Pulmonary Anatomy and Physiology review

Question 1

The pulmonary airway structures that we need to know well include the following:

Answer 1

○ Trachea
○ Carina
○ Primary Bronchi
○ Secondary Bronchi
○ Tertiary Bronchi
○ Bronchioles
○ Alveoli

Question 2

Trachea and Carina

Answer 2

○ 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

Question 3

The Bronchi

Answer 3

The bronchial tree is a branched
system of air-conducting passages.
○ Originates at level of Carina

Question 4

Aspirations often go this direction

Answer 4

Right Primary bronchus is more
vertically oriented

Question 5

All types of bronchi exhibit some common characteristics:

Answer 5

○ 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

Question 6

Eventually the bronchi branch
into tubules less than ___ mm in
diameter (no more cartilage).

Answer 6

1-2

Question 7

Ciliated cells are replaced by
____ lining the bronchioles.

Answer 7

simple cuboidal or columnar
epithelium

Question 8

Instead of cartilage keeping them patent, bronchioles have a _____

Answer 8

thicker layer of smooth muscle

Question 9

The ____ is a thick layer of smooth muscle that helps regulate airway constriction or dilation.

Answer 9

muscularis

Question 10

____ regulates the amount of air traveling
through the bronchial tree

Answer 10

Constriction or dilation of the bronchioles

Question 11

What are the supporting
cells of the lungs that lay within the pulmonary interstitium?

Answer 11

Includes alveolar and capillary epithelium,
basement membrane, and perivascular/perilymphatic tissue

Question 12

___ Pulmonary Arteries take oxygen-depleted blood from the right ventricle into the lungs

Answer 12

Two

Question 13

Normal arterial pressure
within the pulmonary arteries is:

Answer 13

○ Systolic- 15-30 mmHg
○ Diastolic- 8-15 mmHg

Question 14

Terminal bronchioles
branch into ____ , which
eventually terminate at
the ____

Answer 14

Respiratory bronchioles; Alveolar Pore

Question 15

Each alveolus is encased in _____

Answer 15

pulmonary capillaries and supportive tissue

Question 16

There are two types of cells in alveolar wall:

Answer 16

○ Alveolar Type 1- The predominant cell
type that promotes gas diffusion
○ Alveolar Type 2- Less common than
type 1, secretes Pulmonary Surfactant

Question 17

Surfactant

Answer 17

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

Question 18

In the womb, a fetus starts producing
surfactant in ___

Answer 18

the third trimester

Question 19

____ is where CO2 is exchanged for O2 by the process of simple diffusion

Answer 19

The Alveolar-Capillary complex

Question 20

Most O2 in the blood is bound to
hemoglobin in the form of
_____

Answer 20

Oxyhemoglobin

Question 21

The large majority of CO2 in the
blood is transported in the form of
____

Answer 21

Bicarbonate (HCO3-)

Question 22

____ has a higher PCO2 than
air in the Alveolus, so CO2 moves into
the Alveolus.

Answer 22

Venous blood

Question 23

Partial pressure of ____ mmHg
correlates with O2 saturation of
approximately ____

Answer 23

60; 90%

Question 24

A serous membrane called ____ lines the outer surfaces of the lungs and the adjacent internal thoracic wall.

Answer 24

Pleura

Question 25

Pleura is formed from simple squamous
epithelium called ____

Answer 25

Mesothelium

Question 26

____ tightly covers the entire outside of each lung

Answer 26

Visceral Pleura

Question 27

_____ lines the internal thoracic walls,
superior surface of the diaphragm, and lateral parts of the mediastinum

Answer 27

Parietal Pleura

Question 28

The ____ is a potential space between the
layers of pleura lubricated with serous fluid.

Answer 28

Pleural Cavity

Question 29

Muscles involved in respiration:

Answer 29

○ Scalenes
○ Intercostals (Internal and External)
○ Diaphragm

Question 30

The Scalenes

Answer 30

● 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

Question 31

T/F the scalenes are used during baseline respiration

Answer 31

F
They are generally utilized during forced or aggressive inhalation.

Question 32

External Intercostal fibers are
oriented ____ and contraction elevates the ribs.

Answer 32

“up and out,”

Question 33

Internal Intercostal fibers are
oriented ____ and contraction depresses the ribs

Answer 33

“down and in,”

Question 34

The ______ innervate ipsilateral domes of the Diaphragm, the main workhorse of respiration

Answer 34

Phrenic nerves (C3-4-5)

Question 35

About ____ of air is inhaled
and exhaled with each breath

Answer 35

500 mL

Question 36

Respiratory rate and depth are
controlled by _____
in the brainstem.

Answer 36

CNS Respiratory Centers
○ Specifically the Medulla

Question 37

The strongest influencing factor of baseline respiratory rate is

Answer 37

arterial partial pressure of both O2
and CO2.

Question 38

Two main CNS Respiratory Centers:

Answer 38

○ Dorsal Respiratory Group (DRG)
○ Ventral Respiratory Group (VRG)

Question 39

Function of the DRG

Answer 39

● The DRG receives sensory input and
can influence respiratory muscles.
● The DRG is likely responsible for
baseline spontaneous respiration

Question 40

Function of the VRG:

Answer 40

● The VRG can also influence the DRG
through interneurons (flows over if
drive increases for respirations).

Question 41

_____ sensed by chemoreceptors in the aortic
and carotid bodies is the strongest modifier of CNS respiratory centers

Answer 41

Low arterial O2 or high
arterial CO2

Question 42

____ (located in the medulla) influence the DRG and VRG, which results in increased respiratory rate.

Answer 42

Central Chemoreceptors