Question

How do we classify different groups of tissues as organ or glands ? And what features can we use to define a gland ?

Answer 1

Tissueis a cellular organizational level betweencellsand a completeorgan. A tissue is an ensemble of similar cells and theirextracellular matrixfrom the same origin that together carry out a specific function. There are four maintypes of tissue: muscle, epithelial, connective and nervous. Each is made of specialized cells that are grouped together according to structure and function. Muscle is found throughout the body and even includes organs such as the heart. Our outer layer of skin is epithelialtissue.Organs are then formed by the functional grouping together of multiple tissues.example, the heart, lungs, liver, eyes, and stomach Aglandis a group of cellsin an animal's body that synthesizes substances (such ashormones) for release into thebloodstream(endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Examples of glands are:

• salivary glands that secrete saliva into the mouth.
• bile-producing glands of the liver.
• prostate gland.
• the portion of the pancreas that secretes pancreatic fluid into the duodenum. ...
• gastric glands.
• sweat glands.