respiratory system Flashcards
describe homeostatic functions of the lung. (4)
- gas exchange occurs…
- between atmosphere and blood to provide oxygen to tissues and remove CO2 generated in oxidative metabolisation
O2 + food =CO2 = HO2 +APT
- regulates body PH by
retaining or eliminating CO2
- controls blood pressure
through the conversion of angiotensin 1 to angiotensin 2
airflow occurs by
bulk flow
airflow occurs by
bulk flow i.e.
high pressure to low pressure
(1r to the 4th power)
F=(P1-P2)/R
lung connected to chest wall by
pleura
describe conducting zone (4)
- leads from outside body to inside lungs
- nasal cavity, pharynx, trachea, bronchus and bronchioles
- total volume 150ml
- anatomical dead space
respiratory zone
- gas exchange
- bronchioles, alveolar ducts, alveoli
- 3 litre volume
3 types of cells in lungs
TYPE 1- thin epithelial cells that line 90% of alveoli surface area. gas diffuses across these cells and into blood
TYPE 2- synthesise, secrete and metabolise alveolar surfactant, a lipid rich substance that prevents lungs from collapsing
ALVEOLAR MACRROPHAGES - the clean-up cells, attracted to infection, trauma or inhaled particles
PA
pressure in alveoli
Patm
atmospheric pressure
pressure in breathing
air flows into the mouth until PA=Patm
normal ventilation rate
10-18 breaths per min
ventilation rate controlled by
medulla oblongata
FRC
functional residual capacity
resting volume of lung and chest wall 2.5 litres