Normal lung histology and pathophys of COPD Flashcards
3 components of the upper resp tract
nasal cavity
pharynx
larynx
3 components of the lower resp tract
trachea
bronchi and bronchioles
alveoli
3 roles of the nasal cavity and pharynx
cleans
humidifies
warms air
2 roles of larynx
phonation
protection
what cells line the nasal cavity and nasopharynx
columnar ciliated (respiratory) epithelium
5 cell types found in the respiratory epithelium and function
Goblet cells- secrete mucus which traps particulate matter
Ciliated cells- moves mucus towards the oropharynx to be swallowed
submucosal seromucinous glands- Produce mucus and secrete watery fluid which helps to humidify air
blood vessels- warm air
lymphoid tissue- protect against inhaled pathogens
type of epithelium in the oro and hypopharynx
stratified squamous epithelium
how do the bronchioles differ from the trachea and bronchi
no cartilage in walls and no mucinous glands
what lines the trachea and bronchus?
ciliated columnar (respiratory) epithelium
2 component cells in the mucociliary escalator
goblet cells
ciliated cells
What cells line the alveoli?
pneumocytes
describe type 1 and type 2 pneumocytes
T1: large flattened cells- thin diffusion barrier
T2: secrete surfactant
define COPD
airflow obstruction that is usually progressive, not reversible, and does not change markedly over several months. Characterised by an abnormal inflammatory response in the lungs
what is emphysema
enlargement of the airspaces distal to the terminal bronchiole and destruction of alveolar walls.
3 pathophysiological features of chronic bronchitis
mucous gland hyperplasia- hypersecretion of
mucus
squamous metaplasia of lining of airway
defective mucociliary clearance
what 3 things contribute to the development of small airway disease/bronchiolitis and what does this lead to
mucus plugging
impaction of particles
inflammation
leads to…
scarring and fibrosis
narrowing and loss of small airways
impaired gas exchange
how does smoking cause emphysema?
particles in small airways increase inflammatory cells (macrophages and neutrophils)
release of damaging substances e.g. elastases
release of oxygen free radicals which reduce the effectiveness of protective enzymes e.g. alpha 1 antitrypsin
both lead to destruction of normal elastic in the lung
5 complications of COPD
resp failure pneumonia pulm HT and cor pulmonale pneumothorax polycythaemia (2y)
Describe type 1 resp failure
“pink puffers”
good alveolar ventilation,
PaO2<8kPa
N or low PaCO2
breathless not cyanosed
describe type 2 resp failure
“blue bloaters”
poor alveolar ventilation Pa02 <8kPa PaCO2 >6.5kPa cyanosed require hypoxic drive to stimulate breathing
3 ways smoking increases risk of infection
affects normal ciliary action
damages epithelium
damages normal inflam cells
5 complications of pneumonia
pleural effusion empyema abscess bronchiectasis dissemination of infection to adjacent organs and/or other parts of the body
