Final answer:
Exocrine glands use three secretion modes: merocrine, apocrine, and holocrine. Merocrine involves exocytosis without damaging the cell; apocrine releases part of the cell with the product; and holocrine secretion involves the destruction of the entire cell to release its content.
Step-by-step explanation:
The Three Modes of Secretion in Exocrine Glands
The exocrine glands have three different modes of secretion: merocrine, apocrine, and holocrine secretion. These mechanisms are used to release substances through a duct to the epithelial surface.
- Merocrine Secretion: This is the most common type. Vesicles inside the cell transport the secretions to the cell's surface and release them via exocytosis without harming the cell.
- Apocrine Secretion: In this type, part of the cellular apical surface pinches off, releasing the secretory product along with some cytoplasm from the cell.
- Holocrine Secretion: The entire cell disintegrates to release its secretion, meaning the cell itself becomes a part of the secretion.
Examples of merocrine secretion include the glands that produce saliva and the eccrine sweat glands. Apocrine glands are associated with hair follicles in regions such as the armpits and groin. Holocrine secretion can be seen in the sebaceous glands associated with hair follicles.