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HMX Fundamentals

Build a body of knowledge on the systems that keep bodies functioning.

Understanding how the body works is vital for effectively treating patients.

In HMX Fundamentals Physiology, you’ll learn essential principles underlying how the human body functions, and see how this knowledge comes into play in real-world scenarios and in clinical settings from the intensive care unit to the cardiac catheterization lab.

Course Topics


  • Course introduction
  • Meet the faculty
  • High-level overview

Partial Pressure

  • Partial pressure basics
  • Partial pressures in the lungs and blood

Movement of Body Fluids

  • Osmotic forces
  • Starling forces
  • Body fluid compartments
  • Osmotic forces in the kidney

Flow Through Tubes

  • Ohm’s Law analogy
  • Resistance – series vs. parallel
  • Laminar vs. turbulent flow
  • Air trapping


  • Compliance basics
  • Surface tension
  • Laplace’s Law
  • Surface tension and alveoli
  • Elastic and surface forces in the lung

Supply and Demand

  • Aerobic vs. anaerobic metabolism
  • Oxygen delivery
  • Ohm’s Law application
  • Fick principle

Transmural Pressure

  • Transmural pressure basics
  • Flexible tubes
  • Cardiovascular applications
  • Respiratory applications

Dynamic and Steady State Conditions

  • Dynamic and steady state basics
  • Dynamic conditions
  • Pulmonary applications


  • Acid-base physiology
  • Respiratory acid
  • Metabolic acid
  • Metabolic acid – elimination by kidney


  • Homeostasis basics
  • Blood pressure
  • Acid-base applications

Exercise – Integration

  • Oxygen in exercise
  • Respiratory quotient
  • Anaerobic threshold
Download the Physiology course outline

Course Instructor

Richard Schwartzstein, Harvard Medical School

Richard M. Schwartzstein, MD

Ellen and Melvin Gordon Professor of Medicine and Medical Education, Harvard Medical School
Director of the Academy, Harvard Medical School
Director of the Center for Education, Beth Israel Deaconess Medical Center
Chief of the Division of Pulmonary and Critical Care Medicine, Beth Israel Deaconess Medical Center

Why do you think it’s important for aspiring health care professionals to learn physiology?

Physiology is truly the science of how the body works at a macro level. It helps us understand how all the organ systems are integrated and, when we are healthy, are seamlessly monitoring and responding to multiple unconscious inputs every moment of the day and night to keep us functioning well. It is also the foundation for studying and making sense of the impact of disease states, which invariably alter the normal physiology and lead to symptoms. The body’s response is invariably to activate counterbalancing physiological effects to try to restore function as close to normal as possible.

What do you want students to take away from this course?

Our philosophy with this course, as with most of my work with students, is to “teach what you can’t Google.” While there is important factual content in the course, my primary goal is to convey key concepts which provide a framework for how the body works and to help the learner gain an appreciation for the thinking process that doctors use to work through problems when the answer is not immediately apparent. In addition, I believe that curiosity is a keystone for being a good doctor, both humanistically and scientifically. I hope that the course will stimulate curiosity in those who tackle it and encourage them to continue their learning beyond the specifics of the course.

View a full list of HMX physiology faculty.

What Learners Say

Susan Sandford

Susan Sandford

New York University

“I actually wrote the professor to thank him for making [a subject] that could be really another language so easy to understand.”

Shareef Hussein

Shareef Mohammed Hussein

University of Baghdad Medical School

“I have learned how these concepts are applied in real clinical scenarios, how they can be presented in a patient, and how I can explain why these signs and symptoms are presented in this patient. I know why I would send a patient – for example with asthma, emphysema, or other respiratory diseases – for a pulmonary function test, and how I can interpret this test.”

Lena Levin

Medical device entrepreneur

“I liked specifically this ability for a person who’s not on a medical staff to be virtually in a clinical situation with real clinical patients. Especially I loved the way the physician talked to his patients; it’s not only the clinical knowledge but also how the physician approaches a patient of a certain age or with a certain disease.”

Read more learner profiles