Question 1 (5 points)
During breastfeeding, the stimulus of the baby sucking on the nipple increases the amount of milk produced by the mother. The more sucking, the more milk is usually produced. Is this an example of negative or positive feedback? Explain your answer. What do you think might be the evolutionary benefit of the milk production regulation mechanism you described?
Question 2 (5 points)
The level of a sex hormone, testosterone (T), is controlled by negative feedback. Another hormone, gonadotropin-releasing hormone (GnRH), is released by the hypothalamus of the brain, which triggers the pituitary gland to release luteinizing hormone (LH). LH stimulates the gonads to produce T. When there is too much T in the bloodstream, it feeds back on the hypothalamus, causing it to produce less GnRH. While this does not describe all the feedback loops involved in regulating T, answer the following questions about this particular feedback loop.
a. What is the stimulus in this system? Explain your answer. b. What is the control center in this system? Explain your answer. c. In this system, is the pituitary considered the stimulus, sensor, control center, or effector? Explain your
answer. Question 3 (5 points) What are the differences between a neurotransmitter receptor and a sensory receptor? Give two (2) examples of each to illustrate these differences.
Question 4 (5 points)
a.Define hyposecretion and give an example of an endocrine disorder involving hyposecretion. Be sure to include the name of the hormone involved.
b.Define hypersecretion and give an example of an endocrine disorder involving hypersecretion. Be sure to include the name of the hormone involved.
Sample Solution