General rules & guidelines Punctuality in all classesPunctuality in all classes 100% attendance100% attendance No absenteeism in assessments  university

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  • General rules & guidelinesPunctuality in all classes100% attendanceNo absenteeism in assessments university rule strictly appliedSubmission of practical reports within 1 week-delay will invite penalty by the dayInteraction with lecturer and other students (within time constraints)How to study i. Notes in class ii. Lecturers notes iii. Standard text books

  • 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 clarified4. Take down points during the lecture/tutorial which you feel are important, and also those which you dont 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 dont be alarmed by clinical terms being htrown at you. 6. Read standard prescribed text books regularly

  • Introduction to Human PhysiologyCourse Co-ordinator

    Dr Sami Al Rawas MD PhD Consultant, Clinical Physiology (Neurophysiology)

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

  • Homeostasis & Control Mechanisms - I

  • Objectives1. 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

  • 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

  • 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)

  • La fixit du milieu intrieur est la condition de la vie libre.

    The fixity of the internal

    environment is the

    condition for free life.



    1. Na+ mMol/L 145 152. K+ 5 1503. HCO3- 28 104 Cl 105 5 5. Anions (proteins) 5 406. Glucose (mg%) 100 10

    Egs of ECF: plasma; CSF; lymph; aqueous humor

  • Examples of constancy of the Internal Environment

    Body core temperature: 370C

    Arterial Blood: PaO2 100 mmHg; PaCO2 40 mmHg; pH 7.4

    Blood sugar (glucose) : 100 mg% (5 mmols)

    Blood pressure: 120/80 mmHg

    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

  • Homeostasis & Control Mechanisms -II

  • Definition :Claude Bernards 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

  • 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.

  • Feedback loops Negative & Positive Negative feedback loop requires

    Sensor (Detector): specific to variable needing to be controlledComparator (Control system): reference point for sensor to compare againstEffector: if sensor comparator Error Signal restore variable to desired level

    Biofeedback systems in maintaining homeostasis

  • Controlled condition : eg body temp.Control centre (COMPARATOR)Sets range of normal values SET POINTReceptor(sensor/detector)stimulusEffector structure that receives out put from control centreresponse

  • Feed back systems

  • Negative feedback of Blood Pressure (BP)Negative feedback: BP regulation; CO2 regulation of breathing; body temp. control; ADH & water retention by kidneys

    Controlled condition : eg BP 120/80.Control centrereceptorBPEffector(heart & blood vessels)disturbance

  • Negative feedback Control of BP

  • -Ve Feed back control of body temperature

  • Properties of negative feed back systems1. 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

  • Positive feedback systemstimulusreceptorcontrollereffectorResponse ++++++

  • Positive feedbackNormal labour

    Other examples:

    Action potential

    Coagulation of blood : cascade

  • Factors that affect performance of homeostasis mechanisms

    AgingSevere environmental conditions beyond controlNutrition statusDisease

  • Failure to maintain homeostasis:

    diseaseSymptoms: pts. complaintsSigns: observed by doctordiagnosistreatmentinvestigations homeostasis restoredsuccessfailureHomeostasis not restoredMorbidity/deathDisturbed internal environment

  • Maintenance of constancy of the Internal Environment

  • Recapitulate1. Internal environment with egs

    2. Homeostasis

    3. Feed back loops- -ve and + ve with egs

    4. What happens when homeostasis is disturbed