NEET2007ZoologyNeural Control and CoordinationActual
Which of the following is an example of negative feedback loop in humans?
Options
- Asecretion of tears after falling of sand particles into the eye
- Bsalivation of mouth at the sight of delicious food
- Csecretion of sweat glands and constriction of skin blood vessels when it is too hot
- Dconstriction of skin blood vessels and contraction of skeletal muscles when it is too cold.
Correct answer
D. constriction of skin blood vessels and contraction of skeletal muscles when it is too cold.
Step-by-step 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 (" T₄ and T₃ ") are synthesized and secreted by thyroid glands and affect