Which of the following is an example of negative feedback loop in humans?
Which of the following is an example of negative feedback loop in humans?
secretion of tears after falling of sand particles into the eye
salivation of mouth at the sight of delicious food
secretion of sweat glands and constriction of skin blood vessels when it is too hot
constriction of skin blood vessels and contraction of skeletal muscles when it is too cold.
Solution
When the set point of hypothalamus is disturbed by high temperature, it stimulates vasodilation and sweating while in low temperature there is vasoconstriction and shivering.
Related Theory
Feedback loops are used extensively to regulate secretion of hormones in the hypothalamic-pituitary axis. An important example of a negative feedback loop is seen in control of thyroid hormone secretion. The thyroid hormones thyroxine and triiodothyronine (" $T_4$ and $T_3$ ") are synthesized and secreted by thyroid glands and affect metabolism throughout the body.