[SOLVED] Renal Function

Renal Function

Renal Function (2)
Introduction
The kidneys form approximately 180 liters of filtrate per day while only 1% is lost as urine. One of the kidneys’ critical functions it to maintain plasma fluid & electrolyte balance. The nephrons are able to respond to changes in fluid & electrolyte concentrations & vary urine output. The nephrons use several mechanisms to control urine output. They have both intrinsic & extrinsic regulatory mechanisms. Intrinsic mechanisms consist of the myogenic mechanism & macula dense cell controls while extrinsic mechanisms include endocrine & nervous system controls.
The intrinsic controls mainly function to quickly alter urine output in response to changes in blood volume & blood pressure. The extrinsic controls also respond to blood volume & pressure but may supersede all others (as in the sympathetic nervous system) or respond to blood osmolarity. The hormones ADH & aldosterone are critical hormones for regulating urine output.
This laboratory experiment will show how ingesting various foods & drinks can vary plasma osmolarity & alter glomerular filtration rate to cause changes in urine formation/excretion as the kidneys regulate urine output. Alterations in urine output will be measured & assessed by examining quantity & concentration of urine.
Objectives:
1. To collect & analyze your own urine.
2. To predict & test kidney responses to ingestion of various fluids & foods.
3. To summarize intrinsic & extrinsic regulatory factors on urine production.
Procedures:
All students will be given a treatment group to test. All students will collect baseline urine samples at beginning of laboratory, measuring urine volume & color. Students will use the urine sample cups provided & all collection will be done in the restroom. You are to work with ONLY your own specimen. At least one student (any are welcome to participate) should also test their urine with the dipsticks before & after & record all relevant information. Gloves are provided for your use. Please wash any lab equipment (with the supplied disinfectant) that your urine comes in contact with. Dispose of urine cups in the trash bin provided.

 

Students will record the following information from their urine sample. At least one student should also use a dipstick to gather the information in the later table.
Student 1. Musa 2. Henry 3. Alex 4. Evelyn
Urine Volume 20 ml 15 ml 15 ml 15ml
Urine Color Clear yellowish yellowish clear
Specific gravity N/A N/A 1.025 +++ N/A

Then students will choose one of the following to ingest: (Note: if you have any health problems such as hypertension, cardiac arrhythmias, or are pregnant you will be in group four).
1.) Caffeinated cola or drink
= Evelyn
2.) Non-caffeinated cola or drink
= Alex
3.) Salty food (popcorn, chips) only – no beverages = Henry
4.) Water = Musa

Test Result Normal Range Meaning of the test
Specific Gravity 1.025 1.016-1.022 Based on the pKa change of certain pretreated polymeric ion exchange resin in relation to ionic concentration in the presence of an indicator, colors range from blue green in urine of low ionic concentration through green and yellow green in urines of increasing ionic concentration.
pH 6 5-8 Double indicator (methyl red and bromothymol blue) principle that gives a broad range of colors, from orange, yellow, green, and blue.

Leukocytes 25 WBC/picol. Yield negative result Color change ranging from beige to pink that occurs when esterase is hydrolyzed then coupled with diazonium salt to form a colored azo dye.

Nitrite Negative Negative Everything is fine. No sign of infection.
Protein 10(0.1) 20mg/dL Protein is low, which indicates her blood sugar isn’t high enough.
Glucose Negative Small amount
Up to 30mg/dL It indicates that the glucose
Ketone 5 (0.5) mg/100mL Appear in large amount N/A
Urobilinogen 0.1 (1.7) +-mg/100mL Male: (0.3-2.1mg/2 hrs.)
Female:(0.1-1.1mg/ 2hrs) Everything is fine. Alex is a female and is in the range where females are in.
Bilirubin Negative Not detectable N/A
Blood 10 RBC/picol. Negative Her blood is ok.

While you are waiting, look up the results of your initial dipstick test. For each result, indicate the normal range, whether the result was normal. Record what an abnormal result would indicate.
Results:
Students will wait 90 minutes after finishing the food or drink & then collect urine again & record the following:
Student 1 Musa 2 Henry 3 Alex 4 Evelyn
Urine Volume 20 ml 20 ml 20 ml 20ml
Urine Color clear Yellowish yellowish Clear
Specific Gravity na na 1.025 +++ na

Questions:
What changes (if any) were recorded for student #1 (the caffeinated drink)?

Why do you think you observed these changes? Think about intrinsic & extrinsic regulatory mechanisms. What effects might caffeine have?

What changes (if any) were recorded for student #2 (the non-caffeinated drink)?

Why do you think you observed these changes? Think about intrinsic & extrinsic regulatory mechanisms.

What changes (if any) were recorded for student #3 (salty snack)?

Why do you think you observed these changes? Think about intrinsic & extrinsic regulatory mechanisms.

What changes (if any) were recorded for student #4 (water)?

Why do you think you observed these changes? Think about intrinsic & extrinsic regulatory mechanisms.
Review Questions:
How does the myogenic mechanism respond to increased blood pressure in the afferent arteriole? Think about how changes in blood pressure affect the stretch of the afferent arteriole & how the myogenic mechanism maintains GFR.

What type of filtrate will stimulate the macula dense cells to increase the diameter of the afferent arteriole? What type of filtrate would require an increase in filtration rate?

What are three triggers for the release of aldosterone?

5.) What plasma osmolarity will inhibit the release of ADH? Renal Function Renal Function V