Kidney Homeostasis
by
Rosanna Parise and Marion Paxton
Background Information:
The kidney participates in whole-body homeostasis regulating acid-base balance, electrolyte
concentrations, extracellular fluid volume, and regulation of blood pressure. The kidney accomplishes
these homeostatic functions both independently and with other organs, particularly those of the
endocrine system. Various endocrine hormones help coordinate kidney homeostasis via feedback
mechanisms. The hormone involved in the feedback mechanism discussed in SB14U is antidiuretic
hormone (ADH).
As terrestrial animals, humans must balance the need to conserve water against the need to rid the
body of toxic metabolic wastes. The kidney must adjust both the volume and concentration of urine
depending on the animal’s intake of water and salt, and the production of urea. Osmoreceptor cells in
the hypothalamus monitor blood concentration. When blood concentration rises above the set point
of 300mosm/L, ADH is released into the blood from the posterior pituitary gland where it is stored.
ADH increases the permeability of the collecting tubule to water so more water can be reabsorbed.
This results in an increase in urine concentration and reduction in urine volume. When the
concentration of urine becomes too dilute, ADH release is suppressed and more urine is excreted.
The kidney’s function in homeostasis can be taught over the course of 5 lessons (some lessons may
take two periods depending on the length of your periods). The lessons will employ several different
teaching/learning strategies including the use of videos and visual aids, an article, a lab experiment, a
demonstration, a role-play exercise and a debate. These activities ensure that that multiple learning
styles are engaged.
Advanced Preparation:
Students should already have a good understanding of the human body systems especially the
nervous and endocrine systems including their function and how they interact. They should also
understand the different types of cell transport i.e. simple diffusion, osmosis, facilitated diffusion and
active transport prior to beginning lessons on the function of the kidney nephron in maintaining
homeostasis.
Special Materials:




dialysis tubing
iodine
coffee
sphygmomanometer
Specific Expectations
E1.1 assess on the basis of findings from a case study, the effects on the human body of taking
chemical substances to enhance performance or improve health (e.g. the risks and benefits of taking
large quantities of vitamins or amino acids; the effects on the human body of substances that people
use to cope with stress)
E2.2 plan and construct a model to illustrate the essential components of the homeostatic process
(e.g. create a flow chart that illustrates representative feedback mechanisms in living things)
E2.3 plan and conduct an investigation to study a feedback system (e.g., stimulus response loop)
E3.1 describe the anatomy and physiology of the endocrine, excretory, and nervous systems, and
explain how these systems interact to maintain homeostasis
E3.3 describe the homeostatic processes involved in maintaining water, ionic, thermal, and acid–base
equilibrium, and explain how these processes help body systems respond to both a change in
environment and the effects of medical treatments (e.g., the role of feedback mechanisms in water
balance or thermoregulation, how the buffering system of blood maintains the body’s pH balance,
the effect of medical treatments on the endocrine system, the effect of chemotherapy on
homeostasis)
Lesson Sequence:
Lesson
Introduction to the
Kidney: Structure
and Function
The Kidney Nephron:
Filtration and
Reabsorption
(NB: This may take 2
periods)
Teaching/Learning Strategies
 Complete the K and W of
a KWL chart as a class.
 Provide students with
basic urinary system
diagram – have them fill
in the name of
each structure as a group
activity.
 Students will then
complete a T chart on the
structure and function of
the following: kidney,
renal veins, renal arteries,
urinary bladder,
urethra
Resources
Youtube video on the
urinary system:
http://www.youtube.com
/watch?v=qxb2_d9ilEw

Youtube video of passive
transport demonstration:
http://www.youtube.com
/watch?v=2Th0PuORsWY

Teacher demonstration
on passive transport using
iodine and cornstarch
solution.
Students watch a Youtube
video on nephron
function. Ask students to
pay special attention to
the movement of
Assessment
Diagnostic KWL chart
Urinary system diagram:
http://www.ic.sunysb.edu
/Stu/sumusso/webquest_
files/image026.jpg
Youtube video on
nephron function:
http://www.youtube.com
/watch?v=glu0dzK4dbU

Nephron
worksheet



Homeostasis:
Feedback
Mechanisms




Homeostasis Lab:
The physiological
effects of caffeine
Kidney Disease
Article and Class
Debate
substances into and out
of the nephron. What is
filtered? What is not?
Students use the
interactive website to get
a deeper understanding
of nephron function.
Role-play exercise where
students are the filtrate
and classroom desks are
arranged as the nephron.
Students complete a
worksheet as homework
Quick review of the
nephron as a class using
the online quiz
Introduce hormone ADH
and ADH feedback loop
using a flowchart diagram
Have students read about
this feedback mechanism
in pairs (Pg 117 McGrawHill)
Students work in groups
to come up with a way to
demonstrate the ADH
feedback loop to their
peers
Students design and conduct
a lab investigation to observe
the effects of caffeine on
urine output
 Students use the
anticipation guide to read
the article as a group,
 Use the 4 corners strategy
to discuss/form opinions
about points presented in
the article
 Debate group formation
and debate preparation,
 Class debate (following
period)
 Peer and self assessment
 Complete L in KWL chart
Interactive Site:
http://www.biologymad.c
om/resources/kidney.swf
Worksheet:
http://www.biologycorne
r.com/anatomy/urinary/ki
dney_coloring.html
Quiz:
http://www.zerobio.com/
target_practice_quiz/targ
et_practice_quiz_kidney.
htm

Textbook
homework
questions

Lab report
Textbook homework
questions:
Pg 120 Q’s 4-6
Pg 134 Q’s 7, 12
Lab: Physiological effects
of coffee (see separate
post)
Article: “Bodybuilders see 
kidney damage with
steroids”

http://www.nytimes.com
/2009/12/10/sports/10st
eroids.html?_r=1&scp=2&
sq=steroids&st=cse
Class debate on kidney
transplant lesson plan:
http://www.triplescience.
org.uk/search/Resource30619.aspx
Anticipation
Guide
Peer and Self
assessment
Teaching Ideas:
Several instructional strategies can be used to teach the concept of kidney homeostasis. We suggest
introducing the topic by assessing what your students already know about kidneys and homeostasis.
This can be achieved using a KWL chart. The L section of the KWL chart should be completed on the
last day and can be used as a diagnostic before test preparation.
Using graphic organizers and diagrams such as the feedback loop and urinary system and nephron
diagrams will appeal to visual learners while using strategies that allow students to work in groups
such as the debate, will appeal to interpersonal and verbal learners. All students will benefit from the
open-ended inquiry style nature of the physiological effects of caffeine lab activity. You may have to
use guiding questions and approve procedures before allowing students to conduct this lab. It may be
best to assign the lab in the lesson prior so that students can brain storm ideas and hypotheses.
Students can monitor their urine output by keeping track of the frequency of their urination.
Kinesthetic learners will appreciate the opportunity to get out of their seats for the nephron role-play
activity. We suggest students wearing labels indicating what part of the filtrate they are e.g. water,
urea and Na+ . Some desks can be arranged as carrier proteins that need energy to pump Na+ into
and out of the kidney tubule. Also have students say aloud what is happening in each section of the
tubule as they pass through. Some students can also be ADH. They would be responsible for opening
the desks in the “collecting duct” to allow water to leave the nephron.
Reading an article about steroid use and kidney disease will make learning about kidneys relevant and
link science to society. Students can use an anticipation guide to read and understand the article. The
4 corners strategy can be used to initiate class discussion about the points presented in the article.
Statements such as “steroid use causes kidney disease” could be used to generate opinions and
discussion. Students can be placed in groups to prepare for a class debate the following period with a
resolution; “Body builders with kidney disease should be banned from receiving kidney transplants”.
Assessment:
Assessment for Learning:
 Kidney KWL chart
 Nephron online quiz
Assessment as Learning:
 Nephron function worksheet (K/U)
 ADH Feedback loop textbook questions (K/U)
 Group article anticipation guide (K/U, T/I)
Assessment of Learning:
 Lab report (T/I)
 Peer/Self evaluation (C, A)
Student Difficulties:
Student Difficulty
Students may have difficulty understanding
how and why different substances enter and
leave the kidney tubule.
Rectification




Some students may have trouble

understanding the feedback mechanism and
hormones involved in controlling urine output. 
Activate prior knowledge about how different
substances enter and leave the cell (cell transport:
simple diffusion, osmosis, facilitated diffusion,
active transport) prior to beginning the lesson on
the nephron.
Have students watch the Youtube video on the
function of the nephron and allow students to use
the interactive website to see where different
substances enter and leave the nephron.
Use the role-play exercise to help kinesthetic and
visual learners see when, where and why
different substances enter and leave the nephron.
Students can draw a diagram indicating where
water and sodium enter and leave the nephron
and where ADH acts to increase water
reabsorption.
Use a flow chart to help students visualize the
feedback mechanism.
Group weaker students with stronger students
during the problem solving activity.
Social Implications:

Effects of steroid use on kidney functioning

Effects of caffeine and alcohol on homeostasis

Kidney transplants and organ harvesting

Chronic renal disease (hemodialysis)
Annotated References and Resources:
Blake, Leesa. McGraw-Hill Ryerson Biology 12. Toronto: McGraw-Hill Ryerson, 2002.
This textbook contains 'The Physiological Effects of Coffee Lab'. It explains the kidney functions and
structure in detail, describes the role of ADH, and contains a weblink that talks about the process of
hemodialysis. This information can be accessed by visiting: www.mcgrawhill.ca/links/biology12
knight.noble-hs.sad60.k12.me.us/content/exploringLife/text/chapter32/concept32.2.html>
A great site to access background information on the kidney
http://www.youtube.com/watch?v=qxb2_d9ilEw
This video can be used as an introduction to the urinary system and shows an overview of the
structure and function of each organ.
http://www.ic.sunysb.edu/Stu/sumusso/webquest_files/image026.jpg
Diagram of the urinary system.
http://www.youtube.com/watch?v=2Th0PuORsWY
A video showing a passive transport demonstration involving dialysis tubing filled with cornstarch
solution being placed in a beaker containing iodine solution. We suggest that you recreate this
experiment and use it as a demonstration to refresh students’ memory of osmosis and diffusion prior
to the lesson on the function of the nephron.
http://www.youtube.com/watch?v=glu0dzK4dbU
This video shows how the kidney nephron functions in great detail.
http://www.biologymad.com/resources/kidney.swf
This is an interactive website that illustrates how different substances move through the kidney
nephron and how ADH affects the concentration of urine.
http://www.biologycorner.com/anatomy/urinary/kidney_coloring.html
This worksheet contains 2 very detailed diagrams of the kidney and nephron with detailed
instructions on how to colour the nephron to indicate the movement of blood and filtrate. It also
contains background information and questions for students to answer.
http://www.zerobio.com/target_practice_quiz/target_practice_quiz_kidney.htm
A quick and fun multiple choice kidney quiz that uses your responses to hit a target for points.
http://www.nytimes.com/2009/12/10/sports/10steroids.html?_r=1&scp=2&sq=steroids&st=cse
This is a New York Times article about the effects of steroid use on kidney functioning. It discusses a
case study where several body builders who used steroids were shown to have chronic kidney
disease.
http://www.cmaj.ca/content/175/5/489.full
Article “Kidney Transplants in Canada: unequal access”. This article highlights some of the kidney
transplants problems in Canada i.e. patients dying on waiting lists, transplants being ineffective if a
patient waits more than 2 years and organ donation rates by region.
http://www.triplescience.org.uk/search/Resource-30619.aspx
This website contains a free downloadable lesson plan for conducting a class debate on kidney
transplants. All references are British but the lesson plan can be easily modified for Canadian
students.