04+Endocrinology

Endocrinology Chapter Eleven __//** Content Summary **//__ //The purpose of chapter eleven is to inform one on the different types of endocrine glands in the human body. Not only that, there is a focus on the major hormones that are associated with each endocrine gland.//

//One of the major concepts in this chapter was focused on hormone interactions. Hormone interactions play a large part in the endocrine system within your body. The different tissues of the body are able to react to several different hormones. The body can do this because there are several different ways that hormones can act together to get a message across. The first way is with a synergistic action. A hormone can work together with another hormone in order to put their strengths together to make them seem stronger. By acting together they produce a larger and more dominant effect, because they are combining their strengths instead of acting alone. The next method that two hormones can work together would be to use the permissive effect. In this case the two hormones almost act separately, but they hit the target organ one after another. The first acts as though it is a decoy, but in fact he does nothing but prime the organ so that when the second hormone arrives it has a much larger effect than if it would have been all alone with out the precursor of the first hormone.// //There is one other way hormones effect each other’s actions, but it is in a negative way this time. This is called the antagonistic effect. With this effect you get the opposite of the last two that were discussed, and the hormones are pulling in opposite directions. The best analogy to describe this would be to imagine your extensor and flexor muscles. They work on the same part of the body, but at the same time they do the exact opposite movements. The antagonistic effect of the hormones would basically be that of the muscles, canceling each other out.// Source (Physiology Book)

//At the base of the forebrain, directly below the hypothalamus is the pituitary gland, which is also a very important topic discussed in this chapter. The gland is made up of two main parts, the anterior and the posterior aspects. The posterior and anterior receive their hormones from different sources. The anterior makes its own hormones, under the direction of the hypothalamus and the posterior just stores hormones from the hypothalamus with producing any of its own. The 2 hormones that are stored in the posterior pituitary gland are the vasopressin and the oxytocin. Along with storing and releasing these two, it also releases ADH. The anterior pituitary gland creates and secretes 6 different trophic hormones. Trophic hormones travel in the bloodstream until they reach their target organs. The anterior pituitary itself, however, does not decide upon the release of these hormones. The hypothalamus, along with the feedback it receives from the target gland hormones and other inhibiting factors all play a role in the discretion of the hormones release.// Source (Physiology Book) [|Glands of the Human Endocrine System]

//One last concept discussed in this chapter has to deal with the adrenal gland. The adrenal glands are specific glands that sit atop the kidneys. The developmental rate of these glands varies, but they all end up with an inner medulla and an outer cortex. The medulla releases Norepinephrine and Epinephrine and this is controlled by the ANS. The cortex releases Cortisol and Aldosterone which is controlled by the hormone ACTH, and in turn the Anterior Pituitary. Levels of stress effect the amount of each hormone released. In times of high stress, excess Cortisol can be released and this can be harmful. Damaging results can include an atrophy of the hippocampus, reduced sensitivity of tissues to insulin, inhibition of vegas nerve activity, and the suppression of// growth hormone. Source (Physiology Book)

__//**Application **//__ //Within chapter eleven, the major concept that I was able to relate with was the information provided on the female reproductive system. For example, when discussing the posterior pituitary, the book stated two types of hormones that are stored and released. The one hormone that I could relate to was oxytocin. Oxytocin stimulates contractions of the uterus during birth. I found it very interesting to learn these new terms that applied to my body when I was giving birth. Not only that, it was great to actually gain the knowledge of understanding what my body was going through at that particular time. Another function of oxytocin is to set off contractions of the mammary alveoli for milk production from the breasts. This is something else that I can relate to due to giving birth and breast-feeding my child. Therefore, I enjoyed learning a little bit more about myself during this chapter.//

__//**Essential Questions **//__ //The hypothalamus regulates the actions of the pituitary glands by regulating when they secrete their hormones. The posterior pituitary gland also has to store the hormones that the hypothalamus creates.//

//The anterior pituitary produces and stores Growth Hormone. This hormone promotes growth, protein synthesis, and movement of the amino acids into the cells. The posterior pituitary gland does not produce any hormones, however it does store two hormones that the hypothalamus produces. One of these hormones is oxytocin, which assists women who are in labor. It is released to increase uterine contractions in order to help conceive. Along with this it also enables the mammary glands to have the ability to express milk.//

//Trophic hormones are hormones that are released and travel in the blood stream until they reach their target organs. Their role in communication is huge because they are able to travel to all parts of the body to send and receive messages.//