• Submitted By: gresal
  • Date Submitted: 11/28/2008 4:50 AM
  • Category: Science
  • Words: 2230
  • Page: 9
  • Views: 1053

Homeostasis is the process by which a living organism without thought controls internal conditions naturally, adjusting precisely to any environmental changes.
In order for the body to change and adapt to environmental changes it is important the brain communicates effectively with all organs and glands. The hypothalamus within the brain is considered the control centre of the endocrine system. The endocrine system and the nervous system are so closely associated that they are collectively called the neuroendocrine system. Neural control centers in the brain control the release of hormones in the pituitary gland and in addition controls water balance, sleep, temperature, appetite, and blood pressure. The hypothalamus also serves as a “mediator” between the nervous and endocrine systems. When a certain hormone is below its desired levels in the body, such as the hormone thyroxime the hypothalamus releases its own hormone, hypothalamin, to activate the pituitary gland to secrete the hormone thyrotropin, which then in turn will cause the thyroid gland to produce more thyroxine. The endocrine system is composed of glands that release their hormones directly into the bloodstream to help adapt the body adapt. These glands include the pituitary gland, the pineal gland, the hypothalamus, the thyroid gland, the parathyroid glands, the thymus, the adrenal glands, the ovaries (in females) or testes (in males), and the pancreas.

Negative Feedback

The method in which our body maintains a state of homeostasis is called negative feedback. Negative feedback requires a receptor, a control center, and an effector. A receptor is the structure that monitors internal conditions. For instance, the human body has receptors in the blood vessels that monitor the pH of the blood. The blood vessels contain receptors that measure the resistance of blood flow against the vessel walls, thus monitoring blood pressure. Receptors sense changes in the body and...

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