Introduction to Human Physiology
XIA Qiang, M.D. & Ph.D.
Department of Physiology
Room 518, Block C, Research Building
School of Medicine, Zijingang Campus
Email: [email protected]
Tel: 88208252
Course Structure
• Lectures: 80 academic hours• 5 a.h./week• 2 a.h. on Tue., 3 a.h. on Fri.
• Practicals: 64 a.h.• 4 a.h./week
Evaluation
• Participation in practicals: 5%
• Practical reports: 15%
• Weekly assessments & midterm exam: 20%
• Final examination: 60%
Recommended textbook
• Widmaier EP, Raff H, Strang KT (2006) Vander’s Human Physiology: The Mechanisms of Body Function, Tenth Edition. McGraw-Hill.
Course website
• University Course Center: • http://10.202.77.12/
• Course website:• http://10.202.77.12/JWCenterWeb/TemplateVi
ew?tempName=null&id=null&websiteId=26519&type=1&codeName=columnsun&courseWebsiteId=69995
Physiology: the study of the logic of life
Life
Logic
Study
生理学
Physiology
Plant Physiology
Bacterial Physiology
Viral Physiology
Animal Physiology
Human Physiology
……
Human Physiology
• Specific characteristics, functions and mechanisms of the human body that make it a living being
How ?What ?
Exercise Physiology
Aviation, high-altitude, and space physiology
Diving and Hyperbaric physiology
C. Galen (129-200)
(Ancient Greco-Roman)
History of Physiology
Leonardo da Vinci (1452-1519) (Italian)
De Motu Cordis
“On The Motion Of The Heart And Blood In Animals” (1628)
(http://www.fordham.edu/halsall/mod/1628harvey-blood.html)
W. Harvey (1578-1657) (English)
Rise of modern physiology
An Italian physiologist who
used a microscope to
discover the capillaries,
crowning Harvey’s
investigation
M. Malpighi (1628-1694)
L. Galvani (1737-1798) (Italian)
(1813-1878)
A French physiologist known
for his idea of the internal
environment
Павлов (Ivan Pavlov) (1849-1936)
A Russian physiologist known
chiefly for his development of
the concept of the conditioned
reflex
Awarded the Nobel Prize for
Physiology or Medicine in 1904
中国生理学会 Chinese
Association for
Physiological
Sciences
(founded in
1926)
林可胜 (Robert Kho Seng Lim) (1897-1969)“Father of Chinese Modern Physiology”
Levels of Physiological research
1. Cellular and molecular Physiology
Measurementof cell shortening
Ce
ll le
ng
th (m
)
120
905s
Measurement of [Ca2+]i
0.6
1.3
340
/380
5s
2. Organ and System Physiology
3. Integrative Physiology
Acute experiment
Chronic experiment
Body Fluid = 60% of Body Weight (BW)
Intracellular Fluid2/3, 40% of BW
Extracellular Fluid1/3, 20% of BW
Plasma 5% of BW
Interstitial Fluid15% of BW
70 kg Male, 42 L
Internal environment
External Environment
Extracellular Fluid1/3, 20% of BW
Plasma 5% of BW
Interstitial Fluid15% of BW
Internal Environment
Extracellular Fluid=Internal Environment
Homeostasis
Homeostasis (from the
Greek words for “same”
and “steady”):
maintenance of static or
constant conditions in
the internal environment
W. Cannon
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
----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
How is homeostasis achieved?
Regulation of body functions
• Nervous Regulation
• Humoral Regulation
• Autoregulation
Reflex
Knee jerk reflex
Nervous regulation
•Receptor
•Afferent (sensory) nerve
•Reflex center (brain or spinal cord)
•Efferent (motor) nerve
•Effector
Reflex Arc
Endocrine cells
Hormone
Hormone
Receptor
Traditional description of humoral regulation by hormone
Humoral regulation
•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
VasopressinOxytocin
Neuroendocrine
(Neurosecretion)
• Pheromone
Pheromone for MenOriginal price: $99.95
Ant Alarm Pheromone
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
Autoregulation
80~180 mmHg
Control systems of the body
CYBERNETICS
or Control and Communication
in the Animal and the Machine
(MIT Press 1948)
Norbert Wiener (1894-1964)Originator of Cybernetics
Open-loop system
Seldom seen under physiological conditions
Stress
1. Non-automatic Control System
Control Center EffectorsStimulus Response
Closed-loop system
Automatic control
Negative feedback
Positive feedback
2. Feedback Control System
Control Center EffectorsStimulus Response
Negative feedback: common
A change in a condition leads to responses from the
effectors which counteracts that change
Examples:
Regulation of blood pressure,
Regulation of body temperature,
Regulation of hormone release…
Gain of the negative feedback:
The degree of effectiveness with which a control
system maintains conditions
Correction
ErrorGain=
Positive feedback: uncommon
A change in a condition leads to responses from the
effectors which amplifies that change
+
Examples:
Child birth
Micturition
Blood coagulation
Vicious circle under pathophysiological conditions…
3. Feed-forward Control
Often seen in nervous system
Rapid
Adaptive control
Examples: some muscle contraction,
conditioned reflex
Control Center EffectorsStimulus Response
MonitorMonitorDisturbance
Summary
• Terms:
• Internal environment
• Homeostasis
• Negative feedback
• Positive feedback
• Regulation of body functions
THANK YOU FOR YOUR ATTENTION!