Theme1(Aurthor O.mazuru)

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.


2/25


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.


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.


5/25


6/25

Compartments of the cell:

Cell membrane (cytolemma),

cytoplasm,

nucleus.


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.


8/25

Basic methods of research in

morphology.

Light microscopy,

Fluorescence microscopy,

Phase-Contrast microscopy,

Confocal microscopy,

Polarizing microscopy,

Electron microscopy ,

Scanning Electron microscopy,

Autoradiography .


9/25

What could we do with

collected material?

- sections,

- smears,

- prints and

- membranes.


10/25


11/25

Technics of histological specimens

preparation

collection and fixation

dehydration and clearing

embedding

mounting and staining the section


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.


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).


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.


15/25

Result of embedding into paraffin


16/25

Sectioning by microtome.


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.


18/25

Basic dyes

Tissuecomponents that

stain more readily

with basic dyesare termed

basophilic

(nuclearchromatin,

nucleolus).


19/25

Acid dyesTissue

components thatstain more

readily with acid

dyes arenamed

acidophilic or

oxiphilic( cytoplasm,

collagen fibres,

etc.)


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.


21/25


22/25

Electron microscopy.


23/25

Blood smear (of frog)

nucleus

cytoplasm

cell

membrane


24/25

Cuboidal-shaped cells from renal

tubules

nucleus

cytoplasm

cell membrane

tubule cavity


25/25

Neurons from the ventral

horns of the spinal cord

1. nucleolus2. nucleus

3. cytoplasmatic

processes

Documents

Theme1(Aurthor O.mazuru)