Pulmonology Flashcards
Which anatomical structures are considered part of the upper respiratory tract (URT)? (3)
- Nose
- Sinuses
- Pharynx
Into which three parts is the pharynx subdivided?
- Nasopharynx
- Oropharynx
- Hypopharynx
Which anatomical structures are considered part of the lower respiratory tract? (LRT) (4)
- Larynx
- Trachea
- Bronchus/bronchioli
- Lung
What kind of epithelium can be found in the trachea?
Respiratory epithelium -> cilindrical ciliated epithelium
What is the shape of cartilage bands in the trachea?
C-shaped
What is the opening in the C-shaped cartilage bands in the trachea filled with?
Smooth muscle tissue connecting both sides of the C-shape
How many generations of branching can be found in the bronchial system?
~24
Into which two regions can the bronchial system be divided?
- Non-respiratory
- Respiratory
Which bronchi & bronchioli are part of the non-respiratory bronchial system? (3)
- Bronchus
- Segmental bronchioli
- Non-respiratory subsegmental bronchioli
What is the size cut-off between a bronchus and a bronchiolius?
Bronchus >1 cm, bronchiolus <1 cm
Which structures are part of the respiratory bronchial system? (3)
- Respiratory subsegmental bronchioli
- Alveolar ducts
- Alveolar sacs
Into how many segments is the left/right lung divided?
Left = 9
Right = 10
Which cell types can be found in the bronchus? (5)
- Cylindric ciliated epithelium
- Goblet cells
- Basal cells
- Neuro-endocrine cells
- Club cells
What is the function of the cilia of respiratory epithelium?
Beat to remove particulate matters from the respiratory tract
What is the beating frequency of the cilia of respiratory epithelium? What does this frequency depend on?
~20x/second, depending on outside temperature (lower = slower)
What is the function of goblet cells?
Production of mucin
Where is most mucus in the respiratory tract produced?
Bronchial glands
What is the function of basal cells in the respiratory tract?
Stem cells for respiratory epithelium
How are basal cells connected to the basal lamina?
Hemi-desmosomes
What is the function of neuro-endocrine cells in the respiratory tract?
Important in the development of the lungs
Neuro-endocrine cells are present in [low numbers/high numbers] in healthy situations. During inflammation, their number [decreases/increases]
Healthy: low numbers
Inflammation: increase of neuro-endocrine cells
How can neuro-endocrine cells be visualized during histology?
Immunohistochemical staining
In which bronchi can club cells be found?
Smaller bronchioles
What are the functions of club cells? (4)
- Modulation of inflammatory reactions
- Metabolism of inhaled toxic substances
- Surfactant production
- Stem cells for ciliated/mucous cells
Squamous epithelial cells [are/are not] present in healthy respiratory tracts
Not present; presence of squamous epithelium = metaplasia
Where in the respiratory tract can bronchial glands be found?
Medium-sized bronchioles, large bronchioles & bronchi
Why is it harder to move mucus higher up in the respiratory tract, compared to the smaller structures deep in the respiratory tract?
Lower surface area = less cilia to move mucus
Which system influences the density of mucus in the respiratory tract?
CFTR ion transporter
Mucus consists of two-layers with different viscosity. What is the lower layer called, and is it more or less viscous than the upper layer.
Hypophase -> less viscous than upper layer, allowing cilia to move
What is the functional unit into which the lungs are divided? How is this determined?
Pulmonary acini/primary pulmonary lobule -> this is the area originating from 1 respiratory bronchiole
How many alveoli does a pulmonary acinus contain on average?
~2000
What is the smallest identifiable component of the lung? How is this determined?
Lobule/secondary pulmonary lobule -> the area originating from 1 terminal bronchiole (=bigger than acinus!)
How many acini does a lobule contain?
3-30
How are alveoli connected in the lung? What is their physiological function? Why are they important for pathology?
Pores of Kohn form connections between the alveoli
Physiological function: allow air to pass between alveoli in case of obstructions
In a pathological setting, pathogens (bacteria) can use these pores to spread throughout a whole lobe of the lung
Which two cell types can be found in the alveoli of the lung?
- Type I pneumocyte
- Type II pneumocyte
What is the function of type I pneumocytes?
Gas exchange (thin cells that allow for diffusion)
What are the functions of type II pneumocytes? (2)
- Surfactant production
- Replacement of damaged type I pneumocytes
Which type of pneumocyte covers the majority of the surface of the alveoli? How many % of the surface?
Type I pneumocyte, 95%
Which is more abundant: type I pneumocyte/type II pneumocyte
Type II pneumocyte (even though type I pneumocytes cover the majority of the surface)
In addition to cells, which structure can be found in the alveoli?
Interstitium
Which immune cells can be found throughout the alveoli of the lung?
Alveolar macrophages
Which staining is used to visualize connective tissues in the lung?
Elastica van Gieson (EvG)
What are age-related normal changes of the lungs? (9)
- Ossification of tracheal/bronchial cartilage
- Epithelial metaplasia in bronchial glands
- Pulmonary arterial/venous intimal thickening
- Alveolar enlargement = senile emphysema
- Medial calcification in bronchial arteries
- Senile vascular amyloidosis
- Anthracosis
- Pleural plaques
- Apical cap
What makes the lung easy to enter for pathogens? (2)
- Large interface with the environment
- Highly vascularized, allowing blood-borne pathogens to enter
Which stainings are used to identify bacterial infections of the lung? (3)
- Gram
- PAS
- Ziehl-Neelsen/auramine
What do Ziehl-Neelsen/auramine stainings reveal?
Mycobacteria
Which stainings are used to identify fungal infections of the lung? (3)
- PAS/PAS-D
- Grocott
- Immunohistochemistry
Which staining can be used to identify viral infections of the lung?
Immunohistochemistry
What are conditions that predispose for infections of the lung? (4)
- Impairment of pulmonary defence mechanisms
- Lowered host resistance
- Unusually virulent pathogens
- Being hospitalized
Which defence mechanisms are present in the respiratory tract? (4)
- Clearing mechanisms -> coughing, sneezing
- Mucociliary apparatus
- Phagocytic/bactericidal action
- Oedema/congestion
What kind of respiratory infections are often abundant in case of defects of innate/humoral immunity?
Pyogenic infections
What kind of respiratory infections are often abundant in case of defects of cellular immunity?
Intracellular organisms & low-virulent organisms
Viral pneumonia is often [self-limiting/severe/deadly]
Often self-limiting
What often happens when a viral pneumonia becomes very severe?
Bacterial superinfection
Into which major groups can viral infections of the respiratory tract be divided? (3)
- Specific/restricted to respiratory tract
- Systemic infections involving the lung
- Opportunistic infections
What are viruses targeting the URT? (5)
- Rhinovirus
- Coronavirus
- Influenza virus
- RSV
- Adenovirus
What are viruses targeting the LRT? (4)
- Influenza virus
- RSV
- Adenovirus
- Metapneumovirus
Systemic infections by which viral families can also cause respiratory symptoms? (3)
- Herpesviruses
- Paramyxoviruses
- Togaviridae
True or false: viral respiratory inections can by easily distinguished through histology
False; limited morphological specificity in viral pulmonary infections
Which histological pattern is often seen in viral infection of the lung?
Interstitial lymphocytic pattern with diffuse alveolar damage
What is sarcoidosis (definition)?
Granulomatous disorder of unkown cause, affecting multiple organs
Why is sarcoidosis difficult to diagnose?
It can resemble many other diseases
Which locations of sarcoidosis often have most severe complications? (2) Does sarcoidosis often occur in these areas?
- Heart
- CNS
Sarcoidosis in these locations is rare
Which organs are most often affected by sarcoidosis? (3) What is a common factor between these organs?
- Lung
- Skin
- Eyes
All three exposed to outside air
What is the M:F ratio of sarcoidosis?
1:1
Men are often affected by sarcoidosis at an [older/younger] age, whereas women are affected [older/younger]
Men = younger
Women = older
How many % of sarcoidosis cases resolves itself, and how many % become chronic?
50/50
What is an acutely presenting form of sarcoidosis? Where does it often occur?
Löfgrens syndrome, often occurs in Scandinavia
What is the prognosis of Löfgrens syndrome?
Good prognosis
What is the treatment strategy of low-risk sarcoidosis?
Observe, treat when necessary
How many patients within a low-risk group of sarcoidosis go into remission within 2 years?
60-70%
What is the treatment strategy of intermediate-risk sarcoidosis?
Treat with low dose glucocorticoids, but try to maintain best quality of life
How can treatment of intermediate-risk sarcoidosis be escalated, if needed?
DMARDs or anti-TNF
What is the treatment strategy of high-risk sarcoidosis?
Aggressive treatment using high dose corticosteroids with methotrexate
What is the hallmark of sarcoidosis?
Granuloma formation
What is the structural makeup of a granuloma?
Core of histiocytes (=macrophages), surrounded by fibroblasts & T-cells
When do granulomas normally form?
When a foreign object cannot be cleared by the immune system and needs to be encapsulated
What is the disadvantage of using anti-inflammatory treatments in case of granulomatous disease?
It could reactivate disease (such as tuberculosis) that is encapsulated in these granulomas
What is the antigen causing granuloma formation in sarcoidosis?
Antigen unknown
How many % of affected individuals die due to progressive sarcoidosis?
1-5%