How does ADH increase facultative water reabsorption?
ADH
Nucleus
Filtrate inside of distal
tubule or collecting duct
regions of the nephrons.
Water
channel
Water
molecule
What is the effect of ADH (anti-diuretic hormone)
on water reabsorption & urine volume?
ADH: aquaporin channels are added to collecting tubule lumen surface.
No
ADH
Hyperosmotic
environment
ADH
H20 – passive; Na+ - active, Cl- - active
12/1/2016
Animation: &
http://cnx.org/contents/[email protected]:183/Anatomy-&-Physiology
2
Compare the reabsorption of
water, sodium & glucose
Glucose
Sodium
Water no ADH
Water + ADH
% of Total filtered that remains
100
90
Obligatory water
reabsorption: 80%
80
70
60
50
Facultative water
reabsorption: 0 to 19%
40
30
20
10
0
Capsule Prox tubule
12/1/2016
Loop
middle
Distal
tubule
Collecting Collecting
Duct start Duct end
3
Lecture 40: What is normal renal homeostasis?
What complications occur with chronic kidney disease?
• Renal Secretion
• pH Regulation
• Buffers
• Respiration
• Renal
• Overview of Renal Events
• Causes of CKD
• Using GFR as a predictor
• CKD  Metabolic Disorders
• Numerous organ systems
• Causes of major symptoms
• Renal Dialysis & Transplants
What needs to be in dialysis fluids?
https://psnet.ahrq.gov/webmm/case/224/dangerous-dialysis
12/3/15
Dr. Casey Self, Biol. 118, Autumn 2016
4
How are substances
secreted into nephrons?
Goals:
Remove more of
filtered substances
(H+, HCO3-)
Remove un-filtered
substances (drugs)
12/3/15
5
What are the normal homeostatic responses to excess acid?
1-2 minutes: increase
RR & tidal volume
Problem
1st buffers
limit pH shift
12/3/15
Chronic Acidosis can
inhibit CNS, muscles.
pH < 7.0 can be fatal.
1-2 hrs: increase renal
H+ secretion and
reabsorption of HCO36
What are the normal homeostatic responses to excess base?
1-2 minutes: decrease
RR & tidal volume
Problem
1st buffers
limit pH shift
12/3/15
Chronic Alkalosis can cause
muscle tetany, seizures
pH < 7.0 can be fatal.
1-2 hrs: increase
renal HCO3- secretion
& reabsorb H+
http://www.austincc.edu/apreview/EmphasisItems/Electrolytefluidbalance.html#renalmech
7
Overview: Filtration, Reabsorption & Secretion
12/1/2016
http://www.austincc.edu/apreview/PhysText/Renal.html
8
Why is Diabetes Mellitus the leading
cause of Chronic Kidney Disease (CKD)?
12/3/15
http://www.cdc.gov/diabetes/pubs/pdf/kidney_factsheet.pdf & http://www.niddk.nih.gov/health-information/healthtopics/kidney-disease/kidney-disease-of-diabetes/Pages/facts.aspx
9
How well do GFR &
albumins predict
cardiovascular
disease (CVD)?
Normal
eGFR = estimated glomerular filtration rate
The chances of dying or going on to
dialysis increase by 50-100% when
CVD and CKD are present together
12/3/15
Gansevoort, Correa-Rotter, Hemmelgarn,
et al. 2013; Silverberg et al. 2004
Normal
ACR = albumin-to-creatinine ratio
10
How are these organ systems affected by CKD?
12/3/15
Eckardt, Coresh,
Devuyst, et al. 2013
11
What are the major symptoms of CKD?
12/3/15
12
How do kidney transplants work?
In the News: As Drug Deaths Soar, a Silver Lining for Transplant Patients http://nyti.ms/2dzjIQ0
HLA – human leukocyte antigen
MHC – major histocompatibility complex
Number of HLA mismatches (MM) impacts
transplant survival
12/3/15
https://bethematch.org/for-patients-and-families/finding-a-donor/hla-matching/
13
What are the benefits & risks of a kidney transplant?
Is a kidney transplant a
permanent cure?
What are the risks
to a living donor?
What can you do to
prevent organ
rejection?
Why is the new kidney put
so low in the abdominal
cavity?
http://www.kidneypatientguide.org.uk/site/TRAanim.php
12/3/15
14
Topics to understand & review:
1. Explain the process of renal tubule secretion. What types of substances are
removed from plasma this way? Are only non-filtered substances removed by
secretion? Why is tubular secretion a “rate-limited” process?
2. How quickly do each of these respond to pH imbalances: buffers, respiratory &
urinary system? Explain how each organ system responds to a decrease in pH
compared to an increase in pH. Why is pH regulation a negative feedback process?
Why is urine pH = 5.5-8.0, when blood plasma is 7.35-7.45 normally?
3. Compare the major causes of chronic renal failure. Why is Diabetes the leading
cause of kidney failure within the U.S.? How can atherosclerosis & the reninangiotensin pathway lead to a decrease in blood flow to your kidneys?
4. Graph & predict the change in plasma urea on the Y-axis, as the % of nephrons lost,
increases on the X-axis. How are the number of nephrons correlated to the body’s
glomerular filtration rate?
5. How similar are Asian Americans, African Americans & whites in their hazard ratios,
using GFR in predicting end stage renal disease? Is GFR a good predictor?
6. Explain the causes & complications from these symptoms of chronic kidney failure:
uremia, acidosis, anemia, hypertension, edema, acidosis, & hypocalcemia.
7. Explain how dialysis works. Why is fluid balance so important to kidney failure
patients?
12/3/15
15
Additional Resources
1.
Centers for Disease Control and Prevention. (2015) Chronic Kidney Disease Surveillance System—United States.
http://www.cdc.gov/ckd
1.
Arora P, Batuman V. (2015) Chronic Kidney Disease. http://emedicine.medscape.com/article/238798-overview
2.
Dwivedi RS, et al. (2011) Beyond genetics: epigenetic code in chronic kidney disease. Kidney Int. 79(1):23-32.
3.
Eckardt K-U, Coresh J, Devuyst O, et al. (2013) Global Kidney Disease 1: Evolving importance of kidney disease: from
subspecialty to global health burden. Lancet 382:158–169
4.
Gansevoort RT, Correa-Rotter R, Hemmelgarn BR, et al. (2013) Global Kidney Disease 3: Chronic kidney disease and
cardiovascular risk: epidemiology, mechanisms, and prevention. Lancet 382:339–352.
5.
NIDDK (2015) Kidney Disease Statistics for the United States. http://www.niddk.nih.gov/health-information/healthstatistics/Pages/kidney-disease-statistics-united-states.aspx
6.
Venkatachalam MA,. Griffin KA, Lan R, et al. (2010) Acute kidney injury: a springboard for progression in chronic kidney
disease. Am J Physiol - Renal Physiol. 298(5):F1078-F1094. http://ajprenal.physiology.org/content/298/5/F1078
7.
Wen CP, Matsushita K, Coresh J, et al. (2014) Relative risks of chronic kidney disease for mortality and end-stage renal
disease across races are similar. Kidney International 86:819–827.
8.
Zalyapin EA, Bouley R, Hasler U, et al. (2008) Effects of the renal medullary pH and ionic environment on vasopressin
binding and signaling. Kidney International 74:1557–1567.
9.
Animations
a) Dialysis: http://www.kidneypatientguide.org.uk/HDanim.php
b) Dialysis: http://www.biotopics.co.uk/human2/andial.html
12/3/15c) Fluid balance: http://www.kidneypatientguide.org.uk/fluidAnim.php
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