8/10/2019 Theme1(Aurthor O.mazuru)
1/25
The State University of Medicine and
Pharmacy N. Testemitanu
CEO of departament of Histology, Cytology and Embryology
Lilian Saptefrati
Vice CEO of departament of Histology, Cytology and Embryology
Tatiana Globa
CYTOLOGY. CELL THEORY.
HISTOLOGICAL TECHNIQUES,CELLULAR FORMES.
8/10/2019 Theme1(Aurthor O.mazuru)
2/25
8/10/2019 Theme1(Aurthor O.mazuru)
3/25
Cytology is the study of the cells.
Cells are the structural units of all livingorganisms. In the human body there are
about 200 types of the cells, but they differ
from one another by: shape, size and
function.
8/10/2019 Theme1(Aurthor O.mazuru)
4/25
Histology - is the study of the tissues of the
body and how these tissues are arranged
to constitute organs.
Histology involves all aspects of tissue
biology, with the focus on how cells'
structure and arrangement optimize
functions specific to each organ.
8/10/2019 Theme1(Aurthor O.mazuru)
5/25
8/10/2019 Theme1(Aurthor O.mazuru)
6/25
Compartments of the cell:
Cell membrane (cytolemma),
cytoplasm,
nucleus.
8/10/2019 Theme1(Aurthor O.mazuru)
7/25
Cell theory( modern interpretation):
The cell is the fundamental unit of structure and
function in living things.
All cells come from pre-existing cells by division.
Energy flow occurs within cells.
Cells contain hereditary information (DNA) which
is passed from to cell during cell division.
All cells are the same in chemical composition. The activity of an organism depends on the totel
activity of independent cells.
8/10/2019 Theme1(Aurthor O.mazuru)
8/25
Basic methods of research in
morphology.
Light microscopy,
Fluorescence microscopy,
Phase-Contrast microscopy,
Confocal microscopy,
Polarizing microscopy,
Electron microscopy ,
Scanning Electron microscopy,
Autoradiography .
8/10/2019 Theme1(Aurthor O.mazuru)
9/25
What could we do with
collected material?
- sections,
- smears,
- prints and
- membranes.
8/10/2019 Theme1(Aurthor O.mazuru)
10/25
8/10/2019 Theme1(Aurthor O.mazuru)
11/25
Technics of histological specimens
preparation
collection and fixation
dehydration and clearing
embedding
mounting and staining the section
8/10/2019 Theme1(Aurthor O.mazuru)
12/25
Fixation
to preserve the structure and molecularcomposition , pieces of organs should be
promptly treated by fixatives (formalin).
What for?
for cross-link proteins,
for innactivated the enzymes of autolyzis,
increase the affinity of protoplasm for future
stains.
8/10/2019 Theme1(Aurthor O.mazuru)
13/25
The process of paraffin embedding, or
tissue impregnation ( for easyer cutting oftissues), is ordinarily preceded by two
main steps: dehydration and clearing.
The water is first extracted from thefragments to be embedded by bathing
them successively in a graded series of
mixtures of ethanol and water, usuallyfrom 70% to 100% ethanol (dehydration).
8/10/2019 Theme1(Aurthor O.mazuru)
14/25
ClearingUses for remove alcohol. The clearing
solutions are: xylol, toluol, chloroform which aremiscible in both alcohol and parafin.
Result the tissues infiltrated with one of thisorganic solvents become transparent.
8/10/2019 Theme1(Aurthor O.mazuru)
15/25
Result of embedding into paraffin
8/10/2019 Theme1(Aurthor O.mazuru)
16/25
Sectioning by microtome.
8/10/2019 Theme1(Aurthor O.mazuru)
17/25
Staining and mounting
To be studied microscopically sections
must typically be stained or dyed because
most tissues are colorless. Staining permit
distinctions to be made between tissuecomponents.
8/10/2019 Theme1(Aurthor O.mazuru)
18/25
Basic dyes
Tissuecomponents that
stain more readily
with basic dyesare termed
basophilic
(nuclearchromatin,
nucleolus).
8/10/2019 Theme1(Aurthor O.mazuru)
19/25
Acid dyesTissue
components thatstain more
readily with acid
dyes arenamed
acidophilic or
oxiphilic( cytoplasm,
collagen fibres,
etc.)
8/10/2019 Theme1(Aurthor O.mazuru)
20/25
Metachromasia
When some basic dyeschange their colordepending on theirconcentration.
Ex.: toluidine blue isblue in diluted solutionbut purple inconcentrated solution.Staining of thecartilage matrix it willchange its color.
8/10/2019 Theme1(Aurthor O.mazuru)
21/25
8/10/2019 Theme1(Aurthor O.mazuru)
22/25
Electron microscopy.
8/10/2019 Theme1(Aurthor O.mazuru)
23/25
Blood smear (of frog)
nucleus
cytoplasm
cell
membrane
8/10/2019 Theme1(Aurthor O.mazuru)
24/25
Cuboidal-shaped cells from renal
tubules
nucleus
cytoplasm
cell membrane
tubule cavity
8/10/2019 Theme1(Aurthor O.mazuru)
25/25
Neurons from the ventral
horns of the spinal cord
1. nucleolus2. nucleus
3. cytoplasmatic
processes