Respiratory Physiology Flashcards
What are the 3 different zones in the respiratory tract, and their components?
- Upper respiratory tract
- nasal and oral cavities
- pharynx
- larynx - Lower respiratory tract (conducting zone)
- trachea
- bronchi and bronchioles (excepting respiratory bronchioles) - Lower respiratory tract (respiratory zone)
- respiratory bronchioles
- alveolar sac and alveoli
What are the different areas of the pharynx?
Nasopharynx (behind nose)
Oropharynx (behind mouth)
Laryngopharynx (behind larynx)
What are the epithelial types in the conducting zone of the respiratory tract?
Trachea and bronchi:
- psuedostratified ciliated columnar epithelium
Terminal bronchioles:
- cuboidal epithelium
Alveoli:
- squamous epithelium
Which parts of the respiratory tract have cartilaginous walls?
Trachea: cartilaginous rings
Bronchi: irregular cartilaginous plates
Bronchioles: no cartilage (elastic fibres provide structure)
What is the respiratory membrane?
The membrane between alveoli and capillaries where gas exchange occurs
- formed by the fused basement membranes of the squamous epithelial cells of alveoli and capillaries
What are the 2 types of alveolar cells?
Type 1:
- squamous epithelium
- most of alveolar wall
Type 2:
- cuboidal epithelium
- secrete surfectant that reduces the surface tension of alveolar fluid
How does gas exchange occur at the respiratory membrane?
O2 and CO2 are both lipid soluble and diffuse directly through respiratory membrane (moving from area of higher concentration to area of lower concentration)
What is respiration?
The processes involved in supplying the body with oxygen and disposing of carbon dioxide
What are the 4 components of respiration?
- pulmonary ventilation (inspiration and expiration)
- external respiration (exchange of gases at the respiratory membrane)
- gas transport
(movement of gas through the bloodstream) - cellular respiration
(aerobic metabolism within cells)
What are the 3 pressures in the lungs?
- Intra-pulmonary / intra-alveolar
- pressure within the alveoli
- decreases in inspiration (as alveoli expand)
- increases in expiration (as alveoli contract) - Intrapleural
- pressure within pleural cavity
- always negative to intrapulmonary pressure (so that lungs are coupled to thoracic wall) - Transpulmonary
- difference between intrapulmonary and intrapleural pressures
What is Boyle’s Law?
Pressure decreases when volume increases, and vice versa
How does Boyle’s Law work in inspiration?
- Tx cage expands and volume increases
- intrapulmonary pressure decreases as alveoli expand
- air flows into lungs (area of lower pressure) until intrapulmonary pressure equals atmospheric pressure
How does Boyle’s Law work in expiration?
- Tx cage constricts and volume decreases
- intrapulmonary pressure increases as alveoli constrict
- air flows out of lungs (from higher pressure to lower atmospheric pressure) until intrapulmonary pressure equals atmospheric pressure
Which factors affect the body’s ability to achieve ventilation?
- Lung compliance
(ability of lungs to expand)
- incapacity of Tx cage to expand - Airway resistance
- restriction, occlusion or resistance to air flow within respiratory tract
What are examples of restrictive pulmonary disease (lungs unable to expand)?
Intrinsic:
- pneumonia
- cancer
Extrinsic:
- pleural effusion
- obesity
- scoliosis / kyphosis