بسم الله الرحمن الرحيم

1. بسم الله الرحمن الرحيم Introduction and cell physiology By Ahmed Osman Noury

2. What is human physiology? • Is the scientific study of function in living organism from sub cellular to organ and system level. • And the study of how this systems perform their function and integrate with each other to maintain homeostasis

4. Organ Systems In Review • Circulatory • Digestive • Endocrine • Immune • Integumentary • Musculoskeletal • Nervous • Reproductive • Urinary The integration between systems of the body

5. Plan of Human Body

6. Homeostasis • The maintenance of internal environment constancy. • The internal environment is made up of the Extra Cellular Fluid or ECF Internal environment = fluid surrounding cells

7. Homeostasis & Controls • Homeostasis involve maintenance of:- • ECF pressure • ECF temperature • ECF volume • ECF osmolarity • ECF electrolytes • ECF pH

8. Homeostasis & Controls • Successful maintenance of above physiological parameters Homeostasis reestablished • Failure to maintain this parameters • Pathology • Illness • Death Figure 1-5: Homeostasis

9. Cell physiology • cells are the basic structural and functional units of all living organisms. • There are approximately 10 trillion cells and about 200 types of cells in the average adult human body

10. Cell structure

11. Nucleus • The nucleus is the most obvious organelle in any eukaryotic cell • It is enclosed in a double membrane and communicates with the surrounding cytosol via numerous nuclear pores. • It Contains all genetic information in the form of DNA..

12. The main function of the nucleus: is to control the activities of a cell through regulating gene expression. These cell activities include 1- Metabolism 2- Growth and reproduction.

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14. Ribosome • Ribosomes are cell organelles that consist of RNA and proteins. • They are responsible for protein synthesis

15. Endoplasmic reticulum • structure: • It is a special membrane structure found only in eukaryotic cells. • Two types:- • 1- smooth endoplasmic reticulum(SER) • 2- rough endoplasmic reticulum(RER)

16. 1- Smooth Endoplasmic Reticulum • It appears smooth by electronic microscopy. • Smooth ER plays different functions :- • 1-Is responsible for the production of steroied hormones and other secretary products • 2- Control of calcium release in muscle cell contraction.

18. 2-Rough Endoplasmic reticulum • It contains numerous ribosome's on its surface. • It concerned with Proteins synthesis

19. Golgi apparatus • Structure:- • Closely associated with the rough endoplasmic reticulum • For processing and package of the synthesized proteins into secretary vesicles.

21. Mitochondria • Mitochondria are membrane-bound organelles • The outer membrane is fairly smooth. • the inner membrane is highly convoluted, forming folds called cristae. • It is the primary energy • source for the cell.

22. Function: •   It has enzymes important in ATPproduction • It has a role in apoptosis(programming cell death).

23. Lysosomes • Structure : • vesicle formed from the ER and golgi apparatus . • Contain hydrolytic enzymes that are used in hydrolysis or digestion of engulfed material.

24. lysosomes

25. The cell membrane • structure • the cell membrane envelops the cell and cover it from the out side, its an elastic • structure only 7.5 to 10 nanometers thick &consist of : • Phospholipids bilayer which consist of hydrophilic & hydrophobic • Proteins • Negatively charged carbohydrates attach to the outer surface.

26. General composition of cell membrane • Proteins ……………………. 55% • Lipids ……………………….. 41% -Phospholipids … 25% -Cholesterol ……. 12%Lipids -Glycolipids…….. 4% • Carbohydrates …………… 4%

27. Cell membrane

28. Functions of the cell membrane • Support the cell. • Selective barrier • Functions of the cell membrane proteins: • Act as antigens • Act as receptors for hormones and neurotransmitters. • Act as transporter

29. THANK YOU

30. Tranport across the cell membrane

31. Transport through the cell membrane • Cell membrane is selectively permeable to some molecules. • Lipid or fat-soluble substances, e.g. O2, CO2; enter directly into cell membrane through the lipid bilayer. • Water-soluble substances, e.g. ions, glucose, water; enter through proteins of the cell membrane.

32. Transport mechanisms: • There is constant movement of O2,CO2, nutrients,electrolytes and waste products across cell membranes. • These are classified into: 1- Passive transport 2- Active transport

33. Types of membrane transport 2. Active transport • net movement across a membrane that occurs against conc gradient. (to region of higher conc) • Requires metabolic energy (ATP), & involves specific carrier proteins. 1.Passive transport • net movement of molecules & ions across a membrane from higher to lower conc. (down conc gradient) • doesn’t require metabolic energy, carrier may involves or not

34. Passive transport: • Do not consume energy. • Transport substances from areas of higher concentration to areas of lower concentration. • Either do not use membrane protein transport system(simple diffusion) or use it (facilitated diffusion).

35. Membrane protein transport system • Is a  membrane protein involved in the movement of ions and small molecules  across a biological membrane. • Mainly there are tow type of membrane transporter protein: 1- Channels Involved in transport of ions(Na, K, Ca,……) across cell membrane 2- Carriers Involved in transport of small molecules(CHO, amino acid and small protein).

36. Passive transport

37. A. Simple diffusion • Non-Carrier mediated transport. • Involves net transport down an electrochemical gradient (from higher to lower conc). • Does not need energy. • Involve transportation of lipid-soluble molecules and non polar molecules like(CO2. O2)

38. Simple diffusion Polar molecules (ex. Glucose, water) ions (ex. H+, Na+, K+) small, nonpolar molecules (ex. O2, CO2) WATER-SOLUBLE LIPID-SOLUBLE

39. B. Facilitated diffusion • Involves net transport down an electrochemical gradient (from higher to lower conc). • Does not need energy • Involve transportation of molecules that are water soluble & polar. The transport of this substances is facilitated by: 1- protein carriers (glucose, most of amino acids, & other organic molecules. 2- protein channels (ions, water)

40. Facilitated Diffusion

41. Active transport: • Consume energy in transport. • Transport substances from areas of lower concentration to areas of higher concentration. • Need carrier for transport.

42. Examples: a. Sodium-Potassium pump (Na+/K+ pump). b. calcium (Ca2+ATPase). c. hydrogen ions (H+/K+ATPase)

43. Na+/K+ Pump • Is also an ATP enzyme that converts ATP to ADP and Pi. Actively extrudes 3 Na+ & transports 2 K+ inward against conc gradient. 2 3

44. Notes :- • Transport of a substances against its chemical or electrical gradient, with consumption of energy and usage of a carrier is known as primary active transport.(e.g. Na-K Pump.) • A substances may attach to a carrier of an other substance that is transported actively, and transport with it known as secondary actively transport.(e.g.Na-Glucose co transport)

45. Na+/K+ Pump 2 3

46. Na+– glucose Co transport

47. Other transport mechanisms 1- Endocytosis(active transport): • The process by which large molecules inter the cell through the membrane • Two types: A- Phagocytosis(engulfed substance is a particular matter or bacteria). B- Pinocytosis(engulfed substance is dissolved in fluid).

48. Endocytosis fuse with lysosome for digestion phagocytosis non-specificprocess pinocytosis

49. 2- Exocytosis: • The process by which large molecules expel from the cell through the membrane. • Proteins synthesized within the cell are usually packed into secretary vesicles and secreted by exocytosis.

50. Exocytosis