1. بسم الله الرحمن الرحيم

2. By Prof. Dr. Nahed Zohdy Professor of Histology & Cell Biology
The cell By
Prof. Dr. Nahed Zohdy
Professor of Histology & Cell Biology

3. About this Lecture Cytoplasm: Structure Organelles Ribosomes ER
Golgi apparatus
Lysosomes
Mitochondria

4. Haematoxylin and Eosin (H&E)
Haematoxylin is a basic violet stain.
Eosin is an acidic pink stain.
Acidophilic structure= A structure that has affinity to stain with acidic dyes = basic in nature………So it stains pink with eosin
Basophilic structure= A structure that has affinity to stain with basic dyes = acidic in nature……… So it stains violet with haematoxylin

5. The cytoplasm Composed of: 1- Cytosol:
jelly like fluid matrix, its primary component is water
2- Organelles
3- Inclusion
4- Cytoskeleton
cytoplasm
Nucleus

6. Organelles Little organs: - Living structures Types:
- Metabolicaly active
- Perform certain functions
- Permenant
- Present in all cell types
Types:
- Memberanous organelles
Non-membranous organelles

7. Ribosomes
- Non-membranous organelles - Chemical nature: nucleoproteins consist of proteins conjugated with ribosomal RNA (rRNA)
Structure:
LM:
By H&E stain: can not be seen
if large in number they impart Cytoplasmic basophilia.

8. EM: 2 subunits: Electron dense granules Small subunit (RNA+30 P)
large subunit (2RNA+40 P)

9. Types of ribosomes Free
Attached
Solitary
Polysomes

10. Polysomes
- Clusters of ribosomes connected by mRNA thread & producing identical proteins
mRNA
ribosomes
Free protein in cytoplasm

11. Attachment of ribosmes to the rER

12. EM of attached ribosomes

13. Function of ribosomes Ribosomes are the sites of protein synthesis:
Solitary: reserve
Polysomes: proteins used by the cell
Attached: proteins for secretion outside the cell

14. Endoplasmic reticulum
- Membranous organelle
- Network of interconnecting tubules and cisternae

15. Endoplasmic reticulum
Rough
(rER)
Smooth
(sER)

16. rER
sER
Cyto. basophalia LM
Cyto. acidophilia

17. rER sER EM -Interconnected branching tubules -Interconnected parallel
-Lacks ribosomes-
-No connection with nucl.
-Interconnected parallel
cisternae
-Has attached ribosomes
-Connected to nuclear m.

18. rER sER EM Interconnected cisternae Interconnected tubules
Has attached ribosomes
Interconnected tubules
Lacks ribosomes

19. rER sER Function Participates in protein synthesis.
1- Lipid synthesis (fatty acids ,cholestrol & steroid hormones)
2- Detoxification of toxic substance
3- Muscle contraction
(control calcium ions -sarcoplasmic reticulum)
4- Glycogen synthesis

20. Role of rER in protein synthesis
1- receiving of polypeptide chains in ER lumen
2- storage
3- protein trasport

21. Golgi apparatus Structure: LM: -Membranous organelle
-H&E stain: not apparent
- Special stain: silver stain

22. Golgi apparatus in epididymis (Silver stain)
Brown anastomosing network of threads at the secretory border of the cells

23. EM structure of Golgi apparatus
3 components:
- macrovesicles
- flattened membranous saccules. (4-10)
- microvesicles
Flattened membranous cisternae:
Convex surface: immature face
Concave surface: Secretory face = mature face

24. Fate of protein transported by rER

25. Fate of protein transported by rER
Primary lysosomes

26. Functions of Golgi apparatus
1- Chemical modification of proteins
2- Formation of primary lysosomes
3- Secretion of cell products
4- Renewal of the cell membrane

27. Cytoplasmic Organelles that participate in the process of protein synthesis
1- Ribosomes (factories)
2- Rough endoplasmic reticulum (storage & transport)
3- Golgi apparatus (chemical modification & secretion)

28. Lysosomes Definition: (Digestive system of the cell)
- Membrane bound organelles containing hydrolytic enzymes
(Digestive system of the cell)

29. Lysosomes LM Structure: Histochemical methods staining their enzymes
- Membrane bound organelles containing hydrolytic enzymes
Structure: LM
Histochemical methods staining their enzymes

30. EM 2 types 1ry lysosome 2ry lysosome
small, regular vesicle , contains homogenous dense content
2ry lysosome
Large, irregular vesicle, contains heterogenous dense and light contents

31. Function of lysosomes
- The digestive system of the cell (contain hydrolytic enzymes that could digest the food vacuole's contents & destroy old cell organelles)

32. Formation of the 2 types of lysosomes

33. Forms of secondary lysosomes
1-pinocytotic vesicles = multivesicular body
2- phagosomes =residual bodies
3- autophagic vacuole = residual bodies
5- Lipofuscin pigment

34. Mitochondria Structure: LM: -Membranous organelles
Mitos= thread
chondros= granule
-Membranous organelles
Structure:
LM:
-H&E stain: not apparent
- Special stain: silver stain

35. LM picture of mitochondria (special stain: silver stain)
mitochondria appear as dark brown granules

36. EM of the Mitochondria Double membranes: -Outer smooth
-Inner folded forming cristae
Double spaces:
-intermembranous space
- intercristal space (matrix space)
intermembranous space

37. - cristae to increase surface area
Inner membrane:
- cristae to increase surface area
- contains protein enzymes for respiratory chain
- contains ATP
synthetase for ATP synthesis
Matrix:
- oxidative enzymes
- mitochondril DNA so mitochondria can replicate themselves

38. Function of a mitochondrion
-Energy production & storage (ATP synthesis)
-Concerned with cell respiration (sites for Kreb’s and fatty acid cycles)

39. LM: can not be seen EM: - small, rounded - similar to 1ry lysosomes
Peroxisomes
- Contain 40 oxidative enzymes (urate oxidase)
LM: can not be seen EM: - small, rounded - similar to 1ry lysosomes

40. Functions of peroxisomes:
1- Generate energy but can not store it (NO ATP formation)
2- Maintenance of body temperature (The energy is released as heat).
3- Cell protection : catalase enzyme
breaks down H2O2.

41. Thank you