respiratory system path Flashcards
refers to an area or areas of airless pulmonary parenchyma, due to collapse or incomplete expansion
atelectasis
◦ Complete obstruction of an airway
◦ Air within the dependent lung is resorbed→ collapse
◦ Mediastinum shifts toward the affected lung
resorption atelectasis
in resorption atelectasis, mediastinum shifts ____the affected lung
toward
◦ Fluid, tumor or air accumulate within the
pleural space, preventing normal
expansion
◦ Mediastinum shifts away from the
affected lung
compression atelectasis
in compression atelectasis, mediastinum shifts ____from affected lung
away
◦ Pulmonary or pleural fibrosis preventing
normal expansion
◦Not reversible
contraction atelectasis
two types of pulmonary edema
- hemodynamic pulmonary edema
- edema secondary to microvascular (alveolar injury)
◦ Intra-alveolar fluid accumulation due to increased hydrostatic pressure
in the pulmonary circulation (fluid forced out of them)
◦ Hemosiderin-laden macrophages may be seen within alveoli (“heart
failure cells”) with chronic pulmonary edema
◦ ↓oxygenation, ↑ chance of infection
Hemodynamic pulmonary edema
(heart failure)
◦ Injury to and inflammation of alveolar vascular endothelium and/or
respiratory epithelium
◦ Infectious or toxic insults
◦ May be localized or diffuse
Edema secondary to microvascular (alveolar) injury
Characterized by an increase in resistance to airflow due to
partial or complete obstruction at any level from the
trachea and larger bronchi to the terminal and respiratory
bronchioles
obstructive lung diseases
demonstrated with pulmonary function testing,
which will show decreased maximal flow rates during forced
expiration
obstructive lung diseases
obstructive lung diseases:
1
2
3
4
- emphysema
- chronic bronchitits
- asthma
- bronchiectasis
(COPD are 1 and 2 together)
in COPD, who are most susceptible to COPD than other groups
women and african americans
COPD has a strong association with:
smoking
35-50% of heavy smokers develop COPD
80% of COPD is due to smokinh
other risks: environment/occupational pollution
Destruction of airway walls and irreversible enlargement of
the airways distal to the terminal bronchiole
emphysema
emphysema is classified based upon the site of involvement within a pulmonary acinus:
- centriacinar
- panacinar
- distal acinar
- irregular
- Occurs predominantly in heavy smokers, often along with chronic bronchitis (COPD)
- respiratory bronchioles are involved, sparing the distal alveoli
- more lesions seen in upper lobes/apical segments
centriacinar emphysema
- Associated with α1
-antitrypsin deficiency - Alveoli distal to the respiratory bronchioles are involved
- occurs more frequently in the lower and anterior aspects of
the lungs (lung bases are most severely involved)
panacinar emphysema
emphysema pathogenesis
- Exposure to injurious particles in tobacco smoke stimulates
inflammation - imbalance of proteases and antiproteases
- oxidative stress
emphysema pathogenesis
what is
Lung epithelial cells and macrophages release chemotactic factors
(IL-8, TNF, etc) to recruit inflammatory cells from the circulation
Exposure to injurious particles in tobacco smoke stimulates
inflammation
emphysema pathogenesis
what is
Inflammatory cells release destructive proteases (elastase)
imbalance of proteases and antiproteases
emphysema pathogenesis
what is
Smoke, inflammatory cell products contain oxidants, continuing
the cycle of tissue damage and inflammation
oxidative stress
potent antiprotease, encoded by the Pi
locus on chromosome 14
a1 antitrypsin deficiency
Homozygotes for the ___ allele (0.012% of population) have significant decrease in a1 antitrypsin
Z allele
of homozygotes (PiZZ) will develop symptomatic
panacinar emphysema, accelerated and more severe if the
patient smokes
80%
How is emphysema an obstructive lung
disease?
-small airways are normally held open by the elastic recoil of lung parenchyma
-destruction of elastic alveolar walls surrounding respiratory bronchioles leads to the collapse of those bronchioles during expiration
[can breathe air in, but not out]
emphysema doesnt show symptoms until
1/3 of lung tissue affected
emphysema symptoms
dyspnea
cough
wheezing
with severe:
◦ weight loss
◦ Barrel chest -overdistension
◦ Prolonged expiration
Emphysema may progress to pulmonary ____ and_____
pulmonary hypertension and right-sided heart failure (RHF)
death in emphysma
respiratory failure
RHF
pneumothorax-> lung collapse
chronic, persistent productive cough without any other
identifiable cause
common in smokers
chronic bronchitis
pathogenesis of this includes:
- initiating factor is exposure of bronchi to inhaled irritants
- mucus hypersecretion
- chronic inflammation -> damage and fibrosis of small airways
- diminished ciliary action of respiratory epithelium, leading to stasis of mucus
chronic bronchitis pathogenesis
- Edema and swelling of the respiratory mucosa, often with
squamous metaplasia - hyperplasia of submucosal glands of the trachea and larger bronchi (thickness of mucus gland layer increases)
- increased globlet cells in small bronchi and bronchioles and extensive small airway mucous pluging
chronic bronchitis morphologic changes
chronic bronchitis clinical:
persistent productive cough
dyspnea on exertion
classically:
-hypercapnia
-hypoxia
-mild cyanosis
Chronic disorder of the conducting airways, characterized by:
◦ Recurrent bronchoconstriction, associated with a variety of stimuli
◦Inflammation of bronchial walls
◦Increased mucus secretion
asthma
symptoms of asthma include
- recurrent wheezing, shortness of breathe/chest tightness, cough
- more frequent at night/early morning
atopic asthma
type I (IgE-mediated) hypersensitivity reaction
usually onset in childhood
atopic asthma is triggered by
pollen
animal dander
dust
food
Patients may have high serum IgE, a positive skin test for the
inciting allergen, or may demonstrate IgE antibodies to
specific allergens, and often have a family history of it
atopic asthma