Physiology 3

1. Physiology 3 Dr. Anne Valle Office: SCI-265 Email: valle_anne@smc.edu

2. Chapter 1 ObjectivesIntroduction 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 (130 -201 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 Organism Level Organ System Level Cardiovascular Endocrine Lymphoid Nervous Respiratory Digestive Muscular Skeletal Urinary Integumentary Reproductive The heart Organ Level Cardiac muscle tissue Atoms in combination Tissue Level Heart muscle cell Complex protein molecules Protein filaments Cellular Level Chemical or Molecular Levels

12. Other Elements: Calcium Phosphorus Potassium Sodium Sulfur Chlorine Magnesium Iron Iodine Trace elements 0.2% 0.2% 0.06% 0.06% 0.05% 0.04% 0.03% 0.0005% 0.0000003% (see caption) Water 67% Oxygen 26% Hydrogen 62% Proteins 20% Carbon 10% Lipids 10% Carbohydrates 3% Nitrogen 1.5% Molecular composition of the human body Elemental composition of the human body Chemical and Molecular Level

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

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

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

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

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

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

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

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

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