Cell Biology Lecture Notes - Badr University in Assiut

CELL BIOLOGY Prof.Dalia A. El-gamal Head of Basic Medical science Departmeant Badr University in Assiut  Cytology = Cell biology ◦ Is the science which deals with the structure, function and molecular construction of the cell with the use of microscopes and...

CELL BIOLOGY Prof.Dalia A. El-gamal Head of Basic Medical science Departmeant Badr University in Assiut  Cytology = Cell biology ◦ Is the science which deals with the structure, function and molecular construction of the cell with the use of microscopes and various techniques.  METHODS OF STUDYING CELLS There are two main procedures for studying cells: 1- Examination of living cells as (Tissue culture 2- Examination of fixed tissues 27/03/1445  1- Examination of living cells (Tissue culture) Cell &Tissue culture *Definition: is the maintenance and study of live cells and tissues outside the body in culture (in vitro). *Advantages: 1. Cell culture allows the direct observation of living cells. 2. Experiments which are technically impossible to perform in the body (in vivo) can be accomplished in culture (in vitro). 27/03/1445  *Uses: 1. In research on cell structure and function. 2. For genetic or chromosomal analyses. 27/03/1445  2- Examination of fixed tissues Paraffin sections. Frozen Sections. Plastic sections. 27/03/1445 Preparation of Paraffin sections include the following steps: 1-obtaining the tissue must be fresh and few mm in thickness to achieve good Fixation. 2-Fixation means preservation of the tissue to state identical to that in life An example of fixatives is a. 10%formalin or formal saline b. Bouin (picric acid/formalin/acetic acid) c. Osmic acid d. 4% Glutaraldehyde+ 10%formalin. 27/03/1445  3-Dehydration means gradual extraction of water from the tissue by increasing concentrations of ethanol alcohol. 4-Clearing in a chemical agent as xylol organic solvent to replace the alcohol and make tissue more clear. 5-Impregnation: Infiltration of the tissue with melted paraffin in an oven (56 ©) to provide internal support of the tissue. 27/03/1445 6-Embedding: fixed tissues are infiltrated and embedded in Paraffin( a material with a firm consistency to form sections). Embedding facilitates the straight, thin cutting of the specimen. 27/03/1445 7-Cutting: After the paraffin has cooled, the block of paraffin is cut. The specimen is cut into thin slices. 27/03/1445 8-Attaching section to slides (Mounting): Each section is mounted on a clean glass slide covered by a thin layer of egg albumin or glycerin, then dried on hot plate. 27/03/1445 9-Staining: organic solvent is used to remove all of the paraffin from the tissue. The specimen is then rehydrated by putting in solutions that simultaneously contain less and less alcohol and more and more water. Different stains are used e.g. Hematoxylin and eosin or Sudan black. 27/03/1445  https://youtu.be/nUjK4n3_1C8?si=wbx5Pirr3-hTkCtr ◦ 27/03/1445 Thank you 27/03/1445