What does SI mean? Definitions for SI Here are all the possible meanings and translations of the word SI.
The sebaceous glands are microscopic exocrine glands in the skin that secrete an oily or waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals.ebaceous glands secrete the oily, waxy substance called sebum (Latin: fat, tallow) that is made of triglycerides, wax esters, squalene, and metabolites of fat-producing cells. Sebum waterproofs and lubricates the skin and hair of mammals.
What are endocrine glands? Endocrine glands are glands of the endocrine system that secrete  their products, hormones, directly into the blood rather than  through a duct. The endocrine system containâ¦s glands that release  certain hormones for growth/body functions/body reactions. It  consists of eight major parts:   pituitary gland  pineal gland  thyroid gland  parathyroid gland  adrenal gland  pancreas  ovary  testis   .