week 5: respiratory pathology Flashcards
what is a pulmonary disease
- diseases that cause airflow blockage and breathing related problems
what is the differnce between an obstructive and restrictive disease?
obstructive: can get air in, stuggle to get it out
- air flow limitation
- partial/complete blockage
- abnormal narrowing
- loss of elastic recoil
- decrease of max respiratory airflow (decrease FEV)
- eg. emphysema, chronic brochitis, asthma
restrictive: can’t get air in
- decreased expansion of lung parenchyma
- decreased total lung capacity
-acute and chronic infiltrative diseases: (pulmonary oedma, RA, intertestial lung disease)
- chest wall conditions: neuromuscular diease: polio, kyphoscoliosis, RA
describe emphysema
- abnormal/permenant enlargement of airspaces distal to terminal bronchioles, and destruction of alveolar walls
what is the cause?
- smoking (majority)
- people born with antitryspin deficiency
emphysema develops when there is an imbalance between:
oxidant + protease: anti-oxidants, anti-protease
- destruction of alveolar walls and enlargments of airspaces develops
pathophysiology of emphysema
- tobacco smoke
- inflammatioon fo airway epithelium
- infiltration fo inflammatory cells
- break down of luncg elastic tissue
- emphysema (destruction of alveolar septa and loss of elastic recoil fo bronchial walls)
- resulting in airway obstruction, air tapping, loss of gas exchange, infection
what is air trapping in Emphysema?
when air become trapped in distant airspaces, making it hard to push air out due to:
- inflammation and fibrosis in airways
- loss of elastic recoil
- loss of tethering in airways
- increase of smooth muscle and bronchspasm
- airways becoming floppy and collaspsing
- loss of elastic recoil leading to decreased flow
how do bullae develop with emyphysema?
- they are air filled spaces within the lungs that take up/waste areas of lungs
what do X-RAys look like when people have emphysema?
- less lung tissue: this shows up black
- can see “bubbles” which are enlarged bullae
- larger luncgs with low set diaphragms
emphysema symptoms
- progressive dyspnoea (shortness fo breath)
- hunched over (kyphosis)
- increased work of breathing rate
- pursed lip breathing (prolongs repiritory phase and opens airways)
- barrell chested/hyperinflated
- cough/wheeze
- weight loss and muscle atrophy
- less lung chest tissue at front
how does emphysema lead to death?
symptoms may not manifest until 1/3 of lung parenchyma is damged
death can result from
- respiratory failure
- right sided failure
- pneumothorax (air outside the lung)
describe chronic bronchitis
- persistant cough with sputum production fro at least 3 months in at least 2 consecutive years (in absense of other causes)
- chronic inflammation by inhaled smoke (90% ciggarette)
- when there is a hypersecretion of musus in large airways
- marked increase of goblet cells of small airways
define goblet cell
- modified epithelial cells that secrete mucus on the surface of mucous membranes of organs
- particularly those of the lower digestive tract and airways
functions of ciliated epithelial cells and how does this change with chronic bronchitits
form a mucocilliary escalator:
- layer of fluid and mucins lining the peipthelium function to clean the airways by moving mucous continuously from lower respiritory tract
interferes with cililary actions:
- nicotine induces expression of epidermal growth factors in ciliated cells (metaplasia)
- shortens cilia, and decreases beat frequency
- disruption to genes of epithelium
- less hydration of mucous
- slows cilial regeneration
other morphological changes of chronic bronchitits
hyperplasia of muscous secreting glands and incease of goblet cells in airway epithelium
- more mucous
- thicker mucous
- easier to colonise
bronchial walls inflammed and thickened
inhibited availabiloyt of bronchial and alveolar leukocytes
cilial function impaired
pathophysiology of chronic bronchitis
- tobacco smoke
- inflammation of airway epithelium
- infiltration fo inflammatory cells and release of cytokines
- continuous brachial irritation and inflammation
- chronic bronchitis (bronchial edema, hypersecretion of mucus, bacterial colonisation of airways)
- resulting in airway obstruction, air trapping, loss of gas exchange, infection