We explain what histology is and the topics that this discipline studies. Also, plant and animal histology and importance.
What is Histology?
Histology is a discipline which is part of the biology and examines the tissues of the organisms through a microscope to know your structure and its functions. It is also called "microscopic anatomy" or "micro anatomy." The word histology comes from the Greek, histo which means "tissue" and logos, which means "knowledge".
Marcello Malpighi, Italian anatomist and biologist, is considered the founder of histology for having been the first to examine cells alive through a microscope in the early 17th century. Malpighi was the one who discovered the existence of small units within tissues, called cells.
What does histology study?
Histology studies the microscopic structure of tissues, that is, complex groupings of cells organized to fulfill a specific function. The human being, for example, originates from the fusion of two cells: an egg and a sperm. Both cells, in turn, then divide repeatedly to form new cells that make up the different tissues, organs, and systems of the human body. Histological examinations provide insight into how the various components of the body are organized, interrelated, and function. organism.
Histological examinations provide important contributions to:
- Histopathology. It is the part of histology that examines tissue samples taken from a diseased organism to learn more about the possible causes of the disease and provide insight diagnosis more precise.
- Forensic investigations and autopsies. The analysis of biological tissues, through techniques They can shed light on the causes of unexpected deaths and provide scientific evidence available to the public. Justice.
- The arqueology. By examining the cells and biological tissues found in recovered remains of ancient societies, you can get information about its history.
- The education. The basic techniques of histology are taught in laboratory workshops to introduce students to the concept of microstructures of different organisms.
General biology recognizes the existence of two groups of organisms: vascular plants (from kingdom plantae) and animals (from animal Kingdom). Based on this distinction, histology is subdivided into plant histology and animal histology to categorize the different tissues.
Plant histology
Plant histology is the specific study of plant tissues that are classified into two types:
- Meristematic or embryonic tissues. They are made up of small cells that have a great capacity to multiply.
- Adult tissues. Are those permanent or of duration in the plant and they are made up of cells larger than embryonic ones. These, in turn, can be:
- Parenchymal tissues. They are made up of cells that are responsible for nutrition and the accumulation of reserves.
- Protective or surface fabrics. They are made up of cells that cover the plant and isolate it from the external environment.
- Supportive tissues or collenchyma. They are composed of cells with thick walls and an elongated shape that give the plant rigidity.
- Conductive or vascular tissues. They are made up of cylindrical cells that join together and form tubes or ducts, through which nutrients circulate.
- Secretory and excretory tissues. They are made up of cells that secrete plant substances, such as pine resin.
Animal histology
Animal histology studies the organic tissues of animals that, unlike the plant kingdom, have cells that form very diverse organisms in terms of their shape and function. Animal tissues are classified into four types:
- Epithelial tissues. They are made up of several layers of cells joined together that form a cellular membrane that covers all surfaces of the body (such as the epidermis, digestive and respiratory tracts) and internal cavities (such as arteries, veins and capillaries).
- Connective or conjunctive tissues. They contain cells of varying shape together with a viscous material that separates them, called “intercellular substance”, which allows other tissues to join to provide support and integration, for example, adipose, cartilaginous, bone and blood tissue .
- Muscle tissues. They are made up of elongated cells called "muscle fibers", which contain myofibrils capable of contracting and giving elasticity to the muscles. Depending on the shape and type of contraction, muscles are classified as skeletal, cardiac, and smooth.
- Nervous tissues. They are made up of cells called "neurons”That establish a complex connection system and have the ability to regenerate extremely slowly. They function as receptors of stimuli (neurons sensitive) to which they respond with nerve impulses (motor neurons) that propagate successively to other neurons (association neurons).
Importance of histology
The study of histology allows us to know the structure and function of the organs through microscopic examination of the cells that make them up. The results of histological studies are key for medicine and for biology, both to know the properties of the organism under normal conditions and to examine the presence of pathologies, their evolution and their possible diagnosis.