Which of the following is an example of a negative feedback mechanism in regards to hormone regulation?
A)ADH is released from the pituitary causing water to be reabsorbed in the kidneys. B)A baby suckles in order to stimulate milk production. C)The uterine contractions during labor stimulate oxytocin production. D)All of these are examples of a negative feedback mechanism. E)None of these are examples of a negative feedback mechanism.
The same hormone has considerably different effects in different species.The hormone thyroxine in humans stimulates metabolism,but in frogs it induces metamorphosis from tadpole to adult frog.This indicates that
A)the target tissues have evolved different responses. B)metamorphosis is caused by a change in body metabolism. C)the organisms have absolutely no evolutionary relationship. D)the chemical composition of the hormone is actually slightly different. E)the origin of the hormone makes a difference in the effect the hormone has on target tissues.
Which of the following statements about hormones is NOT true?
A)Hormones are secreted into the bloodstream. B)Hormones are released from exocrine glands. C)Hormones may be classified as peptides or steroids. D)Hormones usually affect a target organ. E)Cells that react to a hormone have specific receptors for that hormone.