• Merocrine (aka, eccrine),
• Apocrine, and
• Holocrine modes of secretion as discussed in Junqueira.

Note that the terms refer to means by which the cell discharges its secretory products, not to morphology or to cellular staining properties based on the rER content.

What is another process that basically means the same thing as merocrine/eccrine secretion?

Which mode of secretion occurs most commonly among glands in humans?

The plasma membrane is next.