Which statement is incorrect Select one a Endocrine glands l

Which statement is incorrect?

Select one:

a. Endocrine glands lack ducts.

b. The effect of hormones is shorter than the effect of nerve impulses.

c. Steroid hormones are carried in the blood by transport proteins.

d. Hormones may have widespread, distant effects on the body.

e. A common second-messenger is cyclic AMP.

The secretion of ________ by the posterior pituitary gland is the only hormone controlled by ________.

Select one:

a. antidiuretic hormone; positive feedback

b. oxytocin; positive feedback

c. oxytocin; negative feedback

d. antidiuretic hormone; negative feedback

Solution

1)

Hormones comprise of short peptides or steroid molecules that are released in response to a stimuli. They are regulated by the endocrine system. Nerve impulses refer to the tranmission of a message through the nerves via action potentials, and are aided by neurotransmitters. They are regulated by the nervous system.
Now, responses to nervous system stimulation are rapid, but short lived. On the other hand, the response of the endocrine system after stimulation may not be as rapid as those of nerve impulses. However, their effect is more prolonged as compared to nerve impulses.

Therefore, the incorrect option is Option B - The effect of hormones is shorter than the effect of nerve impulses.

2)
The posterior pituitary is a part of the endocrine system. It is simply a collection of axons projecting from the hypothalamus.They act as storage vesicles for two important peptide hormones - Oxytocin and Anti-Diuretic hormone (ADH). Oxytocin is released during childbirth and aids in the contraction of the uterine muscle walls. ADH is released in response to low fluid levels in the body. While ADH has a negative feedback loop mechanism, Oxytocin is one of the few hormones to have a positive feedback loop mechanism. In short, contraction of the uterine muscles promote the release of even more oxytocin.

Therefore, the correct option is Option B - The secretion of OXYTOCIN by the posterior pituitary gland is the only hormone controlled by POSITIVE FEEDBACK.