Physiology definition

Physiology definition

1. Introduction to Physiology

2. What is Physiology? Physiology : biological sciences dealing with how the body functions at the various levels of organization / Study of the function of all living organism . Human physiology : preclinical sciences dealing with normal life phenomena of the human body. Goal of physiology : explain the physical and chemical factors that are responsible for the origin, development and progression of life.

3. Physiology …………… Physiology: (phy, nature; logos, discourse) Thales of Miletos First physiologist Modern sense - William Harvey(1578-1657) “Physiology” = Herman Boerhave (1660-1738) Physiology emerged from the ancient scientific and philosophical disciplines of the Ayurveda (“science of life”) The Father of modern Physiology: Claude Bernard (1813-1878) Nepali : “ मानब शारीरक्रिया बिज्ञान ” 

4. Human Physiology Deals-Molecules - Sub cellular component - Organ-system & their interaction The basis for -Pathology - Pharmacology - Immunology - Biochemistry - Microbiology Human physiology (medical Physiology) links the Basic Medical sciences to Clinical Medicine

5. Why do we study Physiology ? Understand the physiologic principle underlie normal function in order to cure the i mpairments.

6. Organization of the human body Cells Tissues Organs Organ systems Organisms (Human body)

7. Multicellular organism: Cell-tissue-organs-systems The optimum condition/constancy required for smooth functioning of the body : Homeostasis (Walter canon) “Dynamic self-regulation”. All systems function together to help the human body to maintain homeostasis “A person who is in good health is in a state of Homeostasis” Organization of the human body

8. Stable Internal environment ‘milieu interieur’ (Claude Bernard) = Homeostasis Role of System for the regulation of homeostasis 1.ECF fluid transport system ( circulatory system ) 2.Origin of nutrients in ECF ( respiratory/ GI system ) 3.Changes in usable form –( Hepatobiliary system ) 4.Removal of metabolic end product – ( kidney, respiratory) 5.Regulation of Body function ( NS, Endocrine, immune, Integumantary, reproduction ) Organization of the human body

9. Homeostasis 1. Dynamic equilibrium 2. In spite of multiple stimuli 3. Maintained by negative feedback The feedback signals from controlled system produces effect opposite to the action of the control system.

10. Homeostasis & Controls Successful compensation Homeostasis reestablished Failure to compensate Pathophysiology Illness Death

11. Regulation of the Body Functions Regulation - the ability of an organism to maintain a stable internal conditions in a constantly changing environment Three types: Chemical (hormonal) Regulation- a regulatory process performed by hormone or active chemical substance in blood or tissue. -It response slowly, acts extensively and lasts for a long time. 2. Nervous Regulation- a process in which body functions are controlled by nerve system - Pathway: nerve reflex - Types: unconditioned reflex and conditioned reflex

12. - Example: baroreceptor reflex of arterial blood pressure Characteristics : response fast; acts exactly or locally, last for a short time 3. Autoregulation – a tissue or an organ can directly respond to environmental changes that are independent of nervous and hormonal control Characteristics ： Amplitude of the regulation is smaller than other two types. Extension of the effects is smaller than other two types. Regulation of the Body Functions

13. Basic components of a feedback system A receptor :detects changes (stimuli) in the body. A control center : determines a set point for a normal range. An effector : causes the response determined by the control center.

14. Negative feedback

15. Characteristics of Control system Negative feedback system - Effector response is – ve to the initiating Stimulus ( disturbance) = BP control, temperature regulation, regulation of oxygen, carbon dioxide Negative feedback

16. Positive feedback system A REGULATORY MECHANISM IN WHICH THE RESPONSE TO A STIMULUS, IN A CONTROL SYSTEM, CAUSES THE CONTROLLED VARIABLE TO MOVE FARTHER FROM THE SET POINT.

17. Positive feedback system An unusual of phenomena of control system Sex hormone during ovulation Contraction of the uterus during childbirth (parturition). Defecation Blood coagulation Na+ inflow in genesis of nerve signals

18. Importance - does not lead to stability 1) Enhance the action of original stimulus or amplify or reinforce change, promote an activity to finish 2) It is known as a vicious circle because it can lead to instability or even death Positive feedback system

19. Feed-forward control Concept: a direct effect of stimulus on the control system before the action of feedback signal occurs. Here the direct effect of the stimulus is termed disturb signal or interfere signal . Example: Shivering before diving into the cold water

20. Significance of Feedback-forward : adaptive feedback control. makes the human body to foresee and adapt the environment promptly and exactly (prepare the body for the change).

21. Additional complexities in control system Servomechanism -Set point not fixed ( stretch reflex) Coupling Two control system couple = hypoxia- RR, BP Physiological Condition Childhood, Adult, Old, Male, Female, Pregnancy, Lactation, Rest, Exercise, Environmental temperature, Altitude Feedback system

22. At the end of phase I How does the body function during the normal demands of everyday life, and during stressful situations like exercise, or working in extreme environments? How oxygen is supplied to the body? How general and special sensory information are perceived and processed by the body? How hunger and thirst is regulated?  How reproduction and higher intellectual functions like learning and memory is coordinated?  How blood pressure and body temperature is maintained ?  How do body systems fail in diseases such as diabetes, hypertension, kidney failure and neurodegeneration ? How might these conditions be alleviated and cured? Identification of human blood cells, their characteristics, blood grouping, and other practical skills of Hematology Clinical Examination of Sensory and Motor System Blood Pressure Measurement Estimation of Oxygen Consumption Reproductive Biology and Experimental Endocrinology Recording and interpretation of : Electrocardiography (ECG) Electromyography (EMG) , Electroencephalography (EEG) , Autonomic Function Test (AFT)

23. Knowledge of physiology will be achieved by as per TU curriculum Conventional Learning Experience (CLE) Laboratory exercise ( Labex ), Practical Problem Base Learning (PBL) Correlation seminar as per departmental activities : Small Group Discussion (SGD), tutorial Continue Medical Education (CME) Journal Club Research Organization of Human Physiology Department Undergraduate teaching lab: Hematology laboratory Clinical Physiology laboratory Skill laboratory Research lab: Neuroendocrine laboratory High altitude laboratory Animal house