Question

Ciliated epithelium is found in which one of the following organs?
A. Stomach
B. Respiratory tract
C. Small intestine
D. Brain
E. None of these

Answer 1

Hint: Epithelial tissue or epithelium is a layer of cells that are present on body surfaces and as a lining of organs and cavities. As a specialization, epithelial tissue at certain locations have cilia on them and are known as ciliated epithelium. The cilia help in a unidirectional movement of suspended particles or fluid.

Complete answer:
Option (a) is incorrect. The stomach is a muscular organ that helps to digest food chemically and mechanically. The lining of the stomach is covered by columnar epithelial cells. The epithelium here consists of tubular gastric glands. The epithelial cells of the stomach are known to secrete a thick mucous that protects the cells from acid secreted by the stomach.
Option (b) is correct. The epithelial cells of the respiratory tract are of ciliated columnar type and have goblet cells. This type of epithelium protects the respiratory passageway by providing a physical barrier to foreign particles. The ciliated cells are also known to regulate the movement of mucus up the tract for expulsion.
Option (c) is incorrect. The small intestine is composed of simple columnar epithelial cells. The primary function of these cells is absorption of nutritive substances into the body. These cells also prevent the entry of pathogens and thus protect the body.
Option (d) is incorrect. The brain is composed of neuronal cells and glial cells. The neuronal cells are involved in transmission of signals through synapses. Glial cells are non-neuronal cells that are not involved with transmission of signals. Their primary function is to support the neurons, maintain homeostasis and form the myelin.

Hence, the correct answer is option (B).

Note: Epithelial cells are found on body surfaces. They protect the body from invading pathogens. Some epithelial cells have free cilia on their surfaces and are called ciliated epithelium. These cells are generally present in organs where there is movement of particles or matter. For example, ciliated epithelium of the respiratory tract helps to move mucus, that in the female reproductive tract helps in the movement of ovum towards the uterus and away from the ovary.