Chapter 15 – The Lung: Congenital Anomalies Flashcards

1
Q

The lungs are ingeniously constructed to carry out their cardinal function:

A

the exchange of
gases between inspired air and blood

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2
Q

Developmentally, the respiratory system is an outgrowth
from the ______________

A

ventral wall of the foregut.

The midline trachea develops two lateral outpocketings, the
lung buds.

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3
Q

Which lung deveop with 3 branches?

A

The right lung bud eventually divides into three branches—the lobar bronchi—and
the left into two lobar bronchi,

thRee= RIGHT

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4
Q

How many branches does the left lung has?

A

TWO

lefT

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5
Q

Why are aspirated foreign materials, such as vomitus, blood, and foreign bodies, tend to
enter the right lung
more than the left.

A

The right main stem bronchus is more vertical and more directly in line with the trachea.
Consequently, aspirated foreign materials, such as vomitus, blood, and foreign bodies, tend to
enter the right lung more than the left.

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6
Q

The lobar right and left bronchi branch _______,
giving rise to progressively smaller airways.

A

dichotomously

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7
Q

Describe the arterial supply of the lungs.

A

Accompanying the branching airways is the double
arterial supply to the lungs, that is, the pulmonary and bronchial arteries.

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8
Q

What is the order of branching towards the lungs?

A
  • bronchi
  • bronchioles
  • terminal bronchioles
  • acinus
    • respiratory bronchioles
    • alveolar ducts and
    • alveolar sacs
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9
Q

Differentiatebronchi forms bronchioles

A

which are distinguished from bronchi
by the lack of cartilage and submucosal glands within their walls.

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10
Q

Further branching of
bronchioles leads to the____________

A

terminal bronchioles, which are less than 2 mm in diameter

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11
Q

What is an acinus?

A

The part of
the lung distal to the terminal bronchiole
is called the acinus; it isroughly spherical, with a
diameter of about 7 mm.

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12
Q

An acinus is composed of :

A
  • respiratory bronchioles (which give off several alveoli from their sides),
  • alveolar ducts,
  • and alveolar sacs
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13
Q

What are alveolar sacs?

A

alveolar sacs, the blind ends of the
respiratory passages, whose walls are formed entirely of alveoli, which are the site of gas
exchange.

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14
Q

Whta is a pulmonary lobule?

A

A cluster of three to five terminal bronchioles, each with its appended acinus, is
referred to as the pulmonary lobule.

This lobular architecture assumes importance in
distinguishing the major forms of emphysema

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15
Q

What is the lining epithelium of the respiratory tree?

A

Except for the vocal cords, which are covered by stratified squamous epithelium, the entire
respiratory tree, including the larynx, trachea, and bronchioles, is lined by pseudostratified, tall,
columnar, ciliated epithelial cells.

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16
Q

What can you find the the bronchial mucosa?

A

The bronchial mucosa also contains a population of
neuroendocrine cells that have neurosecretory-type granules and can release a variety of
factors, including serotonin, calcitonin, and gastrin-releasing peptide (bombesin).

Numerous
mucus-secreting goblet cells and submucosal glands are dispersed throughout the walls of the
trachea and bronchi (but not the bronchioles).

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17
Q

Numerous
mucus-secreting goblet cells and submucosal glands are dispersed throughout the walls of the
trachea and bronchi and the bronchioles?

T or F

A

FALSE

Numerous
mucus-secreting goblet cells and submucosal glands are dispersed throughout the walls of the
trachea and bronchi (but not the bronchioles).

18
Q

The microscopic structure of the alveolar walls (or alveolar septa) consists, from blood to air, of
the following

A
  • Capillary endothelium
  • Basement membrane and surrounding interstitial tissue
  • Alveolar epithelium
  • Alveolar macrophages
19
Q

What separates the endothelial cells from the alveolar lining epithelial cells?

A

Basement membrane and surrounding interstitial tissue separating the endothelial cells
from the alveolar lining epithelial cells

20
Q

Describe thee difference between the thin portions of the alveolar septum from the thick portion of the alveolar septum.

A

. In thin portions of the alveolar septum, the
basement membranes of epithelium and endothelium are fused, whereas in thicker
portions they are separated by an interstitial space (pulmonary interstitium)
containing
fine elastic fibers, small bundles of collagen, a few fibroblast-like interstitial cells, smooth
muscle cells, mast cells, and rarely lymphocytes and monocytes.

21
Q

What are the contents of the pulmonary interstitium?

A

(pulmonary interstitium) containing

  • *fine elastic fibers, small bundles of collagen**, a few fibroblast-like interstitial cells, smooth
  • *muscle cells, mast cells, and rarely lymphocytes and monocytes.**
22
Q

Describe the alveolar epithelium.

A

Alveolar epithelium, a continuous layer of two cell types: flattened, platelike type I
pneumocytes covering 95% of the alveolar surface and rounded type II pneumocytes.

Type II cells synthesize surfactant, contained in osmiophilic lamellar bodies seen with
electron microscopy, and are involved in the repair of alveolar epithelium through their
ability to give rise to type I cells.

23
Q

What are the two types of cells of the alveolar epithelium?

A

Alveolar epithelium, a continuous layer of two cell types:

Type I and Type II

24
Q

What is the type I pneumocyte?

A

flattened, platelike type I
pneumocytes covering 95% of the alveolar surface

25
Q

Describe the type II pneumocytes.

A

rounded type II pneumocytes.

Type II cells synthesize surfactant, contained in osmiophilic lamellar bodies seen with
electron microscopy, and are involved in the repair of alveolar epithelium through their
ability to give rise to type I cells.

26
Q

Describe the alveolar macrpphages?

A

Alveolar macrophages, loosely attached to the epithelial cells or lying free within the
alveolar spaces, are derived from blood monocytes and belong to the mononuclear
phagocyte system.

Often, they are filled with carbon particles and other phagocytosed
materials.

27
Q

What are pores of Kohn?

A

The alveolar walls are perforated by numerous pores of Kohn, which permit the passage of
bacteria and exudate between adjacent alveoli (see Fig. 15-34B ).

Adjacent to the alveolar cell membrane is the pulmonary surfactant layer.

28
Q
A

FIGURE 15-1 Microscopic structure of the alveolar wall. Note that the basement membrane
(yellow) is thin on one side and widened where it is continuous with the interstitial space.
Portions of interstitial cells are shown.

29
Q
A

FIGURE 15-34 Stages of bacterial pneumonia.

A, Acute pneumonia. The congested septal
capillaries and extensive neutrophil exudation into alveoli corresponds to early red
hepatization. Fibrin nets have not yet formed.

B, Early organization of intra-alveolar exudate,
seen in areas to be streaming through the pores of Kohn (arrow).

C, Advanced organizing
pneumonia featuring transformation of exudates to fibromyxoid masses richly infiltrated by
macrophages and fibroblasts

30
Q

Whta are the stages of bacterial pneumonia?

A

A, Acute pneumonia. The congested septal
capillaries and extensive neutrophil exudation into alveoli corresponds to early red
hepatization. Fibrin nets have not yet formed.

B, Early organization of intra-alveolar exudate,
seen in areas to be streaming through the pores of Kohn (arrow).

C, Advanced organizing
pneumonia
featuring transformation of exudates to fibromyxoid masses richly infiltrated by
macrophages and fibroblasts

31
Q

Congenital Anomalies

Developmental defects of the lung include the following:

A
  • Agenesis or hypoplasia of both lungs, one lung, or single lobes
  • • Tracheal and bronchial anomalies (atresia, stenosis, tracheoesophageal fistula)
  • • Vascular anomalies
  • • Congenital lobar overinflation (emphysema)
  • • Foregut cysts
  • • Congenital pulmonary airway malformation
  • • Pulmonary sequestrations
32
Q

more common anomalies are

A
  • Pulmonary hypoplasia
  • Foregut cysts
  • Pulmonary sequestration
33
Q

What is pulmonary hypoplasia?

A

Pulmonary hypoplasia is the defective
development of both lungs
(one may be more affected than the other) resulting indecreased
weight, volume, and acini disproportional to the body weight and gestational age.

It is caused by
a variety of abnormalities that compress the lung(s) or impede normal lung expansion in utero
such as congenital diaphragmatic hernia and oligohydramnions.

34
Q

What is a foregut cyt?

A

Foregut cysts arise from an abnormal detachment of primitive foregut and are most often
located in the hilum or middle mediastinum.

Depending on the wall structure, these cysts are
classified as bronchogenic (most common)
,esophageal, or enteric.

A bronchogenic cyst is
rarely connected to the tracheobronchial tree. Microscopically, the cyst is lined by ciliated
pseudostratified columnar epithelium with squamous metaplasia occurring in areas of
inflammation
.

The wall contains bronchial glands, cartilage, and smooth muscle.

Surgical
resection is curative.

35
Q

What is pulmonary sequestration?

A

Pulmonary sequestration refers to the presence of a discrete mass of lung tissue *without
normal connection to the airway system.
*

36
Q

blood supply of the sequestered areas arises from the pulmonary arteries.

T or F

A

FALSE

Blood supply to the sequestered area arises not from
the pulmonary arteries
but from the aorta or its branches

37
Q

What are the two types of sequestration?

A
  • Extralobar sequestrations
  • Intralobar sequestrations
38
Q

What are extralobar sequestrations?

A

Extralobar sequestrations are
external to the lung and may be located anywhere in the thorax or mediastinum.

They most

  • *commonly come to attention in infants as abnormal mass lesions, and may be associated with**
  • *other congenital anomalies.**
39
Q

What are intralobar sequestrations?

A

Intralobar sequestrations occur within the lung substance usually in
older children and are often associated with recurrent localized infection or bronchiectasis.

40
Q
A