Section I subjects studied in
Concept of Physiology
Physiology belongs a branch of
What is Physiology?
Physiology is the science of studying
the functional activities and its
mechanisms in biological body. For
example: why can heart automatically
Physiology is also an
experiment science .Why?
the theories about the functional
activities are based on the experiments
British physiologist, William Harvey set
up the modern physiology. Observed
that blood flows in heart and vascular
In 1628,<<Heart and movement of
blood>> was published. It is the first
book of physiology based on
Field of Physiology
Each type of life has its own
Physiology can be divided into viral
physiology, bacterial physiology,
cellular physiology, plant physiology,
human physiology, and many more
Human physiology is the science of
studing the rule of physiological
functions in human body.
Animal experiments had become the
main way to study physiology, why?
Why must the medical students
study human physiology?
Medical science development is
closely related to physiology.
(1) The classical traditional chinese
much knowledge about
to guide the medical practice.
(2) Physiology provides the theories
to explain many diseases.
(3) Clinical practices test whether
the physiological theories are
correct or not and promote
development of physiology.
Investigation levels and
A) Investigation levels
(1) Cell and Molecular level
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.
Cell level research to understand the
function of the organ.
The physiological characteristics of
cells depend on the physical and
chemical features of the big chemical
molecules consisting of the cells.
molecular level research to study the
functions of cells. For instant:
Gene expression can also influence
the functions of cells.
Gene levels research
molecular biological methods for
molecular level and cell level research
Organ and system levels
The goals are to explore the effects
of organs and systems for human
body and how to performe their
activities, and the affecting factors.
For example: What is the function of
respiratory system? How are the
exchange of O2 and CO2? Which
factors can influence this exchange
Organ and System Physiology
The aims are to study interactions
among organs and systems, and
interaction between human body and
Human being has complicated
emotional activity and psychological
activity, these activities can affect
many somatic activity(
the relative behavior.
To develop integrative physiology
Experiment methods for
A Experiment in vitro(
a) experiment condition is easy to
b) To easily analyze the results
B Experiment in vivo(
Many conditioning reflex
experiments are chronic experiments.
a) To observe continuously the
activities in conscious condition;
b) The findings are similar to
The conditions in the body are so
complicated to analyze the results.
How to study human
Prepare the lesson before the new
Combine physiological theory with the
Perform the experiments yourself
and analyze the results with theories
you have learned.
Section II Internal environment
<1>Internal environment of
body fluid:(1)intracellular fluid 2/3
(2) extracellular fluid 1/3
(2)interstial fluid and fluid inside the
cavaties (greater periotoneal body
cavaty etc.) 3/4
In the extracellular fluid are ions and
nutrients needed by the cell. All cells
live in essentially the same
environment,the extracellular fluid
called the internal environment, a
term introduced more than 100 years
ago by French physiologist claude
used by physiologists to mean
maintenance of constant conditions in
the internal environment.
All of the organs and tissues perform
function to help maintain these
For instant: lungs provide oxygen
Kidneys maintain ions concentrations
U.S.A Physiologist Walter Canmon
make up the term, Homeostatis.
the various physiological arrangements
which serve to restore the normal state,
once it has been disturbed.
Including tow meaning:
(2)the control process maintaining the
constant conditions of internal
Section III Regulation
of Body Functions
Nervous regulation (
Reflex: the basic active manner of nervous
Reflex arc: including 5 parts: Receptor
Conditioning reflex and unconditioning
Conditioning reflex: set up after birth
Unconditioning reflex: set up before birth
Humoral regulation (
the hormones secreted by endocrine
glands act on the receptors of cells
(2)local chemical regulation: paracrine
Many endocrine glands are not
independent on nervous system, they
are regulated directly or indirectly
by nervous system, so the humoral
regulation is believed as one loop of
nervous system, i.e. nervous
Sympathetic nerve excites
noradrenaline secreted by medulla of
excitation in cardiac vascular system
> heart rate
and blood vessels
The regulation is not dependended on
nervous system or homoral regulation.
The cells or tissues themselves can
response to stimulus.
For instant: vascular smooth
muscles can contract when they are
stimulated by stretch stimuli.
Section IV Control systems of
To use cybernetics concept to analyze the
functional regulation in human body
automatic control system (
) belongs open loop system(
Feature: controlled system does not
affect the activities of control system.
For instant: depress reaction
) belongs a closed loop system(
automatic control (
Negative feedback: the more product
or result you have, the less you get.
For example: the arterial pressure
(2)Positive feedback: the more product
of result you have, the more you get.
For instance: childbirth, the
generation of nerve signals.