1. Introduction to Human Physiology
XIA Qiang（夏强）, MD & PhD
Department of Physiology
Room 518, Block C, Research Building
School of Medicine, Zijingang Campus
Tel: ☆ (Undergraduate School),
(Medical School)

2. Graduate Attributes and Capabilities
Attitudes
Knowledge
Skills

3. Learning Philosophy I hear and I forget, I see and I remember,
I do and I understand.

4. Handheld device software
Epocrates: drugs manual
>3300 drugs
More than 45% medical doctors used
DynaMed: evidence based medicine database

7. Course Structure Lectures: 80 academic hours Practicals: 64 a.h.
5 a.h./week
2 a.h. on Mon., 3 a.h. on Wed.
Practicals: 64 a.h.
4 a.h./week
Begin from second week

8. Evaluation Participation: 5% Practical reports: 15%
Weekly assessments (from Summer Week 2 on), mini-tests at lecture & midterm exam: 30%
Final examination: 50%
“Double pass” policy:
Total >= 60
Final examination >= 60
Weekly assessments & midterm exam >= 60

9. Recommended textbook
Widmaier EP, Raff H, Strang KT (2010 or later) Vander’s Human Physiology: The Mechanisms of Body Function, McGraw-Hill.

10. Course website
Course website:
Demo

11. Human Physiology
Specific characteristics, functions and mechanisms of the human body that make it a living being
What ?
How ?

12. Body Components Differentiated Cells - specialized function
Tissues - groups of cells with related function (muscle, nervous, connective, & epithelium)
Organ- functional unit
Organ system – several organs act together to perform specific function
skin = barrier
entry = respiratory & GI
transport = CV & diffusion
exit = renal & GI

13. Fluid Compartments ICF ISF plasma organs external environment
internal environment

14. Body Fluid = 60% of Body Weight (BW)
Internal environment
Body Fluid = 60% of Body Weight (BW)
Intracellular Fluid
2/3, 40% of BW
Extracellular Fluid
1/3, 20% of BW
Plasma 5% of BW
Interstitial Fluid
15% of BW
70 kg Male, 42 L

15. Extracellular Fluid=
Internal Environment

16. Homeostasis
Homeostasis (from the Greek words for “same” and “steady”):
maintenance of static or constant conditions in the internal environment
Central theme of physiology
Walter B. Cannon

17. Components of Homeostasis:
Concentration of O2 and CO2
pH of the internal environment
Concentration of nutrients and waste products
Concentration of salt and other electrolytes
Volume and pressure of extracellular fluid

18. How is homeostasis achieved?
----Regulation
Body's systems operate together to maintain homeostasis:
Skin system Skeletal and muscular system
Circulatory system Respiratory system
Digestive system Urinary system
Nervous system Endocrine system
Lymphatic system Reproductive system

19. Homeostasis and Illness

20. Regulation of body functions
Nervous Regulation
Humoral Regulation
Autoregulation

21. Nervous regulation
Reflex
Knee jerk reflex

22. Reflex Arc Receptor Afferent (sensory) nerve
Reflex center (brain or spinal cord)
Efferent (motor) nerve
Effector

23. Humoral regulation
Endocrine cells
Hormone
Traditional description of humoral regulation by hormone
Receptor

24. Endocrine action: the hormone is distributed in blood and binds to distant target cells
Paracrine action: the hormone acts locally by diffusing from its source to target cells in the neighborhood
Autocrine action: the hormone acts on the same cell that produced it

25. Neuroendocrine
(Neurosecretion)
Vasopressin
Oxytocin

27. Autoregulation
Definition: Intrinsic (independent of any neural or humoral influences) ability of an organ to maintain a constant blood flow despite changes in perfusion pressure
Mechanism: Stretch-activated constriction of vessels
Significance: Maintenance of near-constant cerebral, renal and coronary blood flow

28. 80~180 mmHg

29. Control systems of the body
CYBERNETICS
or Control and Communication in the Animal and the Machine (MIT Press 1948)
Norbert Wiener ( )
Originator of Cybernetics

30. 1. Non-automatic Control System
Open-loop system
Seldom seen under physiological conditions
Stress
Control Center
Effectors
Stimulus
Response

32. 2. Feedback Control System
Control Center
Effectors
Stimulus
Response
Closed-loop system
Automatic control
Negative feedback
Positive feedback

33. Negative feedback: common
A change in a condition leads to responses from the effectors which counteracts that change

34. Examples:
Regulation of blood pressure,
Regulation of body temperature,
Regulation of hormone release…

35. Gain of the negative feedback:
The degree of effectiveness with which a control system maintains conditions
Correction
Error
Gain=

36. Positive feedback: uncommon
A change in a condition leads to responses from the effectors which amplifies that change +

37. Examples:
Child birth
Micturition
Blood coagulation
Vicious circle under pathophysiological conditions…

38. 3. Feed-forward Control Often seen in nervous system Rapid
Adaptive control
Examples: some muscle contraction, conditioned reflex
Control Center
Effectors
Stimulus
Response
Monitor
Disturbance

40. Summary Terms: Regulation of body functions Internal environment
Homeostasis
Negative feedback
Positive feedback
Regulation of body functions

41. THANK YOU FOR YOUR ATTENTION!