Glands| Ductless |Human physiology

                  Glands|Ductless| |Autocrine|

      Keywords:|Receptor|Signal| Intracrine|Autocrine|Paracrine|Juxtacrine|Endocrine|

What is a gland? 

A gland is a group of cells in the body. They synthesize and release substances that perform a specific function in the body.

Enteroendocrine cells are spread throughout the intestinal tract and not clustered together. Therefore, the cells are not in groups. However, if taken together, they are one of the largest endocrine systems in the body. They are about 1% of the epithelial cells of GIT. They are specialized for secretion.

Types of ductless glands in the human body:

1. Intracrine

2. Autocrine

3 Paracrine.

4. Juxtacrine

5. Endocrine

Study of a characteristic unique feature of different types of ductless glands:

Intracrine: is a hormone that acts inside a cell, i.e., the cell stimulates itself by producing a factor that works within the cell –the hormone is not secreted outside the cell. Instead, the hormone is secreted in the cell and acts on the receptors present inside the cell in which it is produced. For example, steroid hormones act through intracellular (primarily nuclear) receptors and thus may be considered to be intracrine. Several peptide/protein hormones or isoforms also operate inside the cell through different mechanisms.

In contrast, hormones act by binding to their receptors present on the cell surface. The biological effects produced by intracellular actions are Intracrine effects, and it is intracrinology. Some peptide/protein hormones are also Intracrines, e.g., Fibroblast growth factor2, and Parathyroid hormone-related protein.

Autocrine: They act on their own surface. Cells of autocrine glands secrete the autocrine factors that bind to receptors on their own character, causing changes in the cell. For example, the cytokine interleukin -1 in monocytes is an autocrine agent. When interleukin-1 is produced in response to external stimuli, it can bind to cell-surface receptors on the same cell that created it.

Paracrine: They act on nearby cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance- and exert local action. Cells of paracrine glands secrete the paracrine factors into the immediate extracellular environment. However, the exact length that the paracrine factors can travel is uncertain. Target cells are nearby cells not attached by gap junction.

Juxtacrine:  Juxtacrine glands act on nearby cells like paracrine glands, but the main difference in Juxtacrine secretions requires physical contact with the partition on which they are performing. Cells of Juxtacrine glands secrete the Juxtacrine factors, and its target cells have physical contact.

 Endocrine: Endocrine glands secret substances that enter the bloodstream by their basal lamina and circulate through the bloodstream. These glands secrete hormones that play essential roles in maintaining homeostasis. Endocrine glands are part of the endocrine system of the body. Examples of endocrine glands are the pineal gland, pituitary gland, thyroid gland, two adrenal glands, etc.

Cells of endocrine glands secrete the endocrine factors or hormones that travel a long distance via the circulatory system to reach the target cells.

The word endocrine is derived from the Greek words endon  =inside within and secrete.

Hashtags: Receptor#Signal# Intracrine#Autocrine#Paracrine#Juxtacrine#Endocrine#

 

 

                      

Internal link:   https://totalphysiology20.blogspot.com/2021/02/glands-we 

                        https://totalphysiology20.blogspot.com/2021/02/salivary glands-we  

External link:   https://en.m.wikipedia.og>wiki

                         https:// www.britannica.com>science

                          https://www.siencedirect.com>pil

Please follow on Twitter,Facebook.

 Pl. like, comment and subscribe.