The following table shows different epithelial tissues in animals and their location in different parts. Identify the correct option.

	Epithelial Tissue		Location
A.		i)	Respiratory tract
B.		ii)	Skin
C.		iii)	Lining of blood vessels
D.		iv)	Ducts of salivary glands

The correct answer is A - iii, B - iv, C - i, D - ii.

Key-points

• Based on the descriptions given, the epithelial tissues can be matched to their corresponding locations in the body as follows:
  • Pseudostratified Columnar Epithelium  - Respiratory Tract
  • Stratified Squamous Epithelium - Skin
  • Simple Squamous Epithelium - Lining of Blood Vessels
  • Simple Cuboidal Epithelium - Ducts of Salivary Glands

Additional Information

• Pseudostratified Columnar Epithelium (Respiratory Tract):
  • This is a single-layered tissue with nuclei at different levels, making it appear stratified.
  • It lines the trachea and bronchi, where it secretes and moves mucus using its cilia.
• Stratified Squamous Epithelium (Skin):
  • This multi-layered tissue is found in areas exposed to friction like the skin.
  • The cells on the surface are flat, while those underneath can be cuboidal or columnar.
  • This tissue protects underlying tissues from injury, infection, and dehydration.
• Simple Squamous Epithelium (Lining of Blood Vessels):
  • This is a single layer of flat cells that allows rapid diffusion or transport of substances.
  • Found in the lining of blood vessels, it reduces friction for the flowing blood.
• Simple Cuboidal Epithelium (Ducts of Salivary Glands):
  • Consisting of a single layer of cube-shaped cells, this tissue is involved in secretion, absorption, and excretion.
  • Found in glands and their ducts like salivary glands, it helps in transporting saliva to the mouth.