Lab 4: Renal Function Flashcards Preview

3) Mammalian Physiology > Lab 4: Renal Function > Flashcards

Flashcards in Lab 4: Renal Function Deck (44)
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1
Q

What is the major function of the urinary system?

A

Keeps chemicals and water in balance by removing urea (waste) from the blood

2
Q

What is urea produced from?

A

Foods containing protein, such as meat, poultry, and certain vegetables

3
Q

Where is urea carried?

A

In the bloodstream to the kidneys

4
Q

How many kidneys does a mammal contain? Where are they found?

A
  • Two kidneys

- Located below the ribs towards the middle of the back

5
Q

Which hormone is produced by the kidneys? What is its function?

A
  • Erythropoietin

- Aids in the formation of RBCs

6
Q

What are the filtering units of the kidneys?

A

Nephrons

7
Q

What does each nephron consist of?

A
  • Glomerulus: ball formed of small blood capillaries

- Renal tubule: small tube

8
Q

What forms the urine?

A
  • Urea
  • Water
  • Other waste substances
9
Q

What does urine pass through?

A

Nephrons, and down the renal tubules of the kidney

10
Q

What is the function of ureters? How many do we have?

A
  • Two ureters

- Carry urine from the kidneys to the bladder

11
Q

Which muscles continually tighten and relax to force urine downward?

A

Muscles in the ureter

12
Q

How often are small amounts of urine emptied into the bladder from the ureters?

A

About every 10 to 15 seconds

13
Q

Where is the bladder located?

A

Located in the lower abdomen

14
Q

How is the bladder held in place?

A

By ligaments that are attached to other organs and the pelvic bones

15
Q

What function does the bladder exert during relaxation and during contraction?

A
  • Relax and expand to store urine

- Contract and flatten to empty urine through the urethra

16
Q

How much urine can the typical adult healthy bladder store?

A

Up to 2 cups for 2 to 5 hours

17
Q

What are the functions of the two sphincter muscles?

A
  • Circular muscles that help keep urine from leaking

- Close tightly like a rubber band around the opening of the bladder

18
Q

What is the function of the nerves in the bladder?

A

Alert a person when it is time to urinate, or empty the bladder

19
Q

What is the function of the urethra?

A

The tube that allows the urine to pass outside of the body

20
Q

How does normal urination occur through nervous signalling?

A
  • The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder
  • The brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra
21
Q

What is the volume and composition of urine adjusted by? Why?

A
  • Neural and hormonal mechanisms

- To maintain constancy of volume and electrolyte concentrations in the body fluids

22
Q

What is usually accompanied by sodium reabsorption in the renal tubules? Why?

A
  • Chloride

- To maintain electrostatic neutrality

23
Q

How can the amount of sodium excreted be approximately determined?

A

By the estimation of chloride concentration

24
Q

The number of drops of silver nitrate is equal to what in this experiment?

A

The number of grams of sodium chloride per liter of solution

25
Q

How is specific gravity (or density) determined?

A

With a urinometer

26
Q

What is the specific gravity of pure water?

A

1.000

27
Q

What is the definition of specific gravity?

A

The ratio of the density (compactness) of a substance (urine) to that of distilled water at a specific temperature

28
Q

What does a higher specific gravity infer?

A

A higher composition of dissolved solids (urea, sodium chloride, etc.)

29
Q

How may a rough approximation of the total dissolved substances in urine may be obtained?

A

By multiplying the final two figures of the specific gravity reading by 2.66 (Long’s coefficient)

30
Q

What is the normal specific gravity of a 24-hour specimen of urine?

A

1.020 (range: 1.016 to 1.025)

31
Q

What does a specific gravity of 1.001 indicate?

A

Following ingestion of a large amount of fluids

32
Q

What does a specific gravity of 1.040 indicate?

A

Heavy perspiration

33
Q

What are the major components of urine?

A
  • 95% water
  • 2% urea
  • 0.18% sulphate
  • 0.12% phosphate
  • 0.1% creatine and sodium
  • 0.6% potassium and chloride
34
Q

What type of instrument is a urinometer?

A

Hydrometer

35
Q

What does each line of a urinometer represent?

A

0.001

36
Q

What is specific gravity a function of?

A
  • Number
  • Density
  • And weight of the solute particles present
37
Q

Specific gravity is used as a measure of the power of what?

A

Concentration power of the kidney

38
Q

What is the indicator in the chloride concentration procedure?

A

K2CrO4 (potassium chromate)

39
Q

What is the function of silver nitrate (AgNO3)?

A
  • Reacts with the chloride in urine to precipitate AgCl (silver chloride)
  • Any excess AgNO3 reacts with potassium chromate to form a reddish precipitate of silver chromate (Ag2CrO4), which indicates the endpoint
40
Q

Is specific gravity a physical or chemical characteristic?

A

Physical characteristic of urine measured through a chemical test

41
Q

When would a urine sample be recommended if a lab technician is looking for a very small amount of protein?

A
  • In the morning

- A concentrated morning urine specimen is superior to a diluted specimen

42
Q

What is the normal range of sodium in a random urine sample?

A

25 to 100 mEq

43
Q

How do you determined the number of mg from the mEq of sodium?

A

mg = mEq x 35.4

44
Q

What is the normal urine sodium value over a day?

A

40 to 220 mEq/L per day