May 9, 2011

The hypothalamus and pituitary gland

The hypothalamus and pituitary gland:-

The pituitary gland is called the “master gland” but it is under the control of the hypothalamus. Together, they control many other endocrine functions. They secrete a number of hormones, especially several which are important to the female menstural cycle, pregnancy, birth, and lactation (milk production). These include follicle-stimulating hormone (FSH), which stimulates development and maturation of a follicle in one of a woman’s ovaries, and leutinizing hormone (LH), which causes the bursting of that follicle (= ovulation) and the formation of a corpus luteum from the remains of the follicle.
There are a number of other hypothalamus and pituitary hormones which affect various target organs.
One non-sex hormone secreted by the posterior pituitary is antidiuretic hormone or ADH. This hormone helps prevent excess water excretion by the kidneys. Ethanol inhibits the release of ADH and can, thus, cause excessive water loss. That’s also part of the reason why a group of college students who go out for pizza and a pitcher of beer need to make frequent trips to the restrooms. Diuretics are chemicals which interfere with the production of or action of ADH so the kidneys secrete more water. Thus diuretics are often prescribed for people with high blood pressure, in an attempt to decrease blood volume.
Another group of non-sex hormones that many people have heard of is the endorphins, which belong to the category of chemicals known as opiates and serve to deaden our pain receptors. Endorphins, which are chemically related to morphine, are produced in response to pain. The natural response to rub an injured area, such as a pinched finger, helps to release endorphins in that area. People who exercise a lot and push their bodies “until it hurts” thereby stimulate the production of endorphins. It is thought that some people who constantly over-exercise and push themselves too much may actually be addicted to their own endorphins which that severe exercise regime releases.