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 Karl Meyer, a German anatomist and physiologist, in 18 19, and its roots can be traced back to the microscopic study of biological structure by Italian doctor Marcello Malpighi in 17 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 preparing histological slides are:

fixed

process

insert

slice up

Dye

Cells and tissues must be fixed to prevent decay and degradation. In order to prevent excessive changes in the organization during embedding, it needs to be processed. 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 improve the visibility of specific types of structures.

The most common staining 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 staining dyed red blood cells blue/purple, and changed white blood cells and platelets into other colors.

Hematoxylin and eosin will produce permanent staining, so slides made with this combination can be stored for later inspection. Some other histological stains are temporary, so microphotography is needed to save the data. Most trichromatic dyeing is differential dyeing, and single mixing produces 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 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.

Histology major

People who prepare tissue sections, cuts, 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).

Slides and images made by histologists are examined by doctors called pathologists. Pathologists specialize in 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 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 what happens to tissues at the cellular level.

Archaeologists use histology to study biological materials found in archaeological sites. Bones and teeth are most likely to provide data. Paleontologists can recover useful materials from organisms 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 can reveal clues about the environment after death.