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Thermoregulation and the kidneys
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Homeostasis keeps conditions inside the body stable. Temperature and water balance are two key examples. Separate Biology only.
Temperature control
The hypothalamus monitors blood temperature (about 37 °C).
Too hot: sweating, vasodilation (blood vessels near the skin widen), hairs lie flat.
Too cold: shivering, vasoconstriction, hairs stand up.
Too hot: sweating, vasodilation (blood vessels near the skin widen), hairs lie flat.
Too cold: shivering, vasoconstriction, hairs stand up.
The kidneys
Kidneys filter the blood, then reabsorb useful substances such as glucose and some water.
Urea, excess water and ions leave as urine.
The nephron is the kidney's filtering unit.
Urea, excess water and ions leave as urine.
The nephron is the kidney's filtering unit.
ADH (Higher)
When the blood is too concentrated, the pituitary releases ADH, which makes the kidney tubules reabsorb more water. Less, more concentrated urine is produced.
Kidney failure is treated by dialysis or a transplant.
Kidney failure is treated by dialysis or a transplant.
Why do you produce less urine on a hot day?
- You lose more water by sweating.
- The blood becomes more concentrated, so more ADH is released.
- The kidneys reabsorb more water.
Answer: More ADH means more water is reabsorbed.
The hypothalamus controls temperature with sweating, shivering and changes in blood flow. Kidneys filter blood and reabsorb useful substances. ADH controls how much water is reabsorbed.
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