Kidney Homeostasis

Kidney Homeostasis By: Marion Paxton and Rosanna Parise

Agenda: Introduction  Expectations  Lesson Sequence  Assessment and Evaluation  Activity/Student Lab  Student Misconceptions  Demo  Practical Applications  Resources 

Introduction: The Kidney 

Main function: to filter the blood to remove waste products and to adjust salt concentrations in the blood

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Associated with the excretion of cellular wastes (urea, uric acid, creatinine)

The Kidney Cont’d 

Composed of 3 sections: ◦ Outer cortex ◦ Medulla ◦ Inner pelvis

Kidney Cont’d 

In the cortex and medulla, there are about 1,000,000 nephrons – these act as filters and are composed of: ◦ ◦ ◦ ◦ ◦ ◦

Bowman’s capsule The glomerulus Proximal tubule The loop of Henle Distal tubule Collecting duct Picture of the nephron on next slide

The Kidney Nephron

The Kidney Cont’d 

Please go to the following interactive site to learn more about the kidney: http://www.biologymad.com/resources/kidney.swf

The Kidney Cont’d 

Homeostatic mechanisms are in place to control the levels of water and electrolytes in the blood

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One very important hormone involved in this is called Antidiuretic Hormone (ADH)

Expectations 

The following are a list of expectations that will be covered through studying Kidney Homeostasis:

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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)

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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)

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E2.3 plan and conduct an investigation to study a feedback system (e.g., stimulus response loop)

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E3.1 describe the anatomy and physiology of the endocrine, excretory, and nervous systems, and explain how these systems interact to maintain homeostasis

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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 1: Kidney Structure and Function

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Lesson 2: The Nephron: Filtration and Reabsorption

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Lesson 3: Homeostasis: Feedback Mechanisms

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Lesson 4: Lab: The Physiological Effects of Coffee

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Lesson 5: Kidney Transplant Article and Case Study

Lesson 1: Introduction to the Kidney: Structure and Function 

KWL Chart – have students fill in KW now and L after lesson 5 (self assessment)

Intro Video:  http://www.youtube.com/watch?v=qxb2_d9ilEw 

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Group work: ◦ Provide students with basic diagram – have them fill in the name of each structure ◦ Then, they will complete a T chart on the structure and function of the following: kidney, renal veins, renal arteries, urinary bladder, urethra

Lesson 2: The Kidney Nephron: Filtration and Re-absorption

Lesson 2: The Kidney Nephron: Filtration and Re-absorption 

Teacher demo on passive transport

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Youtube video: 

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http://www.youtube.com/watch?v=glu0dzK4dbU

Interactive Site: 

http://www.biologymad.com/resources/kidney.swf

• Role play exercise where students are the filtrate and classroom desks are arranged as the nephron

• Worksheet: •

http://www.biologycorner.com/anatomy/urinary/kidney_coloring.html

Lesson 3: Homeostasis: Feedback Mechanisms

Lesson 3: Homeostasis: Feedback Mechanisms 

Quick review of the nephron – quiz

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Introduce hormone ADH and ADH feedback loop (refer to picture – slide 14)

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Have students read about this feedback loop in pairs – pg 117 (McGraw Hill Biology 12)

Lesson 3: Homeostasis: Feedback Mechanisms 

Students work in groups to come up with a way to demonstrate the ADH feedback loop to their peers

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Assign homework questions from textbook – to be taken up next day:  Pg 120 Q’s 4-6  Pg 134 Q’s 7, 12

Lesson 4: Lab The Physiological Effects of Coffee 

For this lab, students will design an experiment that allows them to investigate one physiological effect of consuming coffee (e.g. Effects on blood pressure, urine output, etc.)

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Refer to Word document for a more detailed description of this lab

Lesson 4 Lab: Safety Considerations 

It may not be appropriate for some students to participate as subjects in the Physiological Effects of Coffee Lab due to health concerns

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As students design their experiments, be sure to consult with each group to make sure that they don’t exceed their coffee intake

Lesson 5: Kidney Transplant Article and Case Study 

Students use an anticipation guide to read an article about kidney transplants in Canada.

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4 corners strategy used to discuss opinions

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A class debate about steroid use and kidney disease in body builders will follow. Refer to the following article:

http://www.nytimes.com/2009/12/10/sports/10stero ids.html?_r=1&scp=2&sq=steroids&st=cse 

Peer and self assessment

Assessment and Evaluation 

Lesson 1: KWL Chart – diagnostic and form of self assessment

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Lesson 2: Nephron Worksheet

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Lesson 3: Group presentations and textbook questions

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Lesson 4: Lab Report

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Lesson 5: Anticipation guide; peer and selfassessment

Student Difficulties 

Difficulty: ◦ Students may have difficulty understanding how and why different substances enter and leave the kidney tubule.

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Rectification ◦ 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. ◦ Youtube video:  http://www.youtube.com/watch?v=glu0dzK4dbU

◦ Interactive website:  http://www.biologymad.com/resources/kidney.swf **Note: Refer to summary handout for other rectifications.**

Student Difficulties cont’d 

Difficulty: ◦ Some students may have trouble understanding the feedback mechanism involved in controlling urine output.

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Rectification ◦ Use a flow chart to help students visualize the feedback mechanism. ◦ Group weaker students with stronger students during the problem solving activity.

Demonstration 

Passive Transport Lab ◦ Students will observe passive transport of a substance across a membrane

Practical Applications 

Effects of steroid use on kidney functioning

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Kidney transplants, dialysis and organ harvesting

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Effects of alcohol and caffeine on kidney homeostasis

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Chronic renal diseases

Resources 

Please refer to our summary for a list of the resources used to create this presentation

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