1. Physiology
Dr. Anne Valle

2. Chapter 1 Objectives Introduction to basic concepts of physiology
Scientific Method
Levels of Organization
Homeostasis
- Feedback loops
Homework: Read Fox Chapter 1

3. Human Physiology
Physiology (physo = nature; logos = study): study of how the body works to maintain life
- cell  tissue  organ  organ system  organism
Pathophysiology: how physiological processes are altered in disease or injury

4. History of Physiology
Arist (384 – 322 BCE) – speculated on body function
Erasistratus (304 -~250 BCE) considered the father of physiology - applied physical laws to the study of human function
Galen ( A.D.) - believed the working body was not understandable without knowledge of its structure
William Harvey (1578–1657)-blood pumped in a closed system of vessels
Claude Bernard (1813 – 1878) – internal environment remains constant despite everchanging external environment
Walter Cannon (1871 – 1945) – coined the term ‘homeostasis’

5. Scientific Method
Discovery-based science - making observations and measurements regarding the natural world
Hypothesis-based science (aka the scientific method) -conduct and analyze experiments to test a hypothesis
1. develop a testable hypothesis to answer a scientific question based on natural observations
2. design and conduct experiments in an objective, unbiased, repeatable manner
3. analyze data and form conclusions that either support or deny the hypothesis

6. Discovery-based Science
Is there a difference in resting heart rate between people who exercise and those who don’t?
- Measure heart rate in people who exercise
- Measure heart rate in people who don’t exercise
- Analyze data and from conclusions
Study establishes a correlation (relationship) between exercise and heart rate but not causation

7. Hypothesis-based Science
Hypothesis - a tentative answer to a question
- an explanation on trial

8. Scientific Method Hypothesis-based science:
Form hypothesis: question to be answered
People who exercise regularly have lower resting heart rate
Treatment group: individuals subject to the test condition
Randomly choose a group who must exercise (experimental group)
Control group: similar individuals not subjected to treatment
Randomly choose a group that is not allowed to exercise (control)
Dependent variable: outcome you are measuring
Heart rate
Unbiased: double-blind (placebo) study
Random groups
Analyze data and form conclusions
“Controlled experiment” establishes causation

9. Scientific Method Introduce yourself to your neighbor
With your neighbor design a controlled experiment for the hypothesis that using echinacea speeds recovery from a cold
Treatment?
Control?
Dependent variable?
How would you avoid bias?

10. Scientific Method to Develop New Drugs
Biomedical research - test effectiveness & toxicity of a new drug
- first in vitro (tissue culture) then in vivo (animal models)
Clinical trials performed:
Phase I Trials: Toxicity and metabolism tested in healthy human volunteers (no toxic effects observed)
Phase II Trials: Effectiveness and toxicity tested in target population (effective with minimal toxicity)
Phase III Trials: Widespread test of drug in diverse population (gender, ethnicity, other health problems)
Phase IV Trials: Drug is tested for other potential uses (sent to FDA for approval)

11. Levels of Organization: Chemical and Molecular
Chemical or
Molecular Levels
Atoms in
combination
Complex protein
molecules
Protein filaments
Organ System Level
The heart
Cellular Level
Heart muscle cell
Tissue Level
Cardiac
muscle
tissue
Organ
Level
Cardiovascular
Reproductive
Urinary
Digestive
Respiratory
Lymphoid
Endocrine
Nervous
Muscular
Skeletal
Integumentary
Organism

12. Chemical and Molecular Level
Molecular composition
of the human body
Water
67%
Proteins
20%
Carbohydrates 3%
Lipids
10%
Elemental composition
Hydrogen
62%
Oxygen
26%
Carbon
Nitrogen
1.5%
Other Elements:
Calcium
Phosphorus
Potassium
Sodium
Sulfur
Chlorine
Magnesium
Iron
Iodine
Trace elements
0.2%
0.06%
0.05%
0.04%
0.03%
0.0005% %
(see caption)

13. Levels of Organization: Cellular
Chemical or
Molecular Levels
Atoms in
combination
Complex protein
molecules
Protein filaments
Organ System Level
The heart
Cellular Level
Heart muscle cell
Tissue Level
Cardiac
muscle
tissue
Organ
Level
Cardiovascular
Reproductive
Urinary
Digestive
Respiratory
Lymphoid
Endocrine
Nervous
Muscular
Skeletal
Integumentary
Organism

14. Levels of Organization: Cellular
Basic units of structure and function

15. Levels of Organization: Tissue
Chemical or
Molecular Levels
Atoms in
combination
Complex protein
molecules
Protein filaments
Organ System Level
The heart
Cellular Level
Heart muscle cell
Tissue Level
Cardiac
muscle
tissue
Organ
Level
Cardiovascular
Reproductive
Urinary
Digestive
Respiratory
Lymphoid
Endocrine
Nervous
Muscular
Skeletal
Integumentary
Organism

16. Levels of Organization: Tissue
_____tissue _____tissue _____tissue _____tissue
Cells with similar functions grouped into the 4 primary tissues

17. Levels of Organization: Organ
Chemical or
Molecular Levels
Atoms in
combination
Complex protein
molecules
Protein filaments
Organ System Level
The heart
Cellular Level
Heart muscle cell
Tissue Level
Cardiac
muscle
tissue
Organ
Level
Cardiovascular
Reproductive
Urinary
Digestive
Respiratory
Lymphoid
Endocrine
Nervous
Muscular
Skeletal
Integumentary
Organism

18. Levels of Organization: Organ
Anatomical and functional units made of two or more primary tissues

19. Skin—The Largest Organ
Outer layer of protective cornified epidermis
Next layer the dermis contains connective tissue, glands, blood vessels (BVs), nerves
Inner layer the hypodermis contains adipose tissue, BVs, nerves

20. Stem Cells
Most cells in organs are highly specialized or differentiated
Many organs retain small populations of adult stem cells
less differentiated so can become many cell types
Example: bone marrow stem cells can give rise to all of the different blood cell types

21. Body-Fluid Compartments
Our body has both intracellular and extracellular compartments:
Intracellular - inside cells (cytoplasm)
Extracellular - outside cells (blood plasma, interstitial fluid)
Compartments separated by the cell’s plasma membrane

22. Levels of Organization: Organ System
Chemical or
Molecular Levels
Atoms in
combination
Complex protein
molecules
Protein filaments
Organ System Level
The heart
Cellular Level
Heart muscle cell
Tissue Level
Cardiac
muscle
tissue
Organ
Level
Cardiovascular
Reproductive
Urinary
Digestive
Respiratory
Lymphoid
Endocrine
Nervous
Muscular
Skeletal
Integumentary
Organism

23. Levels of Organization: Organ System
Organ System Level
Cardiovascular
Reproductive
Urinary
Digestive
Respiratory
Lymphoid
Endocrine
Nervous
Muscular
Skeletal
Integumentary
Organism
Level
Organs located in different regions of the body that perform related functions are grouped into systems

24. Organismal Level Chemical level Atoms combine to form molecules.
Cellular level
Cells are made up
of molecules.
Tissue level
Tissues consist of
similar types of cells
Organ level
Organs are made up of
different types of tissues.
Organ system level
Organ systems consist of
different organs that work
together closely.
Organismal level
The human organism
is made up of many
organ systems.
Cardiovascular
system
Organelle
Molecule
Atoms
Smooth muscle cell
Smooth muscle tissue
Connective tissue
Blood vessel
(organ)
Heart
Blood
vessels
Epithelial
tissue 1 2 3 4 5 6

25. Homeostasis
Our organ systems work together to maintain homeostasis despite constant challenges

26. Homeostasis Maintenance of a state of dynamic constancy
internal conditions are stabilized above and below a physiological set point by negative feedback loops

27. Homeostasis and Negative Feedback Loops
All physiological parameters have a set point ‘X’
Sensor: Detects deviation from set point
Integrating center: Determines response
Effector: Produces response to re-establish X

28. Homeostasis
Negative feedback loops – body temperature, blood sugar, blood pressure
Example: control of body temperature
Set point: 37 °C
Sensor: Temperature receptors
Integrating center: Brain
Effector: sweat glands/muscles

29. Homeostasis: Negative Feedback
Example: control of blood sugar Set point: 5 mmol/L Sensor: pancreatic cells Integration: Endocrine system Effector: insulin and glucagon

30. Homeostasis: Negative Feedback
Example: control of blood pressure Set point: normal blood pressure Sensor: barorecptors Integration Center: brain Effector: heart / arteries

31. Homeostasis and Positive Feedback
Does not maintain homeostasis and is rare
Occurs when the body needs to amplify a process
Producing blood clots
Creates the LH surge that causes ovulation
Between the uterus and oxytocin secretion during childbirth

32. Homework Read Fox Chapter 2 Read the Skills Lab Note:
Come prepared to each lab session by reading the assigned lab
Always bring in your lab manual
1st day of lab bring in the required lab notebook
Lab notebooks will be kept in the lab