Are glands in human made up of muscles?
No they are not made of muscles. Glands are modified epithelial tissues. Glands are basically of two types Endocrine and Exocrine glands.


Endocrine gland   


It is a gland that lacks a duct system. The secretions are directly
   poured into the bloodstream. They secrete hormones through exocytosis mostly.


Exocrine gland 


It is a gland with a duct system. The secretions(sweat, sebum,saliva
   etc) are transported onto a surface of the body (e.g skin or lumen of GI tract) by
   ducts.Exocrine glands may be controlled by muscles at the duct level.

There are three types of exocrine glands based on the process of secretion of chemical substance at a cellular level$-$


Apocrine gland


It is a gland in which the apical portion of the secretory cells are distintegrated to release the chemical. e.g- Apocrine sweat gland


Holocrine gland


It is a gland in which the secretory cells are completely disintegrated to release the chemical.e.g.- Sebaceous gland


Merocrine gland


It is a gland in which the secretory cells remain intact and the chemical is 
released through exocytosis.e.g.- salivary gland



Reference: 


Wikipedia
ncbi