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Introduction. Essential Cytology
1.
Department ofHistology, Cytology and
Embryology
Lecture 1. Introduction.
Essential Cytology
2.
Histology studies the organization of thetissues and organs of the body.
Cytology studies the structure and functions
of the cell.
Embryology researches embryonic
development (formation) of the body
3. Cytology
Note:1. The cell is the smallest structural
and functional unit of the body
2. Cells
3. Tissues form organs and systems
form
tissues.
4. Note:
Types of cells in human body5.
Cells produce matrix6. Cells produce matrix
Methods of investigation7. Methods of investigation
Microscopy – basicmethod
Light microscope:
Histological slide:
8. Microscopy – basic method
Electron microscopy9. Electron microscopy
researchesUltrastructure of cells
(organelles) and
organisation of
intercellular matrix
10. Electron microscopy researches
Light and electron microscopy are 2 mane methods in histology11. Light and electron microscopy - are 2 mane methods in histology
Levels of biological systemsBiomolecules
Membranes
Organelles
CELL
12. Levels of biological systems
Phospholipids structure :Phosphate group (hydrophilic
heads)
Glycerol
Fatty acids (hydrophobic tails)
13. Phospholipids structure :
Membrane contents:A. Phospholipids:
(1 – hydrophilic
head, 2 –
hydrophobic
tails)
B. (3 ) – proteins
C. (4 ) –
carbohydrates
(only outer cell
membrane)
14. Membrane contents:
Proteinsmay constitute close to 50% of
membrane content
15. Lipids may be:
Proteinsfunction:
123456-
channels,
pumps,
receptors,
enzymes,
integrative,
structural
16. Proteins may constitute close to 50% of membrane content
CarbohydratesPresent in the outer cell membrane
Form Receptors
17. Proteins function:
Cell consists of:- Outer cell membrane,
- Cytoplasm and
- Nucleus
18. Carbohydrates
If cells contact, outer cell membraneforms
junctions
G
1
2
19.
Tight junctionprevents the movement
of molecules into the
intercellular spaces
present between
epithelial cells
20. Membranes form:
21. Cell consists of:
Gap junctionchannels
between cells
22.
DesmosomesProvide cell
attachment
23. Types of Cell junction
Inside the cell …Cytoplasm consists of:
Matrix (hialoplasm, cytozol)
Organelles
Inclusions
24. Tight junction
Inclusionsgranules with
secretions,
pigment
granules, lipid
and glycogen
droplets
25.
Organelles:(classification by structure)
Membranous
Non-membranous
26. Gap junction
Organelles:(classification by function)
General
(present in every cell,
perform general
function)
Ex.: Mitochondrion
Special
(in specialised cell,
perform special
function)
= Myofibril
27. Desmosomes -
Rough endoplasmic reticulumMembranes form a
network of sac-like
structures called
cisternae .
Ribosomes lie on the
outer surface.
Function - synthesis
of proteins
28. Inside the cell …
29. Inclusions -
Smooth endoplasmic reticulum, SER30. Organelles: (classification by structure)
SER structure: membranes form tubuleswithout ribosomes.
Function:
1. synthesizis of lipids.
2. metabolism of carbohydrates
3. drug detoxification (in liver cells).
4 storage of Ca-ions (only in muscle cell)
31. Organelles: (classification by function)
Golgi complex (or apparatus)= a pack of sacs.
32. Rough endoplasmic reticulum
Golgi complex …… is connected with
endoplasmic reticulum
33.
Golgi apparatusfunctions:
1. formation of
compound
molecules –
glycoproteins,
lipoproteins.
2. production of
lysosomes and
secretory vesicles.
34. Smooth endoplasmic reticulum, SER
MitochondrionStructure :
Contains outer and
inner membranes
--Folds of inner
membrane – cristae
--- Inside lie matryx
35.
MitochondrionProduce ATP
molecules (energy) by
Krebs cycle
36. Golgi complex (or apparatus)
LysosomeLysosomes are round vesicles that
contain enzymes
These enzymes break down waste
materials and cellular debris and digest
the materials within phagosomes.
37. Golgi complex …
Non-membranous organelles:Microfilaments
Microtubules
Centrioles (Cell Center)
Ribosomes
38. Golgi apparatus functions:
Note:Microfilaments, Microtubules
form “Skeleton” of the cell
39. Mitochondrion
Cell centerConsists of 2 centrioles
Centriole = 9 x 3 = 27
microtubules;
Function - formation
of mitotic spindle
40. Mitochondrion
Nucleusconsists of:
Nucleolemma =
nuclear envelope
Nucleoplasm
Nucleolus
Chromatin
41. Lysosome
Nuclear envelope- Consists of two
membranes:
outer and inner
42. Non-membranous organelles:
In the nuclear envelopethere are gaps,
called nuclear
pores, provide
transport from
nucleus into
cytoplasm
43.
NucleolusNucleolus is the
site of active
synthesis of
ribosomal RNA and
formation of
ribosomes.
44. Cell center
Chromatinis the combination of DNA and proteins
that make up the contents of the nucleus
of a cell.
45. Nucleus consists of:
Chromatin =DNA in non-dividing cells.
2 types:
1. heterochromatin
(non-active) - very
tightly packed fibrils .
2.euchromatin active – less
condensed chromatin
fibrils loops
46. Nuclear envelope
Euchromatin predominates in metabolically activenuclei,
Heterochromatin predominates in metabolically
inactive nuclei
47. In the nuclear envelope
Chromosome- is an organized structure of DNA
and protein found in dividing cells.
48.
Cell cycle49.
Thelife of a somatic cell is a
cyclic process
It
It
is called
cell cycle
consists of two periods:
interphase and mitosis.
50. Chromatin
InterphaseInterphase is a period
between two divisions
of the cell.
Consists of 3 phases G1 , S , G2
51. Chromatin = DNA in non-dividing cells.
In G1 phase:cell grows,
performs its
routine functions.
52.
S- phase(S- synthesis)
DNA molecules are duplicated
NOTE: At the beginning of this phase the
chromosome number is 2N
and at the end each chromosome consists
of two DNA molecules or two chromatids,
the chromosome number is 4N.
53. Chromosome - is an organized structure of DNA and protein found in dividing cells.
G2 phaseIn this phase synthesis of proteins, which
are required for cell division, takes place.
After phase G2 mitosis always begins
54.
Mitosisis the process of somatic cells
division.
Mitosis consists of four phase:
prophase,
metaphase,
anaphase,
telophase.
55.
ProphaseChromosomes
become
recognisable.
the nuclear
membrane breaks
down and the
nucleoli disappear
56. Interphase
Two centriolesseparate and move to
opposite poles of the
cell.
microtubules pass
from one centriole to
other and form a
spindle of division.
57. In G1 phase:
Metaphase- chromosomes
move to a position
midway between
the two centrioles
(the equator of the
cell) and form the
equatorial plate
58. S- phase (S- synthesis)
Anaphase- the chromatids
separate and move
to opposite poles
of the cell
At the end of
anaphase
chromatids are
called
chromosomes.
59. G2 phase
Telophasetwo daughter nuclei
are formed
chromosomes become
indistinct.
Nucleoli reappear.