Anatomy ✅ Flashcards
What is the respiratory system split into?
Three major parts-
- Upper airways
- Conducting airways
- Lower respiratory tract
How do the upper and conducting airways differ at birth compared to in an adult?
The upper and conducting airways are fairly well developed, but smaller and the relative size of the component parts is different, e.g. the epiglottis is relatively large and floppy
How does the lower respiratory tract differ at birth compared to in an adult?
It is significantly different from the adult constitution, with far fewer alveoli and proportionally more conducting airways
What is the upper airway made up of?
- Nasal cavity
- Sinuses
- Pharynx
- Larynx
What lines the entire upper airway and conducting airways?
Ciliated (respiratory) epithelium
What do abnormalities of the cilia lead to?
Blockage and obstruction
Why do abnormalities of the cilia lead to blockage and obstruction?
As these are required to ensure clearance of mucus
What are the main functions of the nasal portion?
- Filtration
- Humidification
- Warming
What size of particles tend to impact in the upper airway?
10µm or larger in diameter
What temperature is the air reaching the trachea?
6-30 degrees
What does the temperature of the air reaching the trachea depend on?
- Minute ventilation
- Size of the child
- Ambient temperature
What happens to heat from gases expired through the nose?
It is extracted by use of a countercurrent exchange system
What can cause loss of control of the pharyngeal muscles?
- Pathology, e.g. cerebral palsy, muscular dystrophies
- Deep sedation
What does loss of control of the pharyngeal muscles lead to?
Intermittent upper airway obstruction (stertor)
What does narrowing at the larynx lead to?
Fixed upper airway obstruction (stridor)
When is the airway maximally open in babies?
When the head is held in a neutral position
What happens to the position in which the airway is maximally open as the relative size of the head decreases?
It becomes maximally opened with increasing degrees of neck extension
What are the conducting airways made up of?
Trachea, bronchi, bronchioles that make up the first 16 branches of the tracheobronchial tree
What is an important constituent of the larynx and conducting airways?
Cartilage
How does the cartilage of the larynx and conducting airways compare at birth to in an adult?
it is significantly more floppy
What does the trachea divide into?
Two bronchi
How does the right bronchi compare to the left bronchi?
The right bronchi is wider and more vertical
What is the result of the right bronchi being wider and more vertical?
Inhaled objects tend to fall into the right main bronchus
What do the bronchi divide into?
Four lobar bronchi
What do the lobar bronchi divide into?
16 segmental bronchi
What is reached after 16 subdivisions of the lobar bronchi?
The terminal bronchioles
What are the terminal bronchioles capable of?
Limited gas exchange
What are the lower airways made up of?
Divisons 16-23 of the airways
What happens in the lower airways?
Most gas exchange
Is the formation of the lower airways complete at birth?
No, only partially complete
What is alveolarisation?
The formation of new alveoli
When does alveolarisation take place?
Until at least 2 years of age
What are the lungs surrounded by?
Visceral pleura
What are the thoracic walls and upper surface of the diaphragm covered by?
Parietal pleura
What separates the visceral pleura and parietal pleura?
A thin layer of pleural fluid
Why do the layers of pleura usually remain closely opposed?
Due to the considerable surface tension that exists
Can the layers of pleura side over each other?
Yes, easily
What can cause fusion of the layers of pleura?
Production of fibrin
What does fusion of the layers of pleura by production of fibrin lead to?
Pain on movement (pleurisy)
What can cause separation of the pleura?
- Fluid (pleural effusion)
- Gas (pneumothorax)
What can separation of the pleura lead to?
Pain, particularly on inspiration
