Question

The alveolar epithelium in the lung is?
A. Non- ciliated columnar
B. Non- ciliated squamous
C. Ciliated columnar
D. Ciliated squamous

Answer 1

Hint: Alveoli are tiny air sacs in our lungs that take up the oxygen we breathe in.
A pulmonary alveolus is a hollow cup-shaped cavity found in the lung parenchyma where gas exchange takes place.

Complete answer:
-Lung alveoli are found in the acini at the beginning of the respiratory zone.
-The alveoli consist of an epithelial layer of simple squamous epithelium and an extracellular matrix surrounded by capillaries.
-Simple columnar epithelium is divided into two categories: ciliated and nonciliated (glandular).
-The non ciliated part of the simple columnar epithelium helps in increasing the surface area for the exchange of gases.

So, the correct option is B

Additional information:
-Alveoli are located sparsely in the respiratory bronchioles, line the walls of the alveolar ducts, and are more numerous in the blind-ended alveolar sacs.
The acini are the basic units of respiration, with gas exchange taking place in all the alveoli present.
-The alveolar membrane is the gas exchange surface, surrounded by a network of capillaries.
-Across the membrane oxygen is diffused into the capillaries and carbon dioxide is released from the capillaries into the alveoli to be breathed out.
-The epithelial lining is part of the alveolar membrane, also known as the respiratory membrane, that allows the exchange of gases.
-The membrane has several layers – a layer of lining fluid that contains surfactant, the epithelial layer and its basement membrane.
- A thin interstitial space between the epithelial lining and the capillary membrane.
- A capillary basement membrane that often fuses with the alveolar basement membrane, and the capillary endothelial membrane.

Note:
The cells in the respiratory epithelium are of four main types:
 a) ciliated cells
 b) goblet cells
 c) club cells
 d) airway basal cells