Question

Describe the alveolar structure and the respiratory membrane

Please be detailed.

Answer 1

Respiratory membrane is also called air-blood barrier.

Simple squamous epithelium of alveoli attached to a thin, elastic basement membrane which borders the endothelial membrane of capillaries, together (alveoli and capillary membranes) forms the respiratory membrane. It is approximately 0.5mm in thick. Respiratory membrane allows gases to cross the membrane by simple diffusion. It allows oxygen picked up by blood and CO2 to be released into air of the alveoli. Respiratory membrane can be thickened by certain factors like fluid in the lungs, fibrosis or scarring of the lungs.

Alveolus Blood Capillary out

Alveoli: It is a tiny ballon shaped structure and the smallest passage way in the respiratory system. Alveoli is only one cell thick, allowing easy passage of oxygen and carbon dioxide between alveoli and capillaries. These are present at the end of the respiratory tree arranged in clusters throughout the lungs. Alveoli are made up of two types of cells

Type 1 pneumocytes which are responsible for gases exchange and type 2 pneumocytes that are responsible for repairing damage to alveolar lining and secrete surfactant.

Alveoli