Kidney Homeostasis

Vega Lee and Apolonia Kukla

SBI 4U

The Need to Maintain Homeostasis!Each cell is a sophisticated machine, finely tuned to carry out a precise role within the body! When does this specialization occur, you ask? Only within narrow limits of temperature, pH, concentrations of glucose and oxygen and many other factors that must be held relatively constant for cells to function properly. Homeostasis, then, can be defined as the dynamic constancy of the internal environment.

for life!

An elephant regulating body temperature by spraying water on

himself.

This is im

ortantp

Lesson 1: Kidney Structure and FunctionIntroduce anatomy and physiology of the kidney and excretory system.

Lesson 2: Introduction to HomeostasisIntroduce the concept of homeostasis

Lesson 3-4: Excretory SystemDescribe the other components of the excretory system and how they all interact.

Lesson 5: Kidney Dissection LabDiscover the anatomy of the kidney through dissection.

Lesson Sequence

Lesson 6: Feedback System (Stimulus response loop)

Discuss the concept of a feedback system and a response loop.

Lesson 7: Control MechanismsDiscuss the different control mechanisms that the body uses to regulate water in the body.

Lesson 8: Effects on Excretory System Investigate how different substances and/or environment affect the excretory system when subject to various chemicals and/or stimuli.

Lesson 9-10: Culminating TaskLab investigation observing the responses that an invertebrate may have to different stimuli.

Lesson Sequence continued

Curriculum 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 E1.2 evaluate, on the basis of research, some of the human health issues that arise from the impact of human activities on the environment E2.1 use appropriate terminology related to homeostasis, including, but not limited to: insulin, testosterone, estrogen, nephron, dialysis, pituitary, synapse, and acetylcholine E2.2 plan and construct a model to illustrate the essential components of the homeostatic process E2.3 plan and conduct an investigation to study a feedback system E2.4 plan and conduct an investigation to study the response mechanism of an invertebrate to external stimuli E3.1 describe the anatomy and physiology of the endocrine, excretory, and nervous systems, and explain how these systems interact to maintain homeostasisE3.3 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

Kidney Structure and FunctionKidney Homeostasis

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The Mammalian KidneyIn humans, the kidneys are fist-sized organs located in the region of the lower back. Each kidney receives blood from a renal artery, and it is from this blood that urine is produced. Urine drains from each kidney through a ureter, which carries the urine to a urinary bladder. Within the kidney, the mouth of the ureter flares open to form a funnel-like structure, the renal pelvis. The renal pelvis, in turn, has cup-shaped extensions that receive urine from the renal tissue. This tissue is divided into an outer renal cortex and inner renal medulla. Together, these structures perform filtration, reabsorption, secretion, and excretion.

The nephron tubule is surrounded by peritubular capillaries, which carry away molecules and ions that are reabsorbed from

the filtrate.

Nephrons

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The Kidney and

Nephron: OverviewVideo at the following link:

http://www.khanacademy.org/science/biology/v/the-ki

dney-and-nephron?playlist=

Biology

The kidneys have four main functions. Molecules enter the urine by filtration out of the glomerulus and by secretion into the tubules from surrounding peritubular capillaries. Molecules that entered the filtrate can be returned to the blood by reabsorption from

the tubules into surrounding peritubular capillaries, or they may be eliminated from the body by excretion through the tubule to a ureter, then to the bladder.

Functions of the Kidneys

Lesson Strategy

Students will create a hand-made wordle for homeostasis (this will give me an idea of what they already know).

Lecture using either the video or textbook to go through structure and function of kidney

Mini-challenge: Create a story starting with I am a kidney named … (should include some structures and functions talked about in class).

Assessment

Diagnostic Assessment of the wordle, what they may already know.

Mini-challenge, a diagnostic assessment to see what they have learned.

Teaching Approaches

Homeostasis Lesson

Provides an overview on homeostasis and body balance using videos, examples, and charts etc.

http://www.lionden.com/homeostasis.htm

Also Easy Study Canada has made a study guide for students to review homeostasis.

http://easystudy.ca/?p=2132

Homeostasis Gizmo

Adjust the levels of clothing, perspiration, and exercise to maintain a stable internal temperature as the external temperature changes.

http://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=519

Homeostasis

Lesson Strategy

Intro to homeostasis (the basics using lecture or slides etc.)

Gizmo: Human Homeostasis, fill out worksheet that goes with it.

Mini challenge: definition of homeostasis in your own words

Assessment

Quiz: kidney structure/function

Gizmo worksheet completion, diagnostic to see if they understood the gizmo

Mini-challenge: to see if they understand the concept to make their own definition (diagnostic)

Teaching Approaches

Overview Slideshow

This slideshow goes through everything from excretion and homeostasis to the functions of the kidneys etc.

http://www.slideshare.net/Sianfergs/the-human-excretory-system-10220059

YouTube Video

This is a cool commoncraft youtube video explaining the excretory system in detail, students can make one of their own as an assignment.

http://www.youtube.com/watch?v=47OKHDqu2Hc

Excretory System

Lesson Strategy

This was divided into two lessons so the first one we would start out with a mini challenge: who can remember the most components of the excretory system.

Lecture/slideshow presentation with the information.

Take home assignment: create a study guide for the lecture/info from todays lesson

Assessment

Quiz: Homeostasis

Study guide assignment, diagnostic to see where they are with the material

Teaching Approaches

Lesson Strategy

The lesson after will start with the study guide check.

Mini challenge: name the steps for removing waste from the body

Get into groups to create a commoncraft presentation, which they will be given an example from the youtube video mentioned on slide 14.

They have until the end of class. Present next class.

Assessment

Study guide check, diagnostic

Commoncraft presentation with rubric

Mini challenge, diagnostic

Teaching Approaches continued

Kidney Dissection Lab

Pdf document link:

file://localhost/Users/ApoloniaKukla/Desk

top/Homeostasis PPT/kidney_dissection_

mini_lab.pdf

Safety Considerations for the LabYour lab tools should be cleaned, dried and returned at the end of the class.Your group is solely responsible for your scalpel. Show your equipment to the teacher before returning it.Always wash your hands with soap and your work area when you are finished. Handle dissecting tools carefully (don’t cut directly towards yourself or your lab partner(s)). You should wear gloves and safety goggles. Lab aprons are available if you choose to use them.

Lesson Strategy

They will be given the kidney dissection package to complete the lab during this class, the package is located on slide 17.

Mini-challenge: name one part of the kidney you labeled today and it’s function

Assessment

Lab report due next lesson (basically hand in package), assessment criteria is at the end of the package.

Mini challenge, diagnostic

Teaching Approaches

Negative Feedback Loops

Perturbing factorStimulus:

Deviation from set point

Sensor: Constantly monitors

conditions

Integrating centre:

Compares conditions to set

point

Effector: Causes changes to

compensate for deviation

Response: Return to set point

Negative feedback loops maintain a state of

homeostasis, or dynamic constancy of the internal

environment, by correcting deviations from a set point.

Negative feedback

loop completed

Negative Feedback loops

continuedNegative feedback loops keep the body temperature within a normal range. An increase or decrease in

body temperature is sensed by the brain. The integrating centre in the

brain then processes the information and activates

effectors, such as surface blood vessels, sweat glands, and skeletal

muscles. When the body temperature returns to normal,

negative feedback prevents further stimulation of the effectors

by the integrating centre.

Positive Feedback Loops

An example of positive feedback during childbirth. This is one of the few examples of

positive feedback that operate in the vertebrate body.

Tutorial plus Animation

This tutorial is pretty nifty, it shows an animation along with the explanations of control, regulation and feedback in homeostasis.

http://bcs.whfreeman.com/thelifewire/content/chp41/41020.html

YouTube Video

This video gives a super thorough explanation of negative versus positive feedback with real life examples. Courtesy of Mr. Anderson.

http://www.youtube.com/watch?v=CLv3SkF_Eag&feature=related

Feedback System

Lesson Strategy

Start the class with this Seinfeld clip and get the students to explain where homeostasis comes in. http://www.youtube.com/watch?v=lt6KRKHpKhY

After this have a short lecture with the above diagrams can include and animation if you like and then ask the students to create their own flow-chart for a negative feedback loop

Mini-challenge: give me an example not to do with bio that uses negative feedback

Assessment

Quiz: Excretory system

Seinfeld clip discussion participation

Mini-challenge, application of information learned

Teaching Approaches

Antidiuretic hormone stimulates the reabsorption of water by the kidneys. This action completes a negative feedback loop and helps to maintain homeostasis of blood volume

and osmolality.

A great animation for this particular example can also be found at the following link: https://sites.google.com/site/virtuallabsrenal/anatomy/adh-secretion

Control Mechanisms

A lowering of blood volume activates the renin-angiotensin-aldosterone system.

A great handwritten tutorial can be found at the following link: http://www.youtube.com/watch?feature=fvwrel&NR=1&v=PDE2qdS2ZvY

Control Mechanisms

Lesson Strategy

Mini-challenge: name the four main functions of the kidney.

From there we will work through control mechanisms, the use of the animation on slide 24 and 25, along with the textbook.

The students must create a summary chart of control mechanisms, where they occur, the function, the substances that are transported are some examples for title headings. (can be done in groups, to then do a jigsaw)

Assessment

Quiz: feedback system

Mini-challenge, diagnostic

Summary flow-chart for jigsaw, completion and understanding (experts on the material)

Teaching Approaches

Effects on Excretory System

Certain drugs can have an effect on the excretory system for example alcohol, illegal drugs, steroids, and even something as simple as caffeine. We will go over common effects of diuretics, their purpose being to remove excess water from the body although each type of diuretic does this in a different way.Most common side-effects include: dehydration, hypotension, muscle cramps, electrolyte disturbances, muscle weakness, seizures, gout, fatigue.

Lesson Strategy

Start out with a what you know activity, there will be headers on the board (alcohol, prescription drugs, steroids and caffeine), the students will be given sheets of paper with how they may harm r help, they need to stick the sheet under the appropriate heading.

Then we will get into a discussion and look at the drug dosage gizmo at this link: http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=525 , along with a worksheet

Mini-challenge: name something you learned today about one of the four categories on the board

Assessment

Quiz: control mechanisms

Diagnostic assessment the on board activity

Gizmo worksheet completion

Mini-challenge, diagnostic

Teaching Approaches

Differentiated Assessment: Culminating Task

Students can choose two of the following options for their culminating task assessment on homeostasis:

A poster displaying the kidney structure (Visual)

A song about the concept of a feedback loop (Musical)

A 3-D model showing the kidney structure (Kinesthetic)

A videotaped oral or hand-written story about the process of kidney homeostasis (Linguistic)

A journal entry on what they learned about homeostasis (Intrapersonal)

A lesson on protein synthesis that is taught to the class (Interpersonal)

A lab activity involving the response of an invertebrate to external stimuli (Logical)

Differentiated Assessment continuedStudents can choose two of the following options for their culminating

task assessment on homeostasis:A homeostasis case study to analyze (Logical)

A patient description of health will be given, the student must determine the patients illness as well as giving solutions to help the problem (either present orally or in a report) (Logical/Linguistic)

A Bill-Nye episode on homeostasis (can be a play or videotaped) (Linguistic/Kinesthetic)

A debate on some of the bad stimuli on homeostasis (example drugs, alcohol, etc.) Must choose a group of four and each person will be given a different perspective to present their arguments from (Interpersonal)

Concept map of homeostasis (Visual)

Safety Considerations for the LabFor the invertebrate lab some things to consider are ethical standards when dealing with live substances. The invertebrate is a living being, therefore after the lab make sure to either put it back in the wild or in a safe place where it can still survive. If any students are allergic to certain invertebrates please either avoid being involved in the lab or have a partner who is not. Make sure to wear gloves and goggles and any other precautions necessary for the lab.

Differentiated Assessment continuedStudents understanding of kidney homeostasis will also be evaluated through the final unit testAs well, students will be evaluated throughout the unit by formative assessments including quizzes, the lab assignment and the commoncraft presentation of the excretory system. Through diagnostic assessments of their progress, the mini-challenges and homework completion.Also, observations of participation and the learning skills throughout the unit.

1. Homeostasis means stable

Sometimes the students may mistake stable as everything being in equilibrium in the body which isn’t true.

Stable could also mean for the student that nothing is fluctuating or changing in either the external environment (ex. temperature) or internal environment (ex. body)

2. Homeostasis is the same for everyoneTechnically the term homeostasis could be confusing it suggests that the body needs to maintain a “steady-state” internal environment.

This might be considered as the same temperature levels, pH and/or blood sugar levels for everyone, but that’s also not true.

Potential Student Difficulties

3. Assuming the kidney collects urine

This can be confusing because the kidney filters the blood and eliminates a variety of potentially harmful substances but it also relieves the body of excess substances that otherwise do not need to be reabsorbed.

4. The Excretory System allows everything to pass

throughThe excretory system is not an open system that allows all substances to pass through, there are many different control mechanisms that allow for the passage of certain substances for example water or ions.

Potential Student Difficulties

1. Homeostasis means stable

The body is actually always reacting to its external environment (which is also constantly changing), in order to adapt and create stable conditions internally.

The human body is always monitoring what’s happening and actively making changes to maintain live-able conditions.

2. Homeostasis is the same for everyone

Everyone is an individual therefore our bodies regulate our internal environments in different ways. Not everyone has the same blood pressure as we know you can have low or high blood pressure. As well children usually have lower blood pressure than adults therefore their regulation differs from other individuals. For the most part the internal body temperature should be at approximately 37°C but that varies among individuals. Body temperature can also vary according to the external conditions like how hot or cold it is outdoors.

Possible Solutions to Student Difficulties

3. Assuming the kidney collects urine

The best way to explain this would be through animations and diagrams showing what exactly comes out of the blood and or what the kidney’s functions are. There is a good diagram in this presentation which can be accompanied with an explanation on slide 10.

4. The Excretory System allows everything to pass

throughI love the animation for ADH because it’s a perfect illustration of how reabsorption of water occurs. (slide 23) Also perhaps creating a class chart or concept map of which ions or substances get transported through certain membranes, for example the collecting duct transports water, salt (NaCl), urea, uric acid and minerals.

Possible Solutions to Student Difficulties

Dry fit t-shirts that help keep you cool or parkas to keep you warm (clothing to regulate body temperature)Diabetes Mellitus and Diabetes InsipidusChronic renal diseasesPerformance-enhancing drugs (steroids) and their affect on homeostasisEnergy drinks, coffee, coke etc. and their affect on homeostasisAlcohol and illegal drugs and their affect on homeostasisEffects of medically prescribed drugs on homeostasis (ex. diuretics)Kidney Dialysis and transplants

Practical Applications

Gerards, Susan (2011). Biology 12. Toronto: McGraw-Hill Ryerson. Provides background information and diagrams for lessons.

Kidney Tutorial http://www.biologymad.com/resources/kidney.swf Provides more background information of the kidney for students to review.

Control, Regulation and Feedback Tutorial http://bcs.whfreeman.com/thelifewire/content/chp41/41020.html Gives overview of feedback mechanisms and how the body controls itself. Homeostasis Lesson http://www.lionden.com/homeostasis.htm Overview of homeostasis.

Kidney Quizhttp://www.zerobio.com/target_practice_quiz/target_practice_quiz_kidney.htm Allows students to self-quiz themselves on their knowledge of the kidney.

Resources

Gizmo: Human Homeostasis http://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=519 Interactive simulation for students to understand how the human body regulates its water, temperature and activity levels.

Gizmo: Drug Dosage http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=525 Interactive simulation for students to investigate how drug dosage affects the body.

Khan Academy: Kidney and Nephron Overview http://www.khanacademy.org/science/biology/v/the-kidney-and-nephron?playlist=Biology An interactive video providing an overview of both the kidneys and the nephrons.

Easy Study Canada http://easystudy.ca/?p=2132 This is an exam review guide of grade 12: homeostasis.

 The Human Excretory System on Slideshare http://www.slideshare.net/Sianfergs/the-human-excretory-system-10220059 This slideshow goes through everything from excretion and homeostasis to the functions of the kidneys etc.

Resources continued

 YouTube - Commoncraft: The Excretory System http://www.youtube.com/watch?v=47OKHDqu2Hc This video is a cool way of explaining or giving an overview of the excretory system.

 Kidney Dissection Mini-Lab http://www.imarksweb.net/book/kidney+dissection+answers/ This is a pdf document that is located on my computer or it can be found at the site above.

 YouTube – Positive and Negative Feedback Loops http://www.youtube.com/watch?v=CLv3SkF_Eag&feature=related This video gives a super thorough explanation of negative versus positive feedback with real life examples, courtesy of Mr. Anderson.

 YouTube – Seinfeld: George’s Gore-Tex Coat http://www.youtube.com/watch?v=lt6KRKHpKhY This video was meant just as a minds-on activity, to get the students to think outside of the box and consider why this could be an example of homeostasis.

 Virtual Labs Renal https://sites.google.com/site/virtuallabsrenal/anatomy/adh-secretion This is a great simulation of ADH and how it functions within the body.

 YouTube – Renin-Angiotensin-Aldosterone System http://www.youtube.com/watch?feature=fvwrel&NR=1&v=PDE2qdS2ZvY This is a hand-written tutorial, therefore it has drawings as well as an oral presentation on video explaining this hormone complex.

Resources continued