14.4.3

Urinalysis

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Urinalysis

Urine samples are useful diagnostic tools in medicine. They are convenient as collecting urine samples can be easier than collecting blood.

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Protein

  • Protein in urine is called proteinuria.
  • Proteinuria indicates damage to the kidneys.
  • Protein molecules are normally too large to pass through the glomerulus. Protein in the urine can suggest:
    • High blood pressure. High blood pressure can force protein through the glomerulus into the proximal convoluted tubule.
    • Leaky glomerular kidneys. This can be due to infection, diabetes, or inflammation in the kidneys.
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Glucose

  • Glucose is small enough to pass through the glomerular capillaries and enter the nephron.
  • However, most glucose is selectively reabsorbed in the proximal convoluted tubule (PCT).
  • If the amount of glucose entering the renal filtrate reaches a certain threshold, not all the glucose can be reabsorbed.
  • This leads to glucose in the urine.
    • As the glucose in urine originates from blood, high urine in glucose can suggest high blood glucose.
  • Glucose in urine suggests diabetes.
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Ketones

  • Ketones in the urine can also suggest diabetes.
  • Individuals with diabetes have high blood glucose. Because the glucose is in the blood rather than in cells, the glucose cannot be used for respiration.
  • This means cells respire using other respiratory substrates, namely lipids.
  • Respiring lipids produces ketones.
    • This metabolic state is sometimes referred to as "ketosis".
  • Ketones are excreted in urine.

Jump to other topics

1Cell Structure

2Biological Molecules

3Enzymes

4Cell Membranes & Transport

5The Mitotic Cell Cycle

6Nucleic Acids & Protein Synthesis

7Transport in Plants

8Transport in Mammals

9Gas Exchange

10Infectious Diseases

11Immunity

12Energy & Respiration (A2 Only)

13Photosynthesis (A2 Only)

14Homeostasis (A2 Only)

15Control & Coordination (A2 Only)

16Inherited Change (A2 Only)

17Selection & Evolution (A2 Only)

18Classification & Conservation (A2 Only)

19Genetic Technology (A2 Only)

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