生理学课件：生理绪论

1、Physiology （生理学）Introduction (绪论)Why must the medical students study human physiology?Human physiology is the main component in the study of medicine. For example: why can heart automatically beat? When a patient is in a hospital, their physiology has gone wrong. Medical science development is close

2、ly related to physiology. Physiology provides the theories to explain many diseases. Clinical practices test whether the physiological theories are correct or not and promote development of physiology.Methods of physiological research 生理学的研究方法促胰液素的发现（Bayliss & Starling， 1902）Physiology is an experim

3、ental scienceOtto Loewi (奥托 . 洛伊维 ) 1936 Nobel PrizeAcute experiment in vitro (急性离体实验) at organic levelAcute experiment in vitro at tissue/molecular levelChronic experiment in vivo人体实验Levels of physiological research生理学研究的不同水平(2) Cellular & molecular level （General Physiology， Cellular and Molecular

4、 Physiology） 细胞和分子水平The basic living unit of the body is the cell, and each organ is an aggregation of many different cells held together by intercellular supporting structures. Help to understand the function of the organ. Organic & systemic level （Organ Physiology） 器官和系统水平The goals are to explore

5、the effects of organs and systems for human body and how to perform their activities, and the affecting factors. (3) Integrative level （Integrative Physiology） 整体水平 The aims are to study interactions among organs and systems, and interaction between human body and environment.Translational Medicine第

6、二节 机体的内环境和稳态Internal environment and HemeostasisOrgan Systems are Integrative. All of the systems in an organism are interconnected. 体液的分隔和相互沟通The Bodys External Environment(外环境)Interior of body separated from external environment by a layer of epithelial tissue. Example: Lumen of respiratory system

7、The Bodys Internal Environment 内环境Internal environment = fluid surrounding cells= Extracellular fluid Claude Bernard 1852年提出Homeostasis (稳态)Minority of mammalian cells are in direct contact with external environmentMajority of cells are sheltered by extracellular fluidWhen conditions outside the bod

8、y change, this is reflected in the composition of the ECF, this in turn affects the cellsHomeostasis - the ability to maintain a relatively stable internal environment in an ever-changing outside world. “Relatively stable” means that the internal environment of the body is in a dynamic state of equi

9、librium. Does not mean that composition, temperature, and other characteristics are absolutely unchangingHomeostasis is essential for survival and function of all cellsU.S.A Physiologist Walter Cannon combined “Homeo” with “stasis” to make up the term, Homeostasis. To keep cells under optimum condit

10、ions for function and survivalWhy do we need a stable, internal environment?Living cells can function only within a narrow range of such conditions as temperature, pH , ion concentrations, and nutrient availability, yet living organisms must survive in an environment where these and other conditions

11、 vary from hour to hour, day to day, and season to season. Organisms therefore require mechanisms for maintaining internal stability in spite of environmental change. So, there is a set point. The internal environment can be altered around the set point within a tolerable (narrow) range of values. T

12、his is what happens in your body. When the deviation is too great, the body has to detect it first, and then correct it. Homeostasis-the key concept to physiological control. A Central Organizing Principle of PhysiologyHomeostasis is the physiological process that maintains equilibrium in our physio

13、logical activity and allows us to function normally. One of the primary prerequisites for being a healthy individual is the ability to maintain homeostasis。 Deviations from the normal values are indicators of abnormal function Normal Values Neuroregulation（神经调节） * Definition & the characteristics *

14、Reflex & reflex arc Humoral regulation（体液调节） * Definition & the characteristics * Hormone & its secretory forms Telecrine, paracrine, neurosecretion, etc. Autoregulation（自身调节） * Definition & the characteristics第三节 机体生理功能的调节Regulation of physiological functionControls and coordinates bodily activitie

15、s that require rapid responsesDetects and initiates reactions to changes in external environmentIt is completed under CNS by reflex that the regular response was made to internal or external stimuli under CNS.Reflex arc:Sensor, afferent neuron, reflex center, efferent neuron, and effector.Neuroregul

16、ation （神经调节）有些内分泌腺本身直接或间接地受到神经系统的调节，在这种情况下，体液调节是神经调节的一个传出环节，是反射传出道路的延伸。这种情况可称为神经-体液调节。神经体液调节实例： 肾上腺髓质受交感神经节前纤维的支配，交感神经兴奋时，引起肾上腺髓质释放肾上腺素和去甲肾上腺素，从而使神经与体液因素共同参与机体的调节活动。 Neurohumoral regulation(神经-体液调节) Many endocrine glands are not independent on nervous system, they are regulated directly or indirectl

17、y by nervous system, so the humoral regulation is believed as one loop of nervous system, i.e. Neurohumoral regulation . Arterial blood pressure contraction of the vascular smooth muscle constriction of the blood vessel the blood flow relatively constantThe regulation is not dependended on nervous s

18、ystem or homoral regulation. The cells or tissues themselves can response to stimulus.肾动脉灌注压在80-180mmHg范围变动时，肾血流量基本保持稳定，从而保证肾泌尿活动在一定范围内不受动脉血压改变的影响。Range of regulation BP: 80 180 mmHg血流阻力同微小动脉管半径的四次成反比，说明血管口径只要稍有缩小,其阻力就大大增加。生理功能的调节 神经调节（neuroregulation） 1概念:由神经反射参与的调节 2基本方式：反射（reflex） 1）概念:在中枢神经系统参与下

19、，机体对刺激发生的规律性反应 2）结构基础（反射弧） 3）分类 3作用特点 体液调节（humoral regulation）1概念: 体液因子(激素,化学物质) 体液途径器官组织2作用方式 3作用特点 4神经与体液调节比较 自身调节（autoregulation） 1概念：组织细胞不依赖于神经或体液调节而产生的适应性反应。2举例：脑血流量调节; 肾血流量调节3特点：涉及范围小;调节幅度小作 用机体调节的主要方式,起主导作用反应速度迅速作用部位准确作用范围局限持续时间短暂 反应速度缓慢 作用部位广泛 作用范围弥散 持续时间持久 Homeostasis is continually being d

20、isrupted byExternal stimuli heat, cold, lack of oxygen, pathogens, toxinsInternal stimuliBody temperatureBlood pressureConcentration of water, glucose, salts, oxygen, etc.Physical and psychological distressesDisruptions can be mild to severeIf homeostasis is not maintained, death may resultHomeostas

21、is is disrupted by ANY change in the environment! Biocybernetics （生物控制论）is the application of cybernetics to the biological science.Cybernetics has close connections to biology and medicineDefinition by Norbert Wiener: Cybernetics （控制论） is the science of communication and control in machines and liv

22、ing organisms.Control needs communication to obtain signalsControl is based on the transmission of information.How to keep Homeostasis ? Control systems of the body体内的控制系统Control system in the body Feedback control system：Negative feedback system； Positive feedback system Feed-forward control system

23、生理功能的反馈控制系统和前馈控制系统示意图Negative Feedback Control of RoomTemperatureNegative Feedback-promotes stability :Positive Feedback正反馈Figure 1.6In positive feedback systems, the output enhances or exaggerates the original stimulus正反馈没有纠偏的效果，一般对稳态的维持不发挥作用。病理情况下的正反馈心衰 心脏收缩力低下 射血无力 心室博出量减少 心室残留血量增多 心室扩大、耗氧量增多 心脏负担加重、收缩力进一步减弱 更严重的心衰负反馈与正反馈的比较比较项负反馈正反馈反馈信息方向与控制信息相反与控制信息相同对控制系统的作用制约、抑制、减弱其活动再生、促进、加强其活动作用效果减小偏差信息减弱控制信息减小输出变量增大偏差信息增强控制信息加大输出变量输出与输入关系输出制约输入输出强化输入Feed-forward controllers require learning from experienceFeed-forw