Presentation on theme: "Institute of Physiology Medical School of SDU Tel (lab)"— Presentation transcript:
1Institute of Physiology Medical School of SDU Tel 88381175 (lab) LIU Chuan Yong刘传勇Institute of PhysiologyMedical School of SDUTel (lab)(office)Website:
2Introduction to Physiology Chapter 1Introduction to Physiology
3Section I What is Physiology? Physiology: biological sciencesdealing with the normal life phenomena exhibited by all living organisms.Human physiology: basic sciencesdealing 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.
4Human PhysiologyPhysiology: (Greek) The study of nature, the involvement of Physics and Chemistry.The basis forPathophysiologyPharmacologyImmunologyBiochemistryMicrobiology
5Why do we study Physiology? Understand the physiologic principle underlie normal function in order to cure the impairments.
6Organization of the human body Different Level of Physiological ResearchOrganization of the human bodyOrganisms(Human body)OrgansystemsOrgansTissuesCells
10Extracellular fluids 1. Interstitial fluid Intracellularfluid2. Plasma1. Interstitial fluid3. Fluid of special compartments: pericardial fluid, pleural fluid, cerebrospinal fluid
11HomeostasisMaintenance of Relatively Constant Chemical/Physical Conditions of the internal environment.Claude Bernard__ The father of modern Physiology...The internal environment remains relatively constant though there are changes in the external environmentstable =/= rigidity, can vary within narrow limit (normal physiological range)The golden goal of every organ : to maintain homeostasis (concept of REGULATION)
12Normal Physiological ranges In fasting bloodArterial pHBicarbonate mEq/LO2 content ml/100 mlTotal lipid mg/100 mlGlucose mg/100 ml
13Homeostasis & Controls Successful compensationHomeostasis reestablishedFailure to compensatePathophysiologyIllnessDeath
14Section 3 Regulation of the Body Functions Regulation- the ability of an organism to maintain a stable internal conditions in a constantly changing environment-Three types:1. 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
15- Example: baroreceptor reflex of arterial blood pressure - Characteristics: response fast; acts exactly or locally, last for a short time3. Autoregulation – a tissue or an organ can directly respond to environmental changes that are independent of nervous and hormonal controlCharacteristics：Amplitude of the regulation is smaller than other two types.Extension of the effects is smaller than other two types.In the human body these three regulations have coordinated and acts as one system, “feedback control system”.
16Section 4 Control System Non-automatic ControlOpen-loop system2. Feedback ControlThe word “feedback” means a process in which a part of output (feedback signal) from controlled organ returns to affect or modify the action of the control system.Feedback control mechanism consists of two forms: negative and positive feedback control.
17Negative feedbackThe feedback signals from controlled system produces effect opposite to the action of the control system.The opposite effect is mainly “inhibitory action”.
18Control Systems (Negative feedback in cardiovascular and endocrine systems) ErrorSignalComparatorControllerReferenceSignalEffectorsRegulatedVariableFeedbackSignalSensor
19Negative Feedback: Inhibitory. Stimulus triggers response to counteract further change in the same direction.Negative-feedback mechanisms prevent small changes from becoming too large.
21Positive feedbackThe feedback signal or output from the controlled system increases the action of the control systemExamples: Blood clotting, Micturition, defecation, Na+ inflow in genesis of nerve signals, Contraction of the uterus during childbirth (parturition).
22Positive Feedback: Stimulatory. Stimulus trigger mechanisms that amplify the response and reinforces the stimulus.
23Importance:1) Enhance the action of original stimulus or amplify or reinforce change, promote an activity to finish2) It is known as a vicious circle because it can lead to instability or even death
243. Feed-forward controlConcept: 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
25Significance 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).