Physiology Introduction I
What is physiology?
The study of how living organisms "work", or function of
The study of biological functions.
1. Organism- Human phys, plant phys, comparative phys, bacterial phys
2. Organ systems- EX: cardiovascular, Renal
3. Condition- Pathophysiology
What is Pathophysiology?
aka pathologic physiology
Part of the "Condition" type of physiology
It is an altered state due to disease
"Physiology gone wrong"
Ancient Greeks, Egyptians, and Chinese treated endocrine related problems
1. Aristotle 4. Claude Bernard
2.Erasistratus 5. Walter Canon
384 BC-322 BC
The Humors of Life:
Blood- sanguine (healthy), Yellow bile- Choleric, Black bile- Melancholic, Phlegm- Phlegmatic
384 BC- 250
"Father" of Physiology
Attempted to apply physical laws to study human function
Traced sensory and motor nerves to brain, veins, and arteries to
EX: believed nerves carried a "nervous spirit" from the brain and that arteries carried "animal sprits"
Introduced experimentation to study function
The "Father" of MODERN Physiology
Milieu interieur- an internal "mixture" that remains
constant, despite changes in the external environment
EX: If you jump in the ocean, which is salty, your internal "mixture" will not become salty
Created the term "homeostasis" which means " staying
It is never perfectly constant
Wrote the book , "Wisdom of the Body"
Nobel Prize in Physiology/ Medicine
1. Sir Fredrick Grant Banting and John James Richard Macleod-
Discovery of Insulin
2. Earl W. JR. Sutherland- 1971
Studied hormone action in cells
Discovered the role of cyclic Adenosine Monophosphate (cAMP) in cellular translation of hormonal signal (the first 2nd messenger discovered)
Recent Nobel Awards
1. Robert G. Edwards
2. James E. Rothman, Randy W. Sheckman, and Thomas C. Sudhof
3. John O'Keefe, May- Britt Moser, and Edvard I. Moser
4. Yoshinori Ohsumi
Robert G. Edwards
Development of inVitro fertilization
James E. Rothman, Randy W. Sheckman, and Thomas C. Sudhof
How the body's cells decide when and where to deliver molecules
John O'Keefe, May-Britt Moser, and Edvard I. Moser
Discoveries of cells that constitute the brain positioning system
Called "grid cells"
Nerve cells in hippocampus
Mechanisms of autophagy
Autophagy- eating yourself
Contributed to embryo development and cell differentiation
Cells use it to damage proteins and invading organisms
Disrupted autophagy is linked to Parkinson's, Type 2 diabetes, Alzheimer's, and cancer
1. Observe Nature
2. Pose a hypothesis
3. Test hypothesis. Experiment. (must be testable)
4. Collect data. Analyze statistically (must use statistics because things happen by chance
5. Hypothesis supported by data? Accept.
6. Reformulate Hypothesis. Re-test.
Receives treatment under consideration.
An experimental group with NO TREATMENT.
Subjects are not certain if receiving active or inactive agent
Placebo- an Inactive agent
Double Blind Study
Experimenters AND subjects are uncertain who receives the active agent.
Subjects act as control AND experimental subjects.
Fluid IN cells
2/3 of the body's intracellular fluid is water (28 Liters)
Fluid OUTSIDE of the cells
1/3 of the body's extracellular fluid is water (14 Liters)
14 Liters is broken up into
1. 3 liters of PLASMA
2. 13 liters of INTERSTITIAL FLUID
How do we preserve life?
Life can be preserved by keeping the internal environment relatively stable
Maintaining a state of dynamic constancy, or a process which maintains internal stability
Impact of Homeostasis,
Compensation for disturbances allows internal stability and organism lives
History of Homeostasis
Claude Bernard- Milieu interieur= beginning stages of the realization of homeostasis (stable internal environment)
Walter Canon- created the term "homeostasis"
3. Control Systems
Involves simple or complex organ systems
Correction for disturbances
Is when a physical or biochemical entity is adjusted
EX: Blood glucose, blood pressure
USES control systems
Is integrated components regulating a parameter
Organisms prevent significant changes in parameters via control systems
Control Systems Components
1. Input Signal
2. Integrating Center
3. Output Signal
Parameter and its detector
EX: In fish tank, a signal passes from the sensor to the control box through the wire (control of temp)
Integrating Center (aka Controller)
Needs to measure and know where the parameter is
Judges if the levels are adequate or not
EX: In fish tank, the control box. It is programmed to respond to temp below 29 degrees
Most systems are output signals
EX: In fish tank, the signal passes through the wire to the heater
EX: In fish tank, the response is that the water temp increases to keep fish alive/ at homeostasis
A process where the output signal returns to alter the system
1. Negative Feedback
2. Positive Feedback
The system returns the parameter towards a set point- common
NEGATES the disturbance
Brings back to homeostasis
EX: Brings temp up or down
The system moves parameter away from a set point- rare
makes it worse
EX: In birth/pregnancy- Oxytocin, a pituitary hormone involved in birth
Is NOT homeostatic- because it never keeps you at a balance