Biology Question ......please help?

Question

Which gland experiences shrinkage or atrophy when exposed to stressors

Answer 1

The pituitary gland, which secretes ACTH, which, in turn, activates the adrenal gland to secrete the stress hormone cortisol, is the gland that is affected. However, if this does not work, the adrenal gland expands, if the hormone 21 hydroxalase is not present. The pre-cursor, 17-OHP, is tested for existence in CAH,but, that would result in hyperplasia, or enlargement of the adrenal gland. Hypoplasia, or shrinkage of the adrenal gland, by stress, is something that would have to be affected by a lack of enough ACTH emitted by the pituitary gland. Ah, so that is your answer, perhaps. Well, those are my thoughts, and what I know of the adrenal/stress situation. I apologize if it wasn't any help. Good luck; perhaps that will give you something to go on. :)

Answer 2

New studies of human brains show stress may shrink neurons
STANFORD -- The first direct evidence that stress can shrink a crucial part of the human brain is being compiled by scientists using new, high-resolution magnetic resonance imaging (MRI) scans, according to a Stanford expert on stress and the brain.

In a review article in the Aug. 9 edition of the journal Science, biological sciences Professor Robert Sapolsky said that the work of several research groups shows links between long-term stressful life experiences, long-term exposure to hormones produced during stress, and shrinking of the part of the brain involved in some types of memory and learning.

Sapolsky studies the effects of stress and stress hormones on wild baboons in Africa and on rats in his Stanford laboratory. He is the author of a popular book, Why Zebras Don't Get Ulcers, on the physiology of the stress response. He said that for 20 years, he and other stress physiologists have wished for a direct way to study the effects of stress on the human brain.

Research by Sapolsky and others has shown that some of those hormones, called glucocorticoids, spell bad news when brain cells are exposed to them for a long time ­ at least in the brains of rats.

Glucocorticoids can cause rats' brain cells to shrivel, as the dendrite branches that they use to communicate with other neurons wither away. Prolonged exposure can kill the neurons or make them vulnerable to destruction during a brain injury or stroke.

The researchers also know that long-term exposure to stress hormones is a fact of life for some animals. Studying a troop of wild baboons, Sapolsky has shown that the same glucocorticoids that flood the bloodstream during a stressful event remain at high levels for months or years if the baboon has a stressful life ­ for example, if he's always in fear of an attack by the dominant male in his troop.

The parallels are obvious with stressful human lives. But there has been no way to poke inside the living human brain and see if our neurons are more robust than a rat's, or if stress hormones actually can damage our brains.

Answer 3

Exposure to stress hormones, these studies suggest, “can significantly change the shape of the largest neurons in the hippocampus and can even kill them.” Stress can also suppress the production of new neurons after birth. Animal and human studies have also shown that abuse and neglect can reduce the size of the corpus callosum, which facilitates communication from one brain hemisphere to the other.