Transport maximum

Definition

Transport maximum is the maximum rate at which a substance can be reabsorbed by the kidneys. It occurs when all transport proteins are saturated and cannot handle any additional load of the substance.

5 Must Know Facts For Your Next Test

1. Transport maximum is often related to glucose reabsorption in the kidneys.
2. When the blood concentration of a substance exceeds its transport maximum, it will appear in urine.
3. The concept of transport maximum applies to substances that rely on carrier proteins for reabsorption.
4. It is crucial for understanding conditions like diabetes mellitus where excess glucose spills into urine due to exceeding the transport maximum.
5. Transport maximum helps determine renal threshold levels for various substances in the body.

Review Questions

• What happens when a substance's blood concentration exceeds its transport maximum?
• How does transport maximum relate to glucose reabsorption in diabetic patients?
• Why is understanding transport maximum important for renal physiology?

Related terms

Renal Threshold: The plasma concentration at which a substance begins to appear in urine.

Glomerular Filtration Rate (GFR): The rate at which blood is filtered through the glomeruli of the kidney.

Carrier Proteins: Proteins that facilitate the transport of substances across cell membranes during reabsorption.