Name: exocrine glands and their secretion types
Uploaded: 2023-06-23T15:38:46.000Z
Duration: 1 min 8 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.14

SC.912.L.14.29

Exocrine Glands: Methods of Secretion

Exocrine glands are classified as merocrine, apocrine, or holocrine based on how they secrete their glandular products.
Cells of merocrine glands, such as salivary gland cells, release their products in secretory vesicles via exocytosis while the cells remain intact and prepare for additional secretions.
Apocrine gland cells, such as those in the axillary sweat glands, accumulate their secretory products right below the surface. When the apex of the cell pinches off, the secretory granules are released together with a small amount of cytoplasm.
The cells then regrow and repair their apices before further product release.
In holocrine glands, such as sebaceous glands of the skin, superficial epithelial cells become packed with secretory vesicles. When the cell bursts, the product is released.
The continuous division of underlying layers of stem cells replaces the ruptured cells.

exocrine glands: methods of secretion

Exocrine glands are those that release their secretions through ducts. Based on their mode of secretion, they can be classified into merocrine, apocrine, and holocrine.
Merocrine Secretion
Merocrine secretion is the most common type of exocrine secretion. The secretions are enclosed in vesicles and moved to the cell&#39;s apical surface, where the contents are released by exocytosis. For example, mucous, a watery secretion rich in the glycoprotein mucin, is a merocrine secretion. The eccrine glands that produce and secrete sweat are another example of merocrine secretions.
Apocrine Secretion
In apocrine secretion, the accumulated secretory contents pinch out along with the apical portion of the cell and are released to the outside of the cell. For example, fatty secretions produced by the sweat glands of the axillary and genital areas are apocrine secretions. Both merocrine and apocrine glands continue to produce and secrete their contents with little damage caused to the cell because the nucleus and Golgi regions remain intact after secretion, enabling the cell membrane to reform after secretion.
Some glands use a combination of these two secretory methods to release their products. For example, the lactating mammary glands release lipid droplets into milk by apocrine secretion, while the protein casein is released into milk by merocrine secretion.
Holocrine Secretion
In contrast, in holocrine secretion, the cell accumulates its secretory products and releases them only when it bursts, thus leading to the rupturing&#160;and destruction of the entire cell. Cells from the surrounding tissue then differentiate into new gland cells to replace cells lost during secretion. The sebaceous glands that produce the oils on the skin and hair are holocrine glands.
This text is partially adapted from <a href="https://openstax.org/books/anatomy-and-physiology/pages/4-2-epithelial-tissue">Openstax, Anatomy and Physiology 2e, Section 4.2: Epithelial Tissue</a><a href="https://openstax.org/books/anatomy-and-physiology/pages/4-2-epithelial-tissue">s</a>

Exocrine glands are those that release their secretions through ducts. Based on their mode of secretion, they can be classified into merocrine, apocrine, ...

Education

JoVE Core

Anatomy and Physiology

Unit 1

Tissues of the Human Body

KEY TERMS AND CONCEPTS

exocrine glands and their secretion types

Exocrine glands release their products through ducts. Their secretion pattern helps group them into three types: merocrine, apocrine, and holocrine. These types differ in how the gland cell releases its material.

Merocrine secretion is the most common type. In this process, the secretory product is packed into vesicles and moved to the apical surface of the cell. The contents are then released by exocytosis. Mucous, a watery secretion rich in the glycoprotein mucin, is one example. The eccrine glands that make sweat are another example.

Apocrine secretion works differently. The secretory material pinches off with the apical part of the cell and is released outside the cell. Fatty secretions from the sweat glands in the axillary and genital areas are examples of apocrine secretion. Merocrine and apocrine glands can keep working with little damage because the nucleus and Golgi regions stay intact, and the cell membrane can reform after secretion. Some glands use both methods. In lactating mammary glands, lipid droplets enter milk by apocrine secretion, while casein is released by merocrine secretion.

Holocrine secretion is the third type. Here, the cell stores its secretory product until it bursts. This releases the product and destroys the entire cell. New gland cells then form from nearby tissue to replace the lost cells. Sebaceous glands, which produce the oils on the skin and hair, are holocrine glands.

Exocrine Glands and Their Secretion Types

exocrine-glands-and-their-secretion-types

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classification of epithelial tissues: simple epithelium

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Simple Epithelium: Types and Cell Shapes

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classification of epithelial tissues: stratified epithelium

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Stratified Epithelium Types and Locations

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classification of epithelial tissues: glandular epithelium

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Glandular Epithelium: Secretory Cell Types

Glandular epithelium is epithelial tissue made of cells that are modified to make and release chemical substances. In high school biology, it is often studied by how many secretory cells it contains and how it sends out its products. Unicellular glands contain single secretory cells scattered within an epithelial layer. Multicellular glands have a hollow tubular duct connected to a group of secretory cells that sit in deeper pockets. These multicellular glands begin during early development...

exocrine glands: unicellular and multicellular glands

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Exocrine Gland Types and Duct Patterns

Exocrine glands are classified by the number of cells and by duct structure. Unicellular glands are single scattered cells, such as goblet cells in the mucous membranes of the small and large intestines. Multicellular exocrine glands form as secretory sheets, like the internal lining of the abdomen or chest, and they release their secretions directly into the lumen of these organs. Some multicellular glands also have deep secretory units and a hollow duct. The secretory units make the product,...

Exocrine glands release their products through ducts. Their secretion pattern helps group them into three types: merocrine, apocrine, and holocrine. These types differ in how the gland cell releases its material. Merocrine secretion is the most common type. In this process, the secretory product is packed into vesicles and moved to the apical surface of the cell. The contents are then released by exocytosis. Mucous, a watery secretion rich in the glycoprotein mucin, is one example. The eccrine...

exocrine glands: types of secretions

Exocrine Gland Secretions and Examples

Exocrine glands produce glandular products and release them outside the body or into a duct. These glands are grouped as serous, mucous, or mixed based on the kind of secretion they make. The three categories help show how gland structure relates to function. Serous glands make watery secretions that are rich in digestive enzymes and proteins. Their cells usually have centrally located nuclei and eosinophilic secretory granules in the cytoplasm, which means the granules stain strongly with...

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Connective Tissue Types and Functions

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Embryonic Support Tissues in Development

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Loose and Dense Connective Tissue Types

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Extracellular Matrix in Connective Tissue

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loose connective tissue

Loose Connective Tissue Types and Functions

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key terms and concepts

Learn how exocrine glands use merocrine, apocrine, and holocrine secretion, with examples such as sweat glands, mammary glands, and sebaceous glands.

Exocrine Glands and Their Secretion Types | JoVE K12

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Exocrine Glands and Their Secretion Types

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