The respiratory system Flashcards
How does the respiratory system develop?
- As a diverticulum from the pharynx
What are the functions of the nasal cavity?
- Induce turbulent flow (nasal conchae)
- Warm and moisten inspired air (allows gases to dissolve)
- Recover water from expired air
- Phonation
- Olfaction
What do nasal conchae do?
- 3 outgrowths on medial surface of nasal cavity
- Increase surface area for inspired air to be moistened and warmed on way in and cooled down on way out
Outline the structure of the nasal cavity
- Enters through nostrils and passes into nasal vestibule (lined by keratinised stratified squamous epithelium)
- Nostrils are lined with nasal hair, which filter dust and other foreign materials
- Epithelium then changes to ciliated pseudostratified columnar epithelium
What are ostia?
- Small orifices that connect paranasal sinuses to the nasal cavity
- Can become blocked if inflamed
How many paranasal sinuses do we have?
- 4 (frontal, sphenoid, ethmoid, maxillary)
What are the 3 sections of the pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
What are the conducting airways of the respiratory system?
- Trachea
- Primary bronchi
- Secondary bronchi
- Tertiary bronchi
- Bronchioles
- Terminal bronchioles
What make up the walls and floor of the thoracic cavity?
- Ribs and costal cartilages make up walls
- Diaphragm makes up floor
Which surfaces articulate with the ribs?
- Vertebrae (articular facets articulate with thoracic vertebrae)
- Sternum
Which bones make up the sternum?
- Manubrium
- Body
- Xiphoid process
What is the mediastinum?
- Septum between lungs
What allows ventilation?
- Movement of joints between ribs and vertebrae
What is meant by the bucket handle movement?
- Need to increase volume in thorax for ventilation to occur
- Need to increase lateral aspect of chest
- Bucket handle movement allows this
- Rib = bucket handle
What is meant by the pump handle movement?
- Sternum moves upwards and anteriorly
- Increases anteroposterior dimension of chest
What happens to the diaphragm on inhalation?
- Diaphragm moves down at least 2 intercostal levels
How do movements of the ribs cause movement of air into the lungs?
- Alveolar pressure must be lower than atmospheric pressure of air to enter alveoli
Where must drains be inserted into the thoracic cavity?
- Must insert above each rib
- Otherwise nerve damage occurs
- Neurovasculature arranged in major bundle below each rib and minor bundle above each rib
What is the innervation of the diaphragm?
- Phrenic nerves
- C3, C4, C5
What are the muscles of ventilation?
- External intercostal muscles (fibres run in antero-inferior direction)
- Internal intercostal muscles (fibres run perpendicular to external intercostal muscles)
- Innermost intercostal muscles (bigger role in forced expiration)
At what level does the vena cava pass through the diaphragm?
- T8
At what level does the oesophagus pass through the diaphragm?
- T10
At what level does the aortic hiatus pass through the diaphragm?
- T12
What are the accessory muscles of respiration?
- Sternocleidomastoid
- Scalenus anterior, medius, and posterior,
- Pectoralis major and minor
- Inferior fibres of serratus anterior and latissimus dorsi
