In animal histology, the term parenchyma is used to refer to the tissue responsible for the function of the organ to which it belongs. For example, glandular epithelium, one of the main types of epithelial tissue, would be the parenchyma of the glands, as the glands are specialized in secretion and this secretion is carried out by this part of the gland.
Parenchyma is also used in plant histology to refer to one of three essential plant tissue types: parenchyma, collenchyma, and sclerenchyma. Unlike its use in animal histology, which does not refer to a specific tissue type or function, but to a part of an organ, plant parenchyma is considered a type of tissue with specific characteristics and functions.
Parenchyma of animal organs
The parenchyma, parenchymal tissue or parenchymal tissue in animals is the functional part or tissue of organs as opposed to stroma which are the structural and supporting tissues. Neither of the terms, neither stroma nor parenchyma, refers to a specific type of tissue, but to its functional characteristics.
However, the stroma in humans and other mammals almost always coincides with a specialized connective tissue type. In the case of parenchyma, there are many other types of functional tissue. I would like parenchymal tissues depending on the organ: glandular tissue, nerve tissue, muscle tissue, bone tissue, etc.
Example: lung parenchyma: lung parenchyma is the tissue involved in gas exchange. It is located in the alveoli and in the bronchioles or terminal bronchial branches.
Example: liver parenchyma: The liver parenchyma is formed by hepatocytes and other specialized liver cells, such as Ito cells or hepatic stellate cells, and is differentiated from hepatic vascular tissue and bile duct tissue.
Example: Brain parenchyma: Brain parenchyma is made up of nervous tissue that mainly consists of two types of cells, neurons and glial cells.
In plants, three groups of tissues are distinguished: fundamental tissues, vascular tissues (phloem and xylem) and protective tissues (dermis and epidermis). Within the fundamental tissues, three subtypes are distinguished:Parenchyma Collenchyma Sclerenchyma
Of the three fundamental tissue types, parenchyma is the most common and abundant. It presents cells with thinner walls than the cells of the rest of the plant tissues and constitutes the largest proportion in the soft parts of the plant, including leaves, flowers and fruits.
The entire plant parenchyma forms a continuous tissue that performs different functions depending on its location and content, distinguishing two types of plant parenchyma:Chlorenchyma: (not to be confused with collenchyma) is the parenchyma specialized in photosynthesis. reserve parenchyma: it has a storage function and is very abundant in underground parts, for example in tubers, and in internal parts. It is very abundant in some types of plants, for example in cacti.