Respiratory system Flashcards
Anatomy of right lung
Wider and shorter than left
3 lobes - superior, middle, inferior
2 fissures - oblique, horizontal
Anatomy of left lung
Narrower and longer than right
2 lobes - superior and inferior
1 fissure - oblique
Pleural cavity
Visceral pleura - covers lung Parietal pleura - lines chest wall Hilum > reduces friction creates a pressure gradient to assist ventilation isolates lungs
Upper respiratory tract
Nose, nasal cavity, paranasal sinuses, pharynx, larynx
Lower respiratory tract
Trachea, bronchi, bronchioles, alveoli
Conducting zone
nose, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles
- filters, warns and moistens air
- transmits air to and from lungs
Respiratory zone
respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
- site of gas exchange
Nasal cavity
Warms, cleanses and humidifies air Detects odours Resonating chamber that modifies voice Conchae Meati Paranasal air sinuses
Pharynx
Extends from nose to larynx
Passageway for airway and food
Warms and humidifies air
Resonating chamber for speech sounds
Larynx
9 pieces of cartilage Maintains an open airway Switching mechanism: - swallowing - larynx in pulled upwards, epiglottis moves down to cover laryngeal inlet - cough reflex Changes tension in vocal chords
Trachea (+oesophagus)
Cartilage rings
Smooth muscle
Respiratory mucosa
Muco-ciliary escalator
Cilia in upper respiratory tract move mucus down towards pharynx
Cilia in lower respiratory tract move mucus up towards pharynx
Bronchial tree
Trachea - primary bronchi - secondary bronchi - tertiary bronchi - bronchioles - terminal bronchioles
Difference between bronchus and bronchioles
Bronchus have cartilage in their walls
Alveoli
Type I alveolar cell = squamous epithelium
Type II alveolar cells = septal cells
- gaseous exchange
Blood supply to lungs
Pulmonary arteries carry blood to be oxygenated
Pulmonary veins carry oxygenated blood from lungs to the heart
Bronchial arteries supply lung tissue with blood, arise from the aorta and branch with bronchi (don’t supply alveoli)
Intrapulmonary pressure: inspiration
- Diaphragm and external intercostal muscles contract
- rib cage moves up and outwards
- thoracic cavity volume increases
- intrapulmonary volume increases
- intrapulmonary pressure decreases
- air enters lungs down pressure gradient until intrapulmonary pressure = atmospheric pressure
Intrapulmonary pressure: expiration
- diaphragm and external intercostals relax
- rib cage moves in and down
- thoracic cavity volume decreases
- intrapulmonary volume decreases
- intrapulmonary pressure increases
- intrapulmonary pressure > atmospheric pressure = air leaves lungs down a pressure gradient until intrapulmonary pressure is 0
Pulmonary compliance
Ease with which the lungs expand Healthy lungs are stretchy = high compliance Compliance is reduced by: - scar tissue - difficulty in expanding lungs - blockages - low levels of surfactant
Partial pressure
The pressure exerted by each gas.
Directly proportional to its percentage in the total gas mixture
Henry’s law
“amount of gas that dissolves in water is determined by its solubility in water and its partial pressure in air”
solubility in plasma = carbon dioxide > oxygen»_space;nitrogen
Detection systems
Peripheral chemoreceptors > aortic bodies > carotid bodies (main O2 sensors) Central chemoreceptors - monitor pH of CSF
