Breathing and Exchange of Gases
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Each terminal bronchiole gives rise to many very thin irregular walled
and vascularized alveoli (in lungs).
A cartilaginous Larynx (sound box or voice box) helps in sound
production.
During swallowing, epiglottis (a thin elastic cartilaginous flap) closes
glottis to prevent entry of food into larynx.
Trachea divides in the region of the 5th thoracic vertebra C-shaped.
Trachea, all bronchi and initial bronchioles are supported by incomplete
cartilaginous half rings of hyaline cartilage.
[NEET 2013]
2. LÜÑGS
Situated in thoracic chamber.
The thoracic chamber is found dorsally by the vertebral column,
vertically by sternum, laterally by the ribs and on the lower side by the
dome shaped diaphragm.
The anatomical setup of lungs in thorax is such that any change in the
volume of the thoracic cavity will be reflected in the lungs cavity.
Right lung has 3 lobes and left lung has 2 lobes.
Lungs are covered by double-layered pleura (outer parietal pleura
in closed contact with the thoracic lining and inner visceral pleura in
contact with the lungs surface).
[AIPMT 2005]
The pleural fluid present in between these 2 layers lubricates the surface
of the lungs and prevents friction between the membranes.
Lungs= Bronchi + bronchioles + alveoli.
Respiratory or exchange part: The site of actual diffusion of O2 and CO2
between blood and atmospheric air (alveoli and their ducts).
Alveoli are the structural and functional units of lungs.
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Pulmonary ventilation (breathing)
Gas exchange between alveoli and
blood.
Gas transport (O2 transport and CO2
transport) by blood
Gas exchange between blood and
tissues
Cellular or tissue respiration