What is the Difference Between Apocrine and Eccrine Sweat Glands

The main difference between apocrine and eccrine sweat glands is that the secretions of the apocrine sweat glands are viscid whereas the secretions of eccrine sweat glands are watery. Furthermore, apocrine sweat glands are always connected to hair follicles while eccrine sweat glands are not connected to hair follicles.

Apocrine and eccrine sweat glands are two types of sweat glands found in the skin.

Key Areas Covered

1. What are Apocrine Sweat Glands
     – Definition, Distribution, Composition of Secretions, Role
2. What are Eccrine Sweat Glands
     – Definition, Distribution, Composition of Secretions, Role
3. What are the Similarities Between Apocrine and Eccrine Sweat Glands
     – Outline of Common Features
4. What is the Difference Between Apocrine and Eccrine Sweat Glands
     – Comparison of Key Differences

Key Terms

Apocrine Sweat Glands, Body Odor, Distribution, Eccrine Sweat Glands, Thermoregulation

What are Apocrine Sweat Glands

Apocrine sweat glands are one of the two main types of sweat glands found in the skin. They occur in specific areas of the skin like armpits, scrotum, anus, and labia majora. One of the main characteristic features of apocrine sweat glands is the opening of the sweat gland into a hair follicle. Also, the secretions of the apocrine sweat glands are viscid. These secretions are made up of proteins and fatty acids. Therefore, they are thicker and milky.

Figure 1: Apocrine Sweat Gland

The secretions of apocrine glands are responsible for body smells. This smell is due to the bacterial degradation of these secretions and the various chemicals produced in the degradation process are responsible for the body odor. Significantly, apocrine sweat glands become active at puberty.

What are Eccrine Sweat Glands

Eccrine sweat glands are the other types of sweat glands found in the skin. This type of sweat glands occurs all over the skin. They are more concentrated in the forehead, neck, and back areas. But, eccrine sweat glands do not secrete into a hair follicle.

Figure 2: Eccrine Sweat Glands

The secretions of these type of sweat glands are made up of water and NaCl. Evaporation of this type of sweat uses the body heat. Therefore, it helps to cool down the body. Thus, eccrine sweat glands play a key role in thermoregulation. Also, the amount of sweat secreted is increased with the physical exercises. The eccrine sweat glands are responsible for the moisture produced in the palm and sole area when a person is emotionally stressed.

Similarities Between Apocrine and Eccrine Sweat Glands

• Apocrine and eccrine sweat glands are two types of sweat glands found in the skin.
• They are also called sudoriferous glands.
• Also, both are exocrine glands made up of small, tubular structures.
• Furthermore, they secrete different forms of secretions in the skin.

Difference Between Apocrine and Eccrine Sweat Glands

Definition

Apocrine sweat glands refer to a gland, especially a sweat gland that secretes a viscous fluid into a hair follicle whereas eccrine sweat glands refer to a type of simple sweat gland that is found in almost all regions of the skin. Thus, this explains the difference between apocrine and eccrine sweat glands.

Distribution

Furthermore, apocrine sweat glands occur in the armpits and perianal areas in humans while eccrine sweat glands occur all over the skin.

Diameter of Individual Secretory Tubule

Moreover, the diameter of the apocrine sweat gland is 80-100 μm while the diameter of eccrine sweat gland is 30-40 μm.

Diameter of the Secretory Coil

In addition, the diameter of the secretory coil of the apocrine gland is 800 μm while the diameter of the secretory coil of the eccrine gland is 500-700 μm.

Secretory Unit

Besides, a major difference between apocrine and eccrine sweat glands is that the secretory unit of the apocrine glands is made up of simple columnar epithelium, while the secretory unit of the eccrine glands is made up of mixed clear cells and dark cells.

Ductal Epithelium

Also, the ductal epithelium of the apocrine glands is made up of lobule layer of cuboidal cells while the ductal epithelium of eccrine glands is made up of several layers of cuboidal cells.

Duct Opens to

Another difference between apocrine and eccrine sweat glands is that the duct of the apocrine glands opens to a hair follicle while the duct of the eccrine glands opens to the skin surface.

Texture of the Secretion

We can also find a difference between apocrine and eccrine sweat glands in their respective secretions. While the secretion of apocrine glands is viscid, secretion of eccrine glands is watery.

Composition of the Secretion

Furthermore, the secretion of the apocrine sweat glands consists of proteins and fatty acids while the secretion of the eccrine sweat glands consists of water and sodium chloride. This is another important difference between apocrine and eccrine sweat glands.

Function

Functionally too we can identify a difference between apocrine and eccrine sweat glands. The secretions of apocrine sweat glands are mainly responsible for body odor while the secretions of the eccrine sweat glands are responsible for the cooling of the body.

Conclusion

Apocrine sweat glands are a special type of sweat glands in the skin, which secrete a viscid secretion into a hair follicle. They are mainly found in the armpits and the genital area. The products of the bacterial degradation of this type of sweat are responsible for the body odor. On the other hand, eccrine sweat glands are the second type of sweat glands found all over the skin, which secretes a watery secretion. The evaporation of this type of sweat is responsible for the cooling of the body. The main difference between apocrine and eccrine sweat glands is the distribution, types of secretion, and the role.

Reference:

1. “Accessory Structures of the Skin.” Boundless Anatomy and Physiology, Lumen Learning, Available Here

Image Courtesy:

1. “Blausen 0438 HairFollicleAnatomy 02” By BruceBlaus. Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia  
2. “501 Structure of the skin” By OpenStax College – Anatomy & Physiology, Connexions Web site. Available here, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia