1. Introduction to MEDICAL PHYSIOLOGYBY
Dr. Arnold B. Fonollera, D.D.M.
Associate Professor
Biological Sciences Department

2. Medical Physiology defined
The study of the various systems of the body, from a molecular level through integrated functioning as it relates to the whole being.
Generally, the term medical physiology applies to human beings.
What is understood about cellular metabolism in any kind of plant or animal can be extrapolated to human physiology.
Therefore, the science of physiology applies to all living things.
Unlike branches of science focused on form and structure, such as anatomy, medical physiology is clearly concerned with function.

3. DR. Walter Bradford Canon 1871-1945
As a solo area of study, medical physiology stems from the work of the early 20th century physiologist, Walter Cannon, who presented his theory of homeostasis, or body wisdom.
Inspired by the earlier concept of milieu interieur, Cannon proposed homeostasis as a state of internal stability maintained by the body through deliberate communication and regulation between body systems.

4. The Basis of Medical Physiology
If one were to think of the human body as a home heating system, it makes perfect sense.
When a heating thermostat, which has been previously programmed, detects that the ambient temperature has fallen below an acceptable level, it sends an electronic signal to the furnace to produce more heat.
The human body is equipped with similar devices to trigger the appropriate response to maintain stability.
However, the systems of the body are not limited to electrical impulses and use chemical messengers as well.

5. The objective of this course is to help students learn and comprehend functions of the human body that are essential for clinical medicine.
Assist in acquiring a balanced foundation in cellular and systemic physiology in preparation for advanced study in other basic sciences and in clinical medicine.
Emphasis is on understanding general physiological principles and on how cellular and organ system functions are integrated within the organism.
In this regard, physiology may be distinguished from other basic biomedical sciences because it deals with the function of the whole organism and emphasizes those processes that regulate and control entire organ systems.
Course Objectives

6. A systems approach will be used in concentrating on each of the major organ systems individually.
Examine the interrelationships and interdependencies that exist among these various functional components.
Illustrate the relevance of knowledge to the practice of medicine.
A good working knowledge of physiology is a prerequisite for the student and practitioner who must ultimately interpret and evaluate disorders of function and provide rational treatment plans.

7. Physiology is Different Than Histology or Anatomy
Concepts vs Memorization
like physics there are things to memorize
but it is the concepts that are essential
you must put in the intellectual effort to understand the concepts
you must think about the ideas to become comfortable with them
do not expect that you will learn physiology by cramming for exams
Dynamic vs Static subject
new discoveries
new insights
so what you learn today may need to be revised in the future

8. What is Physiology?
Focuses on homeostasis, the maintenance of important properties of living
organisms in a narrow range in the face of significant environmental fluctuations
Examples of properties
blood pressure
ionic composition of blood
osmolarity of blood
oxygen and carbon dioxide content of blood
acid-base balance of blood
glucose concentration of blood
body temperature
Goals are to identify the processes that control and regulate the important
properties of living systems
sensors – afferent pathways
integrating centers - set points
effectors – efferent pathways

9. SENSE
How do these systems respond to perturbations in order to return to normal?
How does the body measure physiological parameters?
molecular mechanisms
cellular mechanisms
RESPOND

10. Steady State vs Equilibrium: The difference between Life and Death
equilibrium – no net change and no dissipation of energy
steady state – no net change but continuous dissipation of energy or matter
Life is a steady state process. We continuously dissipate energy to keep away from equilibrium.
steady state
rate of inflow
matches
rate of efflux
but flux through
the system
equilibrium
no net change

11. What is Physiology?
Focuses on homeostasis, the maintenance of important parameters in living organisms in a narrow range (in the steady state) in the face of significant environmental fluctuations
Example: body temperature
Sweat Ducts
elevated
Sweating
Core Body Temperature Sensors
CNS Integrating Center
normal
range
Skeletal Muscle, Brown Fat
Shivering
decreased

12. INFORMATION INTEGRATION Feedback control system
Components of a Physiological System
EFFECTORS
elevated
INFORMATION INTEGRATION
Feedback control system
SENSORS
normal
range
EFFECTORS
decreased

13. Example: Factors Effecting a Physiological Parameter
INTEGRATING CENTERS
SENSORS
stretch receptors
metabolic demands
DETERMINANTS
cardiac output
heart rate
stroke volume
contractility
FUNCTIONS
tissue perfusion
substrate delivery
waste removal
Blood Pressure
vascular capacity
arterial vs venous
elasticity of vascular wall
blood volume
distribution arterial vs venous

14. Physiology is the Basis of Medicine
many diseases cause organ dysfunction
medicine
tries to correct dysfunction
or minimize its effects
trying to restore system towards normal homeostatic setpoint
need to understand physiological parameters that can be manipulated
Example – Congestive Heart Failure (CHF)
leads to pump failure – inability to maintain adequate level of circulation
need to know causes of failure
some may be reversible others irreversible
if irreversible what else can be done to
maximize pumping
minimize symptoms
changes in blood volume, arterial or venous blood pressure
at molecular level need to know potential targets that can be modulated

15. Major Clinical Issues Related to the Course
What are the major determinants of blood pressure?
Why do people develop hypertension (HTN)?
How does knowledge of the physiology of blood pressure regulation guide options for the treatment of HTN?
What are the major determinants of cardiac output and heart function?
How do people in heart failure compensate for pump failure in order to maintain output?
How does a knowledge of cardiac physiology guide options for treatment of heart failure?
How does the kidney regulate composition and volume of body fluids?
How is acid-base balance maintained?
How does the respiratory system conduct and regulate gas exchange?

16. STUDY WELL!