceral Pleura
_____ lines the internal thoracic walls,
superior surface of the diaphragm, and lateral parts of the mediastinum
Parietal Pleura
The ____ is a potential space between the
layers of pleura lubricated with serous fluid.
Pleural Cavity
Muscles involved in respiration:
○ Scalenes
○ Intercostals (Internal and External)
○ Diaphragm
The Scalenes
● Group of three muscles that extend from transverse process of cervical vertebrae to 1st and 2nd ribs
● The scalenes help increase vertical
dimensions of the thoracic cavity by
elevating the 1st and 2nd ribs
T/F the scalenes are used during baseline respiration
F
They are generally utilized during forced or aggressive inhalation.
External Intercostal fibers are
oriented ____ and contraction elevates the ribs.
“up and out,”
Internal Intercostal fibers are
oriented ____ and contraction depresses the ribs
“down and in,”
The ______ innervate ipsilateral domes of the Diaphragm, the main workhorse of respiration
Phrenic nerves (C3-4-5)
About ____ of air is inhaled
and exhaled with each breath
500 mL
Respiratory rate and depth are
controlled by _____
in the brainstem.
CNS Respiratory Centers
○ Specifically the Medulla
The strongest influencing factor of baseline respiratory rate is
arterial partial pressure of both O2
and CO2.
Two main CNS Respiratory Centers:
○ Dorsal Respiratory Group (DRG)
○ Ventral Respiratory Group (VRG)
Function of the DRG
● The DRG receives sensory input and
can influence respiratory muscles.
● The DRG is likely responsible for
baseline spontaneous respiration
Function of the VRG:
● The VRG can also influence the DRG
through interneurons (flows over if
drive increases for respirations).
_____ sensed by chemoreceptors in the aortic
and carotid bodies is the strongest modifier of CNS respiratory centers
Low arterial O2 or high
arterial CO2
____ (located in the medulla) influence the DRG and VRG, which results in increased respiratory rate.
Central Chemoreceptors
