Transcript Introduction

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
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Physiology: the study of the
logic of life
生
理
学
Life
Logic
Study
Viral
Physiology
……
Bacterial
Physiology
Physiology
Human
Physiology
Animal
Physiology
Plant
Physiology
Human Physiology
• Specific characteristics,
functions and mechanisms
of the human body that
make it a living being
What ?
How ?
Exercise Physiology
Aviation, high-altitude, and space physiology
Diving and Hyperbaric physiology
History of Physiology
C. Galen (129-200)
(Ancient Greco-Roman)
Leonardo da Vinci (1452-1519) (Italian)
Rise of modern physiology
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)
An Italian physiologist who
used a microscope to
discover the capillaries,
crowning Harvey’s
investigation
M. Malpighi (1628-1694)
L. Galvani (1737-1798) (Italian)
A French physiologist known
for his idea of the internal
environment
(1813-1878)
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
Павлов (Ivan Pavlov)
(1849-1936)
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
Cell length (m)
1. Cellular and molecular Physiology
120
340/380
1.3
90
5s
Measurement
of cell shortening
0.6
Measurement of [Ca2+]i
5s
2. Organ and System Physiology
3. Integrative Physiology
Acute experiment
Chronic experiment
Internal environment
Body Fluid = 60% of Body Weight (BW)
Plasma 5% of BW
Extracellular Fluid
1/3, 20% of BW
Interstitial Fluid
15% of BW
70 kg Male, 42 L
Intracellular Fluid
2/3, 40% of BW
Plasma 5% of BW
Extracellular Fluid
1/3, 20% of BW
Interstitial Fluid
15% of BW
Internal Environment
External 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
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
Regulation of body functions
• Nervous Regulation
• Humoral Regulation
• Autoregulation
Nervous regulation
Reflex
Knee jerk reflex
Reflex Arc
•Receptor
•Afferent (sensory) nerve
•Reflex center (brain or spinal cord)
•Efferent (motor) nerve
•Effector
Humoral regulation
Hormone
Traditional description of humoral
regulation by hormone
Endocrine
cells
Receptor
Hormone
•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
Neuroendocrine
(Neurosecretion)
Vasopressin
Oxytocin
• Pheromone
Ant Alarm Pheromone
Pheromone for Men
Original price: $99.95
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
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
1. Non-automatic Control System
Open-loop system
Seldom seen under physiological conditions
Stress
Stimulus
Control Center
Effectors
Response
2. Feedback Control System
Stimulus
Control Center
Closed-loop system
Automatic control
Negative feedback
Positive feedback
Effectors
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
Gain=
Correction
Error
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
Monitor
Stimulus
Control Center
Disturbance
Effectors
Response
Summary
• Terms:
• Internal environment
• Homeostasis
• Negative feedback
• Positive feedback
• Regulation of body functions
THANK YOU FOR YOUR
ATTENTION!