PHYSIOLOGY: THE CELL AND HOMEOSTASIS

1. PHYSIOLOGY: THE CELL AND HOMEOSTASIS Angelica D Francisco, MD, MSc

3. Objectives • Review the structures of the cell and their function. • Review the hierarchy of organization of the human body. • Define the “internal environment” of the cell. • Explain the importance of maintaining constant the conditions in the internal environment.

4. Objectives • Define homeostasis. • Describe the mechanism of a negative feedback system. • Explain the “gain” in negative feedback systems.

5. Objectives • Describe the mechanism of positive feedback system. • Explain how the change in positive feedback system can be useful, and potentially harmful.

6. PHYSIOLOGY HUMAN PHYSIOLOGY • THE STUDY OF THE FUNCTION AND THE REGULATION OF THE DIFFERENT ORGAN SYSTEMS OF THE BODY COMPARATIVE PHYSIOLOGY CELLULAR & MOLECULAR PHYSIOLOGY

7. THE CELL • THE BASIC LIVING UNIT OF THE BODY

9. CELL ORGANELLES MEMBRANE-BOUND CYTOSKELETON MICROFILAMENTS (ACTIN FILAMENTS) INTERMEDIATE FILAMENTS MICROTUBULES • NUCLEUS • PLASMA MEMBRANE • MITOCHONDRIA • ENDOPLASMIC RETICULUM • GOLGI APPARATUS • LYSOSOMES • PEROXISOMES

10. NUCLEUS

11. CELL MEMBRANE FUNCTIONS TRANSPORT OF SUBSTANCES CELL RECOGNITION CELL COMMUNICATION TISSUE ORGANIZATION ENZYMATIC ACTIVITY CELL MORPHOLOGY

12. MITOCHONDRIA

13. MITOCHONDRIA & ATP

14. ATP & CELL METABOLISM

15. ENDOPLASMIC RETICULUM

16. ENDOPLASMIC RETICULUM ROUGH ER SMOOTH ER ABSENCE OF RIBOSOMES FUNCTION SYNTHESIS OF FATS & LIPIDS DETOXIFICATION OF SUBSTANCES SEQUESTERS Ca++ SARCOPLASMIC RETICULUM • PRESENCE OF RIBOSOMES • CELLS ACTIVE PROTEIN SYNTHESIS & SECRETION FUNCTION • PROTEIN SYNTHESIS • TRANSLATION OF mRNA

17. GOLGI APPARATUS

18. GOLGI APPARATUS FUNCTION • POST-TRANSLATIONAL MODIFICATION OF PROTEINS • PACKAGES PROTEINS FOR DELIVERY

19. SECRETORY GRANULES

20. PROTEIN & LIPID SYNTHESIS

21. LYSOSOMES • CONTAINS DIGESTIVE ENZYMES FUNCTION • DEGRADATIVE FUNCTION • eg. MACROPHAGE

22. PHAGOCYTOSIS http://student.ccbcmd.edu/courses/bio141/lecguide/

23. PEROXISOMES • CONTAINS OXIDATIVE ENZYMES FUNCTION • OXIDIZE FATTY ACIDS • DETOXIFY COMPOUNDS • eg. LIVER CONVERSION OF ETHANOL TO ACETALDEHYDE

24. CYTOSKELETON FUNCTION • MAINTAIN CELL STRUCTURE • CHANGE CELL SHAPE • CELL MOTILITY

25. CYTOSKELETON ACTIN MICROFILAMENTS • LOCOMOTION • LINK TO ADJACENT CELLS • ZONULA ADHERENS/OCCLUDENS INTERMEDIATE FILAMENTS • INTRACELLULAR STRUCTURE • KERATIN IN EPITHELIAL CELLS • EXTRACELLULAR LINKAGE • DESMOSOMES & HEMIDESMOSOMES

26. MICROTUBULES

27. MICROTUBULES FUNCTIONS • INTRACELLULAR TRANSPORT OF VESICLES • W/ MOTOR PROTEINS: KINESIN & DYNEIN • CHROMOSOME MOVEMENT IN MITOSIS/ MEIOSIS • MOVEMENT OF CILIA & FLAGELLA

28. LYSOSOMAL DISEASES • ABSENCE OF LYSOSOMAL ENZYMES TAY-SACH’S DISEASE • HEXOSEAMINIDASE A • ACCUMULUATION OF GANGLIOSIDE IN NEURONS LORENZO’S OIL: ACCUMULATION OF VERY LONG CHAIN FATTY ACIDS,VLCFCAs

29. MICROTUBULES & CANCER • UNCONTROLLED MITOSIS IN TUMOR CELLS ANTITUMOR DRUGS • VINCRISTINE • PREVENTS FORMATION OF MICROTUBULES • TAXOL • STABILIZES MICROTUBULES

30. LEVELS OF ORGANIZATION David Shier, Jackie Butler, Ricki Lewis Hole’s Human Anatomy and Physiology

31. LEVELS OF ORGANIZATION • TISSUES • 4 TYPES EPITHELIUM, CONNECTIVE TISSUE, MUSCLE & NERVOUS TISSUE • ORGANS • SYSTEMS

32. CARDIOVASCULAR SYSTEM RESPIRATORY SYSTEM DIGESTIVE SYSTEM RENAL SYSTEM REPRODUCTIVE SYSTEM MUSCULO-SKELETAL SYSTEM ENDOCRINE SYSTEM NERVOUS SYSTEM IMMUNE SYSTEM ORGAN SYSTEMS & THEIR FUNCTIONS

33. HOMEOSTASIS WALTER CANNON (1871-1945) HOMEOSTASIS: THE RELATIVELY CONSTANT STATE OF THE COMPOSITION OF THE INTERNAL ENVIRONMENT, ACHIEVED THROUGH HIGHLY COORDINATED PROCESSES. 1926

34. HOMEOSTASIS CLAUDE BERNARD (1813-1878) “milieu interieur”, 1887 • INDEPENDENCE OF LIVING BODY FROM SURROUNDING ENVIRONMENT • INTERNAL vs. EXTERNAL ENVIRONMENT “It is the stability of the internal environment that is the condition of a free and independent life.”

35. HOMEOSTASIS “It is the fixity of the internal environment that is the condition of a free and independent life. All the vital mechanisms, however varied they may be, have only one object, that of preserving (constant) the conditions of life in the internal environment.” Claude Bernard

36. CELL EXTRACELLULAR FLUID, ECF

38. TOTAL BODY WATER,TBW • 60% OF BODY WEIGHT • 40% IN INTRACELLULAR FLUID COMPARTMENT (ICF) • 20% IN EXTRACELLULAR FLUID COMPARTMENT (ECF) • PLASMA, 4% • INTERSTITIAL FLUID, 16%

39. INTRACELLULAR FLUID, ICF 40%TBW EXTRACELLULAR FLUID, ECF 20% TBW 40% BLOOD/PLASMA 4% INTERSTITIAL FLUID, 16%

40. COMPOSITION OF ECF & ICF

41. EXTERNAL & INTERNAL ENVIRONMENT Vander, Sherman, Luciano’s Human Physiology, 9th ed

42. HOMEOSTASTIC REGULATION • CONCENTRATION OF O2 & CO2 • pH OF INTERNAL ENVIRONMENT, 7.4 • CONCENTRATION OF NUTRIENTS AND WASTE PRODUCTS • CONCENTRATION OF SALT AND OTHER ELECTROLYTES • VOLUME AND PRESSURE OF the ecf

43. HOMEOSTATIC CONTROL SYSTEMS DISTURBANCE FEEDBACK CONTROLLER SETPOINT + CONTROLLED VARIABLE EFFECTOR - - CLOSED LOOP SENSOR + RHOADES RA & TANNER GA. MEDICAL PHYSIOLOGY

44. CONTROL SYSTEMS • NEGATIVE FEEDBACK • A DISTURBANCE ELICITS A RESPONSE THAT RESULTS IN AN EFFECT THAT IS OPPOSITE THAT OF THE CHANGE • eg. THERMOSTAT

45. CONTROL SYSTEMS EXAMPLE: BODY TEMPERATURE NORMAL, 37OC w/o, 20OC, ROOM TEMPERATURE with 36.5OC

46. ROOM TEMPERATURE HEAT LOSS FROM BODY BODY TEMPERATURE CONSTRICTION OF SKIN BLOOD VESSELS CURLING UP SHIVERING HEAT LOSS FROM BODY HEAT PRODUCTION RETURN OF BODY TEMPERATURE TOWARD ORIGINAL VALUE

47. CONTROL SYSTEMS “SET POINT” OR BASELINE RESETTING OF “SET POINT” IN RESPONSE

48. Vander, Sherman, Luciano’s Human Physiology, 6th ed

49. NORMAL RANGE OF VALUES

50. CONTROL SYSTEMS NORMAL RANGE OF VALUES WITHIN NARROW LIMITS eg. BODY TEMPERATURE, 36.5-37.5 oC APPROXIMATE NONLETHAL LIMITS MAXIMUM LIMITS WITHOUT CAUSING DEATH FOR SHORT PERIODS OF TIME eg. IN CARDIAC ARREST, THERAPEUTIC HYPOTHERMIA, 33-36 oC