Respiratory System 2 Flashcards
Where are club cells?
In the wall of a bronchioles
Does a bronchus or a bronchioles have smaller diameter?
Bronchioles (and is also more simple)
Describe the bronchioles?
Smooth muscle controls the diameter, causes resistance of air and during exercise, there’s increased volume and decreased resistance to airflow as relaxed smooth muscle
What happens in an asthma attack?
Constriction of smooth muscle, but a bronchodilator relaxes smooth muscle
What’s in the wall of the bronchus?
Goblet cells, pseudostratified ciliated columnar epithelium, smooth muscle, mucus glands, cartilage plate
Is alveoli part of a bronchus?
No
What’s in a bronchiole wall?
Club cells, columnar ciliated epithelium, smooth muscle
What is the last bronchiole in the conducting zone?
Terminal bronchiole
Where do alveoli branch off from?
The bronchiole wall
What are alveoli sacs?
Bunches of alveoli
What are alveolar ducts?
Tubes made up of alveoli
What’s wrapped around a single alveolus?
Capillaries
What does the surfactant do?
Keeps alveoli moist, stops alveoli collapsing when you exhale
What’s the diffusion barrier in the alveolar wall like?
Alveolar air space Squamous pneumocyte Basement membrane sq. pn fused to basement membrane cap. End Cap. Endothelium Blood plasma Red blood cell
What supports the large airway during inspiration, but doesn’t continue beyond the smallest bronchi?
Cartilage (mucous glands also stop there too)
When does the thickness of the decrease?
When airway diameter decreases
Where are secretory cells?
In the epithelium of conducting airways
What are the types of secretory cells?
Goblet cells (mucus in larger airways) and club cells (serous-watery secretion in bronchioles)
Where is there more spiral orientation smooth muscle in relation to its size?
In small airways- although this muscle coat doesn’t continue beyond smallest bronchioles
What are the primary bronchi?
Right and left main stem bronchi supplying each lung
What are the secondary bronchi?
Lobar bronchi supplying lobes (2 on left, 3 on right)
What are tertiary bronchi?
Segmental bronchi supplying segments of the lung (8 on the left, 10 on the right)
What does each segment of the lung have?
It’s own air and blood supply
What does segmental air and blood supply mean for a surgeon?
When a localised tumour occurs, a surgeon who knows approximate boundaries can remove one or more segments containing the tumour without excessive leakage of air or blood from neighbouring segments
How many bronchopulmonary segments are there?
10
What is a pleura?
A smooth membrane covers each lung and lines the thoracic cavity in which the lung sits
Where are the pleurae continuous at?
The root of the lung (hilum)
What separates the pleurae and what does it allow for?
A thing film of fluid, which allows the pleurae to slide past each other without friction but also prevents them from separating
What must happen when the thoracic wall moves inwards/outwards or the diaphragm moves upwards/downwards?
The lungs must follow
Layers of the pleura? (In-out)
Visceral pleura
Pleural space (pleural fluid)
Parietal pleura
Muscles of ribs
What is responsible for 25% of air movement into and out of the lungs?
Movement of the ribcage
What is inspiration?
Active and requires contraction of the external intercostal muscles which run obliquely between ribs
What is expiration?
Passive as the ribcage returns to its resting position without requiring muscular action
What is breathing like during exercise?
Both sets of intercostal muscles are now active; external for inspiration, internal for expiration
What does external intercostal muscle contraction do to the ribs ?
Lifts them up (rotating them around their pivot points)
What does the ribs lifting and swinging upwards and outwards do?
Increases the volume of the thorax movement
What does internal intercostal muscle contraction do to the ribs?
Drags them downwards- but active contraction only occurs during forceful exhalation
