Content- Definitions of histology History Scopes Histological techniques in brief

1. Mammalian Histology
Chapter: 1
Introduction and scope of histology
By: Bithika Baidya
Content:
• Definitions of histology
• History
• Scopes
• Histological Techniques in brief

2. ❖ Definitions of Histology
‘Histology’ is a Greek word ; ‘histos’ means tissue and ‘logia’ means ‘knowledge’
Thus histology is knowledge of tissue
✓ “The branch of biology which deals with the study of microscopic structure of tissues and
organ with their function”
✓ “Histology is a branch of anatomy which concerns itself with the structural organization of
tissue”
✓ “Histology known as microscopic anatomy or microanatomy is a branch of biology which
studies microscopic anatomy of biological tissue.”
✓ “Histology known as study of form of structure seen under microscope (light, electron,
infrared), also called as microscopic anatomy”

3. ❖ History
✓ French anatomist Xavier Bichat is the ‘father of modern histology’ introduced the concept of tissue in
anatomy in 1801
✓ The term ‘Histology’ was coined to denote ‘study of tissue’ by Karl Mayer in 1819
✓ 1906 Nobel Prize in Physiology or Medicine was awarded to histologist Camillo Golgi and Santiago Ramon
Cajal. (Worked on nerve cells leading to the discovery of structure and function of nervous system)
Xavier Bichat Karl Mayer Camillo Golgi Santiago Cajal

4. ❖ Scope
1. Education: a) Tissue as building block
✓ Histology can help students gain better understanding of cell behaviour making cell biology more
understandable.
✓ Likewise, tissues are building block of everything in the body understanding histology will help students to
predict the co-relation between structure, function and behaviour of an organ
b) Understanding development and evolution
✓ Some organism have no organ and are made entirely of tissues. Similarity with the histology helps students
gain insight into the development of organ and organ system. While evaluating this the student can gain
knowledge on how organ system developed and changed in the course of life.
2. Research:
✓ Many diseases occur at tissue level (Eg: Cancer), for medical professionals research in histology will help
to develop important facts and conclusion in order to treat the diseases.
✓ One can understand the effect of different chemical on tissue via histological research (Toxicity and
carcinogenic)
✓ Research can help you to understand why some treatment work more effectively than other and why
certain lifestyle choice can harm your body over time

5. ❖ Scope:
3. Medical Field:
✓ Histology is used to diagnose disease in human, animals and plants and to analyse the effect and
treatment
✓ A pathologist can identify abnormal cell and tissue conditions and diseases, including cancer and parasitic
infection so that the doctor can give treatment plan.
✓ Histology is used during autopsies and forensic investigation to help understand unexplained death. In
some cases, cause of death is evident from microscopic examination of tissue.
✓ Many medical technology companies and pharmaceutical companies require to test their products need
trained histologist.
4. Other: The variety of fields using histology is ever expanding and has a strong laboratory component.
✓ Histologist working in laboratories include biomedical scientists, medical technicians, histology
technicians (HT), histological technologist (HTL).
✓ Histochemistry: branch of science concerned with the identification and distribution of chemical
constituent in a tissue by means of staining and microscopy.
✓ Archaeologist use histology to study biological material recovered from archaeological sites (Bones and
teeth are most likely to provide data)
✓ Palaeontologists may recover useful material from organism preserved in amber or frozen.

6. ❖ Histological techniques in brief:
✓ Histological technique explains the methodology to obtain animal or plant tissue section, processing,
staining and observing the obtained section under a microscope.
✓ The various steps included in it are obtaining samples, fixation, processing embedding, sectioning and
staining.

7. ❖ Histological techniques in brief:
Structural details of animal tissues can be studied by using the following methods
• Examination of Living cells without chemical treatment
a) Fresh, uncoloured: drop of blood
b) Transparent chamber method: growth of blood vessels and nerves can be directly seen under microscope
c) Tissue culture and organ culture
• Examination of Living cells after chemical treatment
a) Supra vital staining: living cell or tissue can be stained without killing the cell and observed under microscope.
Eg: Janus Green is a supra vital stain used to stain mitochondria
b) Vital staining: dyes without killing the cell. Dye administered via food or injection
• Examination of killed cell:
a) Maceration: tissue is treated with strong and dilute acid and the intercellular substance is removed. Due to the treatment
individual cells, tissue can be isolated.
b) Corrosion: tissue is treated with strong alkali solution so that soft parts dissolves and calcareous part can be maintained
c) Immunohistochemistry: antigen and antibody reaction is carried out in presence of a fluorescent dye.
d) Radio Autography: Radioactive precursor are applied to the tissue for determination of its location in the cell. They are
labelled substance (14C, 3H, 128I , 132I)
e) Historadiography: When X-rays are used for photographing tissue to identify elements, called
Historadiography.
f) Histochemical methods: certain substance in tissue and cells have special affinity for certain chemical substance
or dye.

8. Question
• Define Histology
• Who is the father of modern histology?
• Write short note on scopes in histology.
• Define:- Maceration, Corrosion, Immunohistochemistry, Radio Autography, Historadiography, Histochemical methods
THANK YOU