Question

Which of the following statements is false?

a. General adaptation syndrome occurs under prolonged or chronic stress and begins with the alarm reaction followed by the resistance reaction and then exhaustion.
b. ADH and oxytocin pass from the hypothalamus to the posterior pituitary via the pituitary portal vein.
c. Most of the feedback mechanisms that regulate hormones are negative mechanisms.
d. Water soluble hormones cannot diffuse through the plasma membrane as such they act by a mechanism involving cAMP and a cascade reaction rather than by direct gene activation.
e. Hormones of the endocrine system have a variety of functions ranging from regulation of metabolic activities in other cells, to immunity to growth and development.

Answer 1

The false statement in the list provided by the student is option (b), which incorrectly states that ADH and oxytocin travel to the posterior pituitary via the pituitary portal vein; instead, they travel via nerve axons.

Step-by-step explanation:

In addressing the student's question regarding which statement is false, it is crucial to understand the different aspects of the endocrine system and hormone regulation. The following discusses each option provided:

• General adaptation syndrome does indeed occur under chronic stress and has three phases: alarm reaction, resistance reaction, and exhaustion. This statement is true.

• The statement that ADH and oxytocin pass from the hypothalamus to the posterior pituitary via the pituitary portal vein is false. These hormones actually travel down nerve axons to reach the posterior pituitary. The correct option is option (b), which is the false statement.

• It is true that most feedback mechanisms regulating hormones are negative feedback mechanisms.

• Water soluble hormones indeed cannot diffuse through the plasma membrane; they act by mechanisms involving cAMP and a cascade reaction rather than by direct gene activation, so this statement is true.

• Hormones of the endocrine system have functions ranging from regulation of metabolic activities, immunity, growth, and development, so this statement is true.

The false statement in this question is option (b), which claims that ADH and oxytocin travel to the posterior pituitary via the pituitary portal vein.