Gland

As gland (Latin glandula ) is in the anatomy called an organ that forms a particular substance and this either as secretion secretes externally ( excretory gland, exocrine gland ) or as a hormone directly into the bloodstream emits ( incretory gland, endocrine gland ).

Excretory glands

Excretory glands are also called exocrine glands. They have a duct through which the secretion reaches the surface of the skin or a mucous membrane. The origin of the ductal explained by the fact that the glands are displaced in its embryonic origins of the surface of the epithelium in the depth and differentiate into organs with their typical specialized epithelial cells, but remain with the original epithelial surface in conjunction.

It differs according to the type of the excretory glandular secretion and on the type of dispensing secretion.

Distinction based on the nature of the secretion

Serous glands produce a thin liquid, enzyme-containing secretion:

• Parotid gland ( parotid )
• The pancreas ( pancreatic ), satisfies both excretory, and endocrine functions
• Lacrimal gland ( lacrimal gland )

Mucous glands produce a viscous, mucous secretion:

• Gland in the cervix
• Brunner's glands of the duodenum
• Glands in the throat and on the tongue root
• Cowper's gland to the urethra of male individuals

Mixed glands produce according to requirements serous or mucous secretions:

• Goblet cells of the respiratory tract
• Mandibular and sublingual salivary gland

Distinction according to the secretory

In Wehner / Gehring ( zoology, 24th edition ) can be distinguished, the skin glands of vertebrates by following Sekretionstypen:

• Merokrin, formerly ekkrin: discharge small, barely visible by light microscopy secretion droplets (aqueous secretions ) by exocytosis. The cell remains the same. These include the sweat glands.
• Apokrin: discharge of large drops of secretion (concentrated proteinaceous secretions ), with a portion of the cell is cut off in the secretion and release tampered with. These include the scent glands and the mammary glands of the female breast.
• Holocrine: conversion of the entire cell contents to secretion. The cells perish, the cell body becomes the secretion. Continuous regeneration of the cells is necessary. These include the sebaceous glands.

Incretory glands

Incretory glands are also known as endocrine glands, or ductless glands. You have no duct and release their active ingredients ( hormones) directly from the blood. The totality of these glands is called the endocrine system.