What is histology and how to use it to define and introduce it.

Histology is defined as the scientific study of the microstructure (microanatomy) of cells and tissues. The word "histology" comes from the Greek word "histos", which means organization or pillar, and "logia" means research. The word "histology" first appeared in a book written by German anatomist and physiologist Karl Meyer in 18 19, and its roots can be traced back to the microscopic study of biological structure by Italian doctor Marcello Malpighi in17th century.

How does histology work

Histology course focuses on the preparation of histological slides, which depends on the previous mastery of anatomy and physiology. Optics and electron microscopes are usually taught separately.

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Three-dimensional human brain tissue cultured by stem cells

The five steps of histological slide preparation are as follows:

fixed

process

insert

slice up

Dye

Cells and tissues must be fixed to prevent decay and degeneration. Processing is needed to prevent the organization from changing excessively when embedding. Embedding involves placing the sample in a supporting material (such as paraffin or plastic) so that the small sample can be sliced and suitable for microscopic examination. Slice with a special blade called slicer or ultraslicer. Place the section on a microscope slide and stain it. There are a variety of dyeing schemes to choose from to enhance the visibility of specific types of structures.

The most common dyeing is the combination of hematoxylin and eosin (H&; E staining). Hematoxylin dyed the nucleus blue, while eosin dyed the cytoplasm pink. The images of H& electronic slides are usually pink and blue. Toluidine blue stained the nucleus and cytoplasm blue, but the mast cells were purple. Wright's staining dyed red blood cells blue/purple, while changing white blood cells and platelets into other colors.

Hematoxylin and eosin will produce permanent staining, so slides made from this combination can be stored for future inspection. Some other histological stains are temporary, so microphotography is needed to save the data. Most trichromatic dyeing is differential dyeing, and a mixture will produce multiple colors. For example, Malloy's trichromatic dyes make cytoplasm red, nucleus and muscle red, red blood cells and keratin orange, cartilage blue and bone dark blue.

Organizational model

Two kinds of tissues are plant tissues and animal tissues.

To avoid confusion, plant histology is usually called "plant anatomy". The main types of plant tissues are:

fibrovascular tissue

Dermal tissue

meristem

Ground organization

In humans and other animals, all tissues can be divided into one of the following four categories:

nerve tissue

musculature

epithelium

connective tissue

These main subclasses include epithelium, endothelium, mesothelium, mesenchymal, germ cells and stem cells.

Histology can also be used to study the structure of microorganisms, fungi and algae.

Organizational specialty

People who prepare tissue sections, sections, stains and images are called histologists. Histologists work in the laboratory and have highly refined skills to determine the best way to cut samples, how to dye sections to make important structures visible, and how to image slides with a microscope. The experimenters in the histology laboratory include biomedical scientists, medical technicians, histology technicians (HT) and histology technicians (HTL).

Sections and images made by histologists are examined by pathologists. Pathologists are good at identifying abnormal cells and tissues. Pathologists can identify many symptoms and diseases, including cancer and parasitic infections, so other doctors, veterinarians and botanists can make treatment plans or determine whether abnormalities will lead to death.

Histopathologists are experts in studying diseased tissues. Histopathology usually requires a medical degree or a doctorate. Many scientists in this subject have double degrees.

The use of histology

Histology is very important in science education, applied science and medicine.

Histology is taught to biologists, medical students and veterinary students because it can help them understand and identify different types of tissues. In turn, histology bridges the gap between anatomy and physiology by showing the changes in tissues at the cellular level.

Archaeologists use histology to study biological materials recovered from archaeological sites. Bones and teeth are most likely to provide data. Paleontologists can recover useful materials from creatures preserved in amber or frozen in permafrost.

Histology is used to diagnose human, animal and plant diseases and analyze the therapeutic effect.

Histology is used to help understand unexplained deaths in autopsy and forensic investigation. In some cases, the cause of death can be found by microscopic examination. In other cases, microdissection may reveal clues about the postmortem environment.