Epithelium, which is composed of closely arranged epithelial cells and a small amount of extracellular matrix, has the functions of protection and secretion. There are often abundant spiritual terminals in epithelial tissues, most of which have no blood vessels. Epithelial tissues often differentiate into some special structures on the free, lateral and basal surfaces. Classification of epithelial tissue: coated epithelium, glandular epithelium (two types in the narrow sense), sensory epithelium and myoepithelium.
(1) Materials to be prepared: sterilized toothpicks (one blunt and one pointed), glass slides, cover slides, straws, dropping bottles, filter paper, dye solution (0.9% sodium chloride solution), diluted iodine solution
(2) Operation process:
1. clean slide: wipe the slide and cover glass with clean gauze.
2. dripping water: put the slide on the test bench, and drop a drop of normal saline in the center of the slide with a dropper. The purpose is to maintain the normal morphology of oral epithelial cells in vitro.
3. materials: gently scrape the thick end of the sterilized toothpick on the side wall of the mouth after rinsing.
4. apply Put the chippy end of the toothpick into the normal saline in the center of the slide and smear it for a few times.
5. cover slide: clamp the cover slide with tweezers to make one side contact the liquid drop on the slide, and then slowly cover the liquid drop at 45 °, cover the cover slide, and make a temporary slide. Use absorbent paper to absorb excess water, so as to avoid bubbles under the cover glass and affect the observation.
6. staining: add 1 ~ 2 drops of iodine solution to one side of the cover glass. The drop of iodine solution is to stain the cells for easy observation.
Adsorption: on the other side of the cover glass, absorb it with absorbent paper to make the dye infiltrate all of the cover glass If the excess dye is not sucked dry in time, the observation will be affected.
Observation: with a low power microscope, irregular flat cells can be observed, which are human oral epithelial cells. The cell membrane and nucleus with deep staining and the cytoplasm with shallow staining were observed.
(3) Precautions:
a. Sampling position
The anterior part of the top wall of the mouth is hard palate, the posterior part is soft palate, and the bilateral walls are buccal. Each wall of the oral cavity is covered with mucous membrane.
In this experiment, the buccal parts on both sides of the oral cavity were the best. Because more oral epithelial cells can be taken from this part, the toothpick should be attached to the inner wall of the mouth and scraped gently to avoid the toothpick tip damaging the inner wall of the mouth.
b. Dye concentration
The cytoplasm, nucleus and cell membrane of oral epithelial cells can be clearly displayed only when the appropriate dye concentration is selected.
