Clinical Kidney Physiology with Alan Segal, MD MSEE and Craig Hurwitz, MD (at The Hurwitz Lab)

Dr. Hurwitz invited his nephrology mentor Alan Segal, MD MSEE to review a series of challenging kidney physiology topics at The Hurwitz Lab located at NNH. Alan has a unique way of explaining very difficult topics making it easy to understand and often provides a unique insight from his engineering background. There is over 20 hours of content in this series of discussions. These lectures are perfect for the medical student, resident or fellow who wants to get that deep understanding of the most challenging physiology topics. Enjoy these long form videos by "2 Kidney Guys in the FLOW state" - PODCASTS with Craig & Alan.

On Salt & Water

In this episode I speak with my nephrology mentor Dr. Alan Segal.  We focused this discussion on the topic of TONICITY disorders and understanding the physiology of water homeostasis in health and disease.  If you've been confused by "hyponatremia" then you will really enjoy this discussion.  Alan also presents his 2021 ASN poster (hot off the press)  on a non-linear correction for [Na] in the setting of hyperglycemia.  Enjoy!!


In this episode I have Dr. Alan Segal back to teach (and excite) us about the topic of Acid-Base balance.   This topic can be one of the most daunting but Alan guides us through all of the disorders and an sensible approach to diagnosing them.  Enjoy the "emia's" and "oses" of Acid-Base balance.


In this episode Alan is back to complete our physiology TRIFECTA by discussing potassium.  While talking about water and protons was a total blast on our previous podcasts, Potassium is really Alan's wheelhouse. I really enjoyed this podcast and although I've worked on potassium channels in Alan's lab and I've been in clinical nephrology practice for 20 years now I still walked away with new lessons that will impact how I practice medicine.  If you love potassium you will love this podcast!! Enjoy (don't forget to like and subscribe to THL)


In this episode Alan and I discuss Flow.  We are all so caught up with PRESSURE (or driving force) that we miss the important fact that life is all about FLOW.  Alan does a great job helping understand the relationship of flow and driving force and how it applies to the kidney.  At the end he presents his novel electrical model of the Glomerulus to help us understand the regulation of glomerular hemodynamics in health and disease.

Acute Kidney Injury

Acute kidney Injury is the most common reason I get called for a "kidney consult" at the hospital.  Most commonly it's secondary to a severe illness like sepsis, kidney toxic exposures (nephrotoxins) or ischemia (low FLOW to the kidney).  It's a syndrome that has many causes and Alan does an amazing job walking us through the topic of AKI by presenting actual cases he has seen over the years.  He talks about biomarkers (or lack of), risk factors, prognosis and more.   Don't miss this clinically relevant review!

Countercurrent Exchange

You've reviewed the chapters and watched the videos but still don't quite get CounterCurrent Multiplication do you!!  I've been where you are!  This is one of the more challenging topics on how the AMAZING KIDNEY creates a huge osmotic gradient needed to keep us from dying of dehydration.  In this video Alan and I discuss and review the current understanding of countercurrent multiplication and make it tangible.  Now I know you can do this... let's go!

Salt Transport Along the Nephron

This video is an epic tour of the nephron with a comprehensive review of salt transport.  Alan will discuss each segment of the nephron with respect to the epithelial transport features along with a review of physio-pharmaco-genetics. Alan is an expert in the field of ion channels and epithelial transport and this review is like no other I've seen. If you want to understand salt balance, how diuretics work, tubulopathies (inherited and acquired) and of course blood pressure then this is the talk for you!  Don't forget to like and subscribe to our channel!


Interested in Hypertension?  From ancient China through Guytonian theory all the way to the most up-to-date societal guidelines this video leaves no stone unturned.  We discuss history, philosophy (Plato's Allegory of the cave), physiology, medical management and future directions in Hypertension.  This is probably the most comprehensive hypertension review you will find - just turn the cameras on and let Alan do his thing! Brace yourself!!

Disordered Mineral Metabolism & Aging

For years we've known that kidney disease sets into motion rapid ageing and a very high risk for cardiovascular disease.  Disordered mineral metabolism is at the center and in recent years the fields of phosphorus dysregulation and ageing have collided as we've learned about FGF23 and Klotho.  In this video Alan and I discuss our current understanding of this newer FGF-Klotho endocrine system and it's impact on renal disease, cardiovascular disease and ageing.  Don't miss this video if you want to live long and prosper!

Diabetes Insipidus

After watching our videos on Salt and Water and also Sodium Transport Along the Nephron you now have all the requisite tools to join us for a detailed look at Diabetes Insipidus.  Armed with the control system model Alan does a fantastic job outlining the interplay between thirst, AVP, the AVP2 Receptor and Aquaporin 2. If you ever wanted to understand disorders leading to hypertonicity then this is the video for you!

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