بسم الله الرحمن الرحيم

1. بسم الله الرحمن الرحيم

2. The cell By Prof. Dr. NahedZohdy 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 - 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 consistof proteins conjugated with ribosomal RNA (rRNA) • Structure: • LM: • By H&E stain: can not be seen • if large in number they impart Cytoplasmicbasophilia.

8. EM: Electron dense granules 2 subunits: 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 LM Cyto. basophalia Cyto. acidophilia

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

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

19. sER rER 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 -Membranous organelle Structure: LM: -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: - Membrane bound organelles containing hydrolytic enzymes (Digestive system of the cell)

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

30. EM 2 types 1ry 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 1ry lysosome + 1-pinocytotic vesicles = multivesicular body 2- phagosomes =residual bodies 3- autophagic vacuole = residual bodies 5- Lipofuscin pigment

34. Mitochondria chondros= granule Mitos=thread -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. 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. Peroxisomes LM:can not be seenEM:- small, rounded- similar to 1ry lysosomes - Contain 40 oxidative enzymes (urateoxidase)

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