Give an account of glandular epithelium.

Cuboidal cells (or) columnar cells specialised for secretions form glandular epithelium.

1. Based on number of cells present, they are of 2 types:
   i) Unicellular glands - Eg : Goblet cells of gut that secrete mucus
   ii) Multicellular glands - Eg : Salivary glands
2. Based on mode of secretions, they are 2 types:
   a) Exocrine glands/Duct glands : Secrete mucus, saliva, milk etc. out onto body surfaces. 
   Eg: Salivary glands
   b) Endocrine glands/Ductless glands : Secrete hormones into blood. Eg : Thyroid gland
3. Based on release of secretion, they are three types as shown below: