Introduction Instructor: Li Li Department of Physiology Jining medical college Office: 0850 physiological sciences Email: tyvm80@163.com

Introduction ⑴ Definition and Scope of Physiology. ⑵ Structure and Fundamental Characteristics of Living Organism. ⑶ Internal Environment, Homeostasis and Biorhythm. ⑷ Regulation of Body Function.

Flash Heart beat.

Figure Respiratory system.

Figure Something about digestion.

Figure Eyes and beautiful landscape.

Figure Ears and attractive melody.

⑴ Definition and Scope of Physiology Status

Definition and Scope of Physiology Physiology is the study of how living organisms work. It is a study of the normal functions of organs and organ systems of the body, the conditions under which these functions are carried out and the mechanisms by which they are achieved. Scope ① whole organism (interplay of many separate organs). ② organs and organ systems. ③ Molecule and cell.

② Salty food ③ Excretion of sodium in the urine ①

Definition and Scope of Physiology Status ① Many areas of function are still poorly understood. ② The integration of molecular biology with physiology will provide an ever-sharper view of how our bodies work. ③ Physiology is essential for the study and practice of medicine. normal function - physiology gone wrong - disease

⑵ Structure and Fundamental Characteristics of Living Organism Structure of Living Organism. The definition and multiplication and differentiation and classification of cell. Fundamental Characteristics of Living Organism. Three characteristics.

Figure How life come into being.

Structure of living organism Cell The basic units of Living Organisms. The simplest structural units into which a complex multicellular organism can be divided and still retain the functions characteristic of life are called cells. Multiplication A single cell divides to create two cell. Differentiation ① Definition: The process of transforming an unspecialized cell into a specialized cell. ② Effect: The formation of tissues and organs and organ systems.

Structure of living organism Cell Classification (according to the function they perform) ⑴ Muscle cells . ① generate the mechanical forces that produce movement. ② Be classified into skeletal, cardiac, smooth muscle cells. ③ form muscle tissue. ⑵ Nerve cells. ① initiate and conduct electrical signals. ② control the activities of other cells . ③ form nerve tissue. ⑶ Epithelial cells. ⑷ Connective tissue cells.

Structure of Living Organism Cell Classification ⑶ Epithelial cells. ① For selective secretion and absorption of ions and organic molecules and for protection. ② form epithelial tissue . ⑷ Connective tissue cells. ① Connect, anchor, and support the structures of the body. ② form connective tissue .

Figure Classification of muscle cell. ① ② ③ Figure Classification of muscle cell. ① skeletal muscle; ② cardiac muscle; ③ smooth muscle.

Figure Neuron (nerve cell).

Figure Nerve tissue.

Figure Epithelial tissue.

Figure Connective tissue.

cell tissue organ and organ system differentiation fertilized egg multiplication two cells four cells Spherical mass epithelial tissue muscle tissue nerve tissue connective tissue organs and organ systems Unspecialized cell Specialized cell cell tissue organ and organ system

Figure Urinary system.

Fundamental Characteristics of Living Organism ⑴ Metabolism . ① All the chemical reactions in all the cells of the body. ② It include the energy and material metabolism. ⑵ Excitability. Definition: The property of living organisms that permits them to react to stimuli. Manifestation: Action Potential. Assessment: Intensity and time period of stimulus. ⑶ Reproduction. Help to maintain static conditions and the automaticity and continuity of life.

⑶ Internal Environment, Homeostasis and Biorhythm. Body Fluid Compartments and Internal Environment ① The composition of body fluid. ② The definition of internal environment. Homeostasis ① The definition and characteristics of homeostasis. Biorhythm ① The definition of biorhythm and circadian rhythm. ② The effect of biorhythm on homeostasis. ③ The characteristics of biorhythm.

Figure Body fluid. plasma Interstitial fluid Extracellular fluid Internal environment Intracellular fluid Figure Body fluid.

Body Fluid Compartments and Internal Environment Composition body fluid Intracellular fluid (2/3) extracellular fluid (1/3) plasma (20%) interstitial fluid (80%) internal environment Internal environment The extracellular fluid are the ions and nutrients needed by the cells for maintenance of cellular life, and all cells live in the environment, so extracellular fluid is called internal environment.

Figure Ionic composition of body fluid.

Figure Significance of concentration difference. Intracellular fluid Extracellular fluid membrane Figure Significance of concentration difference.

Homeostasis Definition A state of reasonably stable balance between physiological variables (a stable state of internal environment). ① Homeostasis is a dynamic, not a static process. ② It can be quantified by Time-Averaged Means. ③ The maintenance of homeostasis rely on a wide variety of control system. ④ Nonhomeostatic state can have life-threatening consequences.

Figure The variability with respect to time.

Biological Rhythms Definition Circadian rhythm A characteristic of many body functions changes rhythmically. Circadian rhythm Circadian rhythm is the most common type, which cycles approximately once every 24 h. ① waking and sleeping. ② body temperature. ③ hormone concentrations in the blood. ④ the excretion of ions into urine and so on.

Biological Rhythms Effect on homeostasis Characteristic They add an anticipatory component to homeostatic control system, in effect a feedforward system. Characteristic ① They are internally driven, and they are free-running rhythms( the biological rhythms persisted in the complete absence of environmental cues). ② Environmental time cues can entrain a circadian rhythm to 24h, and they also function to phase-shift rhythms( rest the internal clock). ③ The suprachiasmatic nucleus in the hypothalamus functions as the principal pacemaker for circadian rhythms.

Figure The neural basis of body rhythms. suprachiasmatic nucleus optic chiasma Figure The neural basis of body rhythms.

⑷ Regulation of Body Function. General Characteristics of Homeostatic Control System. Feedback System. Resetting of Set Points. Feedforward Regulation. Components of Homeostatic Control System. Processes Related to Homeostasis.

General Characteristics of Homeostatic Control System ① Homeostatic control systems include nerve system and hormonal system. ② The nerve system is composed of three major parts: the sensory input portion, the central nervous system and the motor output portion. ③ The hormonal system include eight major endocrine glands that secret chemical substances called hormones. ④ The regulation of internal environment include nervous regulation and hormonal regulation and auto-regulation. ⑤ Hormonal system and nerve systems complement each other to maintain homeostasis.

Figure The nerve control system. The sensory input portion The central nervous system The motor output portion Figure The nerve control system.

Figure Endocrine system 1 Hypothalamus; 2 Pituitary gland; 3 Thyroid gland; 4 Pancreas; 5 Adrenal gland; 6 Testicle (male only); 7 Ovary (female only) ; 8 Parathyroid glands .

Feedback System Classification Negative feedback system ② Positive feedback system. Negative feedback system A change in the variable being regulated brings about responses that tend to push the variable in the direction opposite to the original change, Homeostatic control operates mainly on negative feedback. Example: the thermoregulatory system; enzymatic processes and so on. Positive feedback system An initial disturbance in the system sets off a train of events that increase the disturbance even further, less frequently seen in biological systems. Example: the process of parturition and micturition and the blood coagulation and so on.

Figure Negative feedback system. Effector Normal Figure Negative feedback system.

Figure Example of Negative feedback. BP Negative feedback Enzymes C6H12O6+O2 CO2+H2O+ATP Figure Example of Negative feedback.

Figure Effect of Negative feedback system.

Figure Positive feedback system.

Figure Process of parturition. fetus pelvis uterus oxytocin posterior pituitary gland

Resetting of Set Points The values that the homeostatic control system are trying maintain. Characteristics of Set point ① The set point for many regulated variables can be physiologically altered or reset. ② The set point can be reset in response to external stimuli such as bacteria, and it also occur on a rhythmical basis every day. ③ It is often possible to keep one property relatively constant only by moving others away from their usual set point, so it is not possible for everything to be held relatively constant by homeostatic systems.

37℃ 38℃ 37℃ fever Homeostatic control system Set point Chills and shivering fever pathogens Set point 38℃ 37℃ Create heat temperature ( Inhibits proliferation of pathogens)

Figure The set point changes in a day.

How do you feel?

Feedforward Regulation Definition Feedforward regulation anticipates changes in a regulated variable, improves the speed of the body’s homeostatic responses, and minimizes fluctuations in the level of the variable being regulated. Example ① when it becomes cold, you will wear more clothes. ② When you see the picture of delicious food, you salivate. ③Your heart beats faster before you start running.

Components of Homeostatic Control System Reflexes A reflex is a specific involuntary, unpremeditated, unlearned “built-in’’ response to a particular stimulus. Many of homeostatic control system belong to the general category of stimulus-response sequences known as reflexes. Reflex arc ( the pathway mediating a reflex) ① receptor ② afferent pathway ③ integrating center ④ efferent pathway ⑤ effector

Figure General components of reflex arc. Integrating center Receptor Effector Stimulus Response Begin Afferent pathway Efferent pathway Negative feedback Specific neurons in the brain Endocrine gland Nerve endings Smooth muscle Skeletal muscle hormone Body temperature Heat loss Heat production Figure General components of reflex arc. The present usage of reflex was not restricted to the nervous system!

Components of Homeostatic Control System Local Homeostatic Responses Like a reflex, a local response is the result of a sequence of events proceeding from a stimulus. Unlike a reflex, the entire sequence occurs only in the area of the stimulus. The significance of local responses is that they provide individual areas of the body with mechanisms for local self-regulation. Intercellular Chemical Messengers ① Hormones ② Neurotransmitters ③ Paracrine agents ④ Others.

Figure Hormones and how they function.

Figure Neurotransmitters and their function.

Figure Paracrine and autocrine agents.

Figure Other intercellular communication.

Day 1 Day 2-9 Temperature and the volume of sweat are measured. 30min Heat chamber 30min Temperature and the volume of sweat are measured. Day 2-9 Heat chamber 1-2h Temperature and the volume of sweat are measured. Results: on day 10, he sweat earlier and much more profusely than he did on day 1, and his body temperature does not rise to nearly the same degree. Conclusion: he become acclimatized to the heat.

Processes Related to Homeostasis Adaptation and Acclimatization Adaptation A characteristic that favors survival in specific environments. Homeostatic control systems are inherited biological adaptations. Acclimatization An improved ability to respond to an environmental stress, it is a type of adaptation. The representation of acclimatization is varied. Some are reversible, some are irreversible.

Figure Contrast of normal chest and barrel chest.

Figure Balance diagram for a chemical substance. Food Air Synthesis in the body GI tract Lungs Pool Storage depots Reversible incorporation into other molecules Metabolism Excretion NET GAIN DISTRIBUTION NET LOSS Figure Balance diagram for a chemical substance.

Processes Related to Homeostasis Balance in the homeostasis of chemicals ① The balance of substances in the body is achieved by matching inputs and outputs. ② Total body balance of a substance may be negative, positive, or stable.

Summary ⑴ Definition and Scope of Physiology. ⑵ Structure and Fundamental Characteristics of Living Organism. ⑶ Internal Environment, Homeostasis and Biorhythm. ⑷ Regulation of Body Function.