A marathon runner took only 1 litre of water with him when he set off on a race
on a hot day.
Describe the changes in his body to try to maintain normal body temperature.
Describe the role of the hypothalamus in regulating the water balance of his
body
Thermoregulation
• When environmental temperature is high
• Receptors in the skin detects this
• Impulses are send to the Hypothalamus
• Which sent impulses to the blood vessels in the skin
• These blood vessels become wider/dilate/increase in diameter/vasodilation
• More blood flows through the skin
• More heat is therefore lost
• from the body - Through radiation
• The sweat glands
• Produce more sweat
• That evaporates from the skin’s surface
• Leading to more heat is lost
• Cooling down the body
Hypothalamus
• will respond to information received from osmoreceptors
• To release more ADH into the blood
• Higher concentration of ADH increases the permeability
• of the renal tubules/distal convoluted and collecting tubules
• Allowing more water to be reabsorbed from the filtrate
• Passing into the surrounding blood capillaries
• Increasing the quantity of water in the blood
• Less urine will be excreted/more concentrated
on a hot day.
Describe the changes in his body to try to maintain normal body temperature.
Describe the role of the hypothalamus in regulating the water balance of his
body
Thermoregulation
• When environmental temperature is high
• Receptors in the skin detects this
• Impulses are send to the Hypothalamus
• Which sent impulses to the blood vessels in the skin
• These blood vessels become wider/dilate/increase in diameter/vasodilation
• More blood flows through the skin
• More heat is therefore lost
• from the body - Through radiation
• The sweat glands
• Produce more sweat
• That evaporates from the skin’s surface
• Leading to more heat is lost
• Cooling down the body
Hypothalamus
• will respond to information received from osmoreceptors
• To release more ADH into the blood
• Higher concentration of ADH increases the permeability
• of the renal tubules/distal convoluted and collecting tubules
• Allowing more water to be reabsorbed from the filtrate
• Passing into the surrounding blood capillaries
• Increasing the quantity of water in the blood
• Less urine will be excreted/more concentrated
