The Lung Flashcards
Upper airway
Nasal cavity, nasopharynx, oropharynx
Not close to airway
Lower airway
Larynx, trachea, bronchi, bronchioles, alevioli
Closer to blood supply
Functional - only air is transported (nasal cavity -> terminal brochiole)
Respiratory zone (16-17)
Resp bronchiole -> alveoli
Risk of infection
Respiratory epithelium
Pseudostratified ciliated columnar epithelium + goblet cells + stem/basal cells
Nasal hair - vibrissae
Filter
Air swished/swirled
Particles captured by mucus
Moved to the pharynx by cilia
Mucociliary escalator
Warming the air
Water exchange
Trachea epi
Pseudostratified columnar epithelium
Bronchus epi
Columnar ciliated
lower bronchus epi
cuboidal ciliated
respiratory bronchioles
don’t have cilia
Bronchi/Trachea
Cartilage - open
Defense
Glands - mucus
Goblet cells
Ciliated
Bronchioles
Flow
Ciliated cuboidal epithelium
Club cells - club cell secretion (anti inflam)
Smooth muscle
Pneumocyte type I cell
Cover 95% surface area in squamous. Ideal for gas exchange
Pneumocyte type II cell
Secret surfactant - a liquid lining
Reduce surface tension inside alveoli
Less work for breathing
Premature birth
Surfactant unsufficient
Pneumonia
fluid/pus in airway
COPD
Chronic obstructive pulmonary disease
Decrease elastic fibres and alveoli space (SA)
Hilum
Where bronchi and pulmonary vessels enter and exit
Stages of Lung development - 26 days to 7 week
(embryonic)
Lung bud arises as ventral outpouching and undergoes 3 round of branching, producing the primordia of the two lungs, lung lobes and bronchopulmonary segments
Stages of Lung development - 5 to 17 week
(pseudoglandular)
Respiratory tree undergoes more generations of branching, resulting in formation of bronchi, bronchioles and terminal bronchioles. Lung resembles a gland
Stages of Lung development 16-25
(cancalicular)
Each terminal bronchiole gives rise to 2 or more resp bronchioles. Each divides into 3-6 alveolar ducts lined by cuboidal cells.
Stages of Lung development - 24 week to after birth
(saccular)
Alveolar ducts give rise to thin walled terminal air sacs. Type I alveolar cells are intimately associated with blood and lymph capillaries. Type II alveolar cells develop and begin to produce surfactant.
Stages of Lung development - Late foetal to 8 years
(alveolar)
Number of terminal sacs increases. Alveoli mature through continued thinning of squamous epithelial lining and more intimate contact with surrounding capillaries
Respiratory Distress Syndrome
32 weeks-term: good survival
<24-28 weeks: poor survival
Hard to inflate lungs - limited surfactant
Glucocorticoids to mother in labour
