1. DR /Noha Elsayed 2014--2015 Anatomy &Physiology CLS 221 Cells and Tissues

2. objectives Name the three main parts of a human cell. Describe the structure and function of the plasma membrane. Describe the structure and function of the nucleus. Describe the structures and roles of the endoplasmic reticulum and the Golgi apparatus in the cytoplasm. Describe the structures of lysosomes and the role of these organelles in the breakdown of molecules. Describe the structure of mitochondria and their role in producing ATP. Describe the structures of centrioles, cilia, and flagella and their roles in cellular movement. Describe the structures and function of the cytoskeleton. Describe how substances move across the plasma membrane, and distinguish between passive and active transport. 2

3. CELL (the basic structural and functional unit of the living things)  Carry out all chemical activities needed to sustain life  Cells are the building blocks of all living things TISSUES Tissues are groups of cells that are similar in structure and function. Dr. Dalia Mohsen3

4. Anatomy of the Cell :-  All the cells are not same  All cells share general structures  Cells are organized into three Main regions 1.Nucleus 2.Cytoplasm 3.Plasma membrane 4

5. 1. The Nucleus 1. The Nucleus :-  Control center of the cell  Contains genetic material DNA (deoxyribonucleic acid)  Three regions  Nuclear membrane  Nucleolus  Chromatin 5

6. Nuclear Membrane :-  Barrier of nucleus  Consists of a double phospholipid membrane  Contain nuclear pores that allow for exchange of material with the rest of the cell Dr. Dalia Mohsen6

7. Nucleoli :- Nucleus contains one or more nucleoli Sites of ribosome production Ribosomes then migrate to the cytoplasm through nuclear pores Dr. Dalia Mohsen7

8. Chromatin :- Composed of DNA and protein Scattered throughout the nucleus Chromatin condenses to form chromosomes when the cell divides 8

9. 2. Plasma Membrane:- (outer most layer that surrounds the cytoplasm of the cell) Barrier for cell contents Double phospholipid layer –Hydrophilic heads –Hydrophobic tails Other materials in plasma membrane –Protein –Cholesterol –Glycoproteins 9

10. Plasma Membrane:- Dr. Dalia Mohsen10

11. Plasma Membrane Specializations:- 1. Microvilli Finger-like projections that increase surface area for absorption. Dr. Dalia Mohsen11

12. Continue:- Plasma Membrane Specializations :- 2. Membrane junctions (site where two cells attached to each other)  Tight junctions  Desmosomes  Gap junctions Dr. Dalia Mohsen12

13. 3. Cytoplasm:- Material outside the nucleus and inside the plasma membrane Cytosol Fluid that suspends other elements Organelles Metabolic machinery of the cell Inclusions Non-functioning units 13

14. Cytoplasmic Organelles:-Cytoplasmic Organelles:- 14

15. Cytoplasmic Organelles 1- Ribosomes Made of protein and RNA Sites of protein synthesis Free in the cytoplasm Attached to rough endoplasmic reticulum Dr. Dalia Mohsen15

16. 2-Endoplasmic reticulum (ER) Fluid-filled tubules for carrying substances Two types of ER Rough Endoplasmic Reticulum:- Studded with ribosomes Site where building materials of cellular membrane are formed Smooth Endoplasmic Reticulum:- Functions in cholesterol synthesis and breakdown, fat metabolism, and detoxification of drugs Dr. Dalia Mohsen16

17. 3-Golgi apparatus Modifies and packages proteins Produces different types of packages Secretory vesicles Cell membrane components Lysosomes 17

18. Cytoplasmic Organelles:-Cytoplasmic Organelles:- Dr. Dalia Mohsen18

19. 4- Lysosomes :- Contain enzymes that digest waste materials within the cell. 5- Peroxisomes:- –Membranous sacs of oxidase enzymes –Detoxify harmful substances 19

20. 4-Mitochondria  “Powerhouses” of the cell  Change shape continuously  Carry out reactions where oxygen is used to break down food  Provides ATP ( adenosine triphosphate) for cellular energy 20

21. 5-Cytoskeleton  Three different types  Microfilaments  Intermediate filaments  Microtubules 21

22. 6-Centrioles :-  Rod-shaped bodies made of microtubules  Direct formation of mitotic spindle during cell division 22

23. Membrane Transport Membrane Transport – movement of substance into and out of the cell Transport is by two basic methods :- –Passive transport No energy is required –Active transport The cell must provide metabolic energy Dr. Dalia Mohsen23

24. Solutions and Transport :- Solution :- homogeneous mixture of two or more components Solvent – dissolving medium Solutes – components in smaller quantities within a solution Intracellular fluid :-nucleoplasm and cytosol Interstitial fluid:-fluid on the exterior of the cell 24

25. Selective Permeability :- The plasma membrane allows some materials to pass while excluding others This permeability includes movement into and out of the cell 25

26. Passive Transport Processes:-  Diffusion Particles tend to distribute themselves evenly within a solution Movement is from high concentration to low concentration 26

27. Types of diffusion: 1-Simple diffusion Unassisted process Solutes are lipid-soluble materials or small enough to pass through membrane pores 27

28. 2-Osmosis – simple diffusion of water Highly polar water easily crosses the plasma membrane )Movement of a solvent from an area of low concentration to one of high concentration( 3-Facilitated diffusion Substances require a protein carrier for passive transport 28

29. –Diffusion through the Plasma Membrane Dr. Dalia Mohsen29