respiratory system:-

process where living organism meet their oxygen requirement

types:-

external and internal respiration:-

function :-

I)provide o2 to body and exclusion of co2

regulation of body temprature

act as supplementary excretory organ

regulation of o2

regulation co2

synthesis of angiotensin converting enzyme ,surfactant, serotonin.

Conductory zone	Respiratory zone
From 1-6 generation	From 17-23 generation
Lies between nasal cavity to terminal bronchioles	Respiratory Bronchioles to alveoli
Made up of c shaped cartilage	Takes part in gaseous exchange
Cilia and mucous secreting cells they trap dust and microbes	Absent,made up of thim epithelium
Surface area 2-5 cm 2	70 cm 2

Alveoli:-structural and functional unit of lungs ,covered by thin squamous epithelium

Type 2 cells -produce surfactants and prevent collapse of alveoli

Inspiration 2 sec

Expiration 3 sec

Dead space:- the part respiratory zone which not take part in gaseous exchange

Normal 150 ml -30% of tidal volume.

Type 1)anatomical dead space:-parts of respiratory space that doesn't involve in gaseous exchange due to c shaped cartilage

-from nasal cavity to terminal bronchiole

-150 ml normal value

Physiological dead space;-

PDS =ADS +alveolar DS

-in normal conduction PDS=ADS

-in pulmonary disease pds greater than ads

To find ADS single breath n2 washout technique.

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