1. General rules & guidelines Punctuality in all classesPunctuality in all classes 100% attendance100% attendance No absenteeism in assessments  university rule strictly appliedNo absenteeism in assessments  university rule strictly applied Submission of practical reports within 1 week-delay will invite penalty by the daySubmission of practical reports within 1 week-delay will invite penalty by the day Interaction with lecturer and other studentsInteraction with lecturer and other students (within time constraints) (within time constraints) How to studyHow to study i. Notes in class i. Notes in class ii. Lecturer’s notes ii. Lecturer’s notes iii. Standard text books iii. Standard text books

2. 1. Be regular in attending classes. Your lecturer has taken a lot of pains to prepare the subject. You must draw maximum benefit from this.1. Be regular in attending classes. Your lecturer has taken a lot of pains to prepare the subject. You must draw maximum benefit from this. 2. If you have doubts, have them clarified2. If you have doubts, have them clarified 4. Take down points during the lecture/tutorial which you feel are important, and also those which you don’t seem to understand. Compare your notes with the information in the book, and make whatever additions you feel are important. Inn this manner you can compile your own information on a given topic and use it for the exams.4. Take down points during the lecture/tutorial which you feel are important, and also those which you don’t seem to understand. Compare your notes with the information in the book, and make whatever additions you feel are important. Inn this manner you can compile your own information on a given topic and use it for the exams. 5. You are now studying a clinically oriented syllabus. So don’t be alarmed by clinical terms being htrown at you.5. You are now studying a clinically oriented syllabus. So don’t be alarmed by clinical terms being htrown at you. 6. Read standard prescribed text books regularly6. Read standard prescribed text books regularly

3. Introduction to Human Physiology Course Co-ordinator Dr Sami Al Rawas MD PhD Consultant, Clinical Physiology (Neurophysiology)

4. Introduction: Text Book i. Principles of Anatomy & Physiology. Tortora & Grabowsky. Wiley & Sons; 2003 Reference books i.. Text Book of Medical Physiology. Guyton & Hall. 12 th edn. Saunders, London. 2011 Ii. Ross ands Wilson. Anatomy and Physiology in Health and Disease. 10 th Edn. Churchill Livingstone. 2006

5. Homeostasis & Control Mechanisms - I

6. Objectives 1. Explain the meaning of the term internal environment and homeostasis (Giving examples) and appreciate the importance of constancy of the milieu interior. 2. State that homeostasis involves maintaining the internal environment at a constant level or between narrow limits. 3. Explain that homeostasis involves monitoring levels of variables and correcting changes which may occur under various situations –Physiological or Pathological 4. Understand what is meant by controlled variable and set point. 5. Explain the feed back mechanisms in control system i.e negative feedback mechanisms. 6. List examples of negative feed back systems, and describe 2 such 7. Give an example of positive feedback mechanisms e.g. parturition (child birth ). 8. Understand that disease alters homeostasis of the internal environment and may cause death

7. Definition of Physiology “Is the science of how the body systems work, and the ways in which their integrated cooperation maintains life and health of an individual” Pathology is the study ofabnormsalities in body tissues and how they affect body functions and cause illness Pathophysiology is how the body function resposnds to Pathology

8. Atoms Molecules Organelles Cells Tissues Organs Systems Organism

9. Integumentary (Skin) Physiology (system) Cardiovascular Physiology (system) Respiratory Physiology (system) Gastrointestinal Physiology (system) Renal Physiology (system) Reproductive Physiology (system) Musculo-skeletal Physiology (system) Neurophysiology Nervous system Endocrine Physiology (system) Immune Physiology (system)

11. “La fixité du milieu intérieur est la condition de la vie libre.” “The fixity of the internal environment is the condition for free life.”

12. What is the INTERNAL ENVIRONMENT?

13. ECF ICF 1. Na + mMol/L 145 15 2. K + 5 150 3. HCO3 - 28 10 4 Cl 105 5 5. Anions (proteins) 5 40 6. Glucose (mg%) 100 10 Egs of ECF: plasma; CSF; lymph; aqueous humor

14. Examples of constancy of the Internal Environment 1.Body core temperature: 37 0 C 2.Arterial Blood: PaO 2 100 mmHg; PaCO 2 40 mmHg; pH 7.4 3.Blood sugar (glucose) : 100 mg% (5 mmols) 4.Blood pressure: 120/80 mmHg 5.Electrolytes: Na + 140 mmol/L; K + 4 mmol/L pH : stomach= 2-4, small intestinal pH about 8 urine about 6 All body cells and systems contribute towards this

15. Homeostasis & Control Mechanisms -II

16. Definition : Claude Bernard’s “Milieu Interieur” or the Internal Environment: Maintenance of the constancy of this, which is the EXTRA CELLULAR fluid of the body, is called HOMEOSTASIS Concept by Walter Canon Bottom line in Physiology: Maintain Homeostasis

17. Process of maintaining the composition of the internal body compartments within fairly strict limits (ion concentrations, pH, osmolarity, temperature etc). Require regulatory mechanisms to defend against changes in external environment and changes due to activity. Cellular homeostasis - intracellular fluid composition Organismal homeostasis - extracellular fluid composition. Control system designed to maintain level of given variable (concentration, temperature, pressure) within defined range following disturbance.

18. egative & PositiveFeedback loops  Negative & Positive Negative feedback loop requires Negative feedback loop requires  : specific to variable needing to be controlledSensor (Detector): specific to variable needing to be controlled reference point for sensor to compare againstComparator (Control system): reference point for sensor to compare against if sensor  comparator  Error Signal  restore variable to desired levelEffector: if sensor  comparator  Error Signal  restore variable to desired level Biofeedback systems in maintaining homeostasis

19. Controlled condition : eg body temp. Control centre (COMPARATOR ) Sets range of normal values  SET POINT Receptor (sensor/detector) stimulus Effector structure that receives out put from control centre response

20. Feed back systems

21. Negative feedback of Blood Pressure (BP) Negative feedback: BP regulation; CO 2 regulation of breathing; body temp. control; ADH & water retention by kidneys Controlled condition : eg BP 120/80. Control centre receptor BP Effector ( heart & blood vessels) disturbance

22. Negative feedback Control of BP

23. -Ve Feed back control of body temperature

25. Properties of negative feed back systems 1. They have a GAIN  Effectiveness 2. Usually fast response 3. Incomplete correction  leaves behind an ERROR Ideal Systolic BP : 120mmHg Stimulus(shock) changes BP to 60mmHg Coorected BP after feed back mechanism : 90mmHg ERROR: 30 mmHg

26. Positive feedback system stimulus receptor controller effector Response +++ +++

27. Positive feedback Normal labour Other examples: Action potential Coagulation of blood : cascade

28. Factors that affect performance of homeostasis mechanisms Aging Severe environmental conditions beyond control Nutrition status Disease

29. Failure to maintain homeostasis: disease Symptoms: pts. complaints Signs: observed by doctor diagnosis treatment investigations homeostasis restored success failure Homeostasis not restored Morbidity/ death Disturbed internal environment

30. Maintenance of constancy of the Internal Environment

31. Recapitulate 1. Internal environment with egs 2. Homeostasis 3. Feed back loops- -ve and + ve with egs 4. What happens when homeostasis is disturbed