INTRODUCTION 
TO GENERAL MICROANATOMY AND EMBRYOLOGY

The body contains at least 200 distinct cell types. These cells contain essentially the same internal structures yet they vary enormously in shape and function. The different types of cells are not randomly distributed throughout the body; rather they occur in organized layers, a level of organization referred to as tissue.
The variety in shape reflects the many different roles that cells fulfill in your body. The human body starts as a single cell at fertilization. As this fertilized egg divides, it gives rise to trillions of cells, each built from the same blueprint, but organizing into tissues and becoming irreversibly committed to a developmental pathway.


HISTOLOGIC METHODS.

LIGHT MICROSCOPY method - Allows to see only cell NUCLEUS and only CYTOPLASM, because magnification of light microscope is not sufficient for revealing of ORGANELLES and
CHROMOSOMES.          
 
 If objective lenses have magnification x40 and ocular lenses - x7,

TOTAL magnification of LIGHT microscope is: 40 x 7= 280 times.


Steps for slide manufacturing in method of light microscopy:
a)  Fixation of specimen in FORMALIN solution.
b)  Dehydration – is removal of water from specimen. Put it in ETHYL ALCOHOL.
c)  Embedding – is infiltration of specimen by melted. PARAFFIN.
d)  Sectioning – is cutting of specimen by histologic knife with aim to get SECTIONs with thickness 7 micrometers. Device for this – is MICROTOME.
e) Staining of section by histologic Dyes.

Dyes are classified on 2 types: 

1) COMMON dyes

2) SPECIAL dies

Common dyes
reveal only pink cytoplasm and blue nucleus, without chemical identification of cellular content. Common dyes are classified on:

a) BASIC dyes.  It is HEMATOXYLIN. It stains NUCLEUS in BLUE colour.

b) ACIDIC dyes. It is EOSIN. It stains CYTOPLASM in PINK colour.

Special dyes reveal only ONE CHEMICAL of cellular content.
It may be: ORSEIN for revealing of ELASTIC fibres;
SUDAN BLACK for staining of LIPID droplets into BLACK colour.

ELECTRON MICROSCOPY method (=EM). Allows to see: ORGANELLES, CHROMOSOMES, CHROMATIN, because electron microscope gives magnification x5.000 times up to x30.000 times.

There are 2 types of EM method:
A) TRANSMISSION EM (TEM method). It gives PLANE picture of organelles and chromatin;
B) SCANNING EM (SEM method). It gives 3-D image of cell.

HISTORADIOAUTOGRAPHY method. It allows to evaluate RATE of DNA duplication. If in microslide number of SILVER GRAINS on phone of nucleus is big, it signifies about AST rate of DNA duplication.

IMMUNOCYTOCHEMISTRY method. It allows to see proteins-RECEPTORS on the surface of PLASMA MEMBRANE. If after injection of LABELED MONOCLONAL ANTIBODIES into rat, plasma membrane is stained into pink colour (into colour of LABEL), it means :proteins-RECEPTORS present.

PHASE CONTRAST MICROSCOPY method. It allows to see

ALIVE and NON-stained cells, to evaluate RATE of SPERMATOZOA movement.