Physiology 2130 Lecture Notes - Thyrotropin-Releasing Hormone, Anterior Pituitary, Thyroid
21 May 2013
School
Department
Course
Professor
Document Summary
The endocrine system consists of a series of glands that secrete different hormones into the blood. These hormones then travel throughout the body to their target site to initiate their effect. Actions of endocrine system are slower to take effect than nervous system but they last longer and are generally more widespread throughout the body. Glands group of specialized cells that synthesize, store and release hormones hormones circulate throughout the body to specific target cells that have receptors for the hormone. Hormones: tyrosine (thyroxine, triiodothyronine) thyroid gland, protein (calcitonn, parathyroid, pituitary and pancreatic) hypothalamus, steroid (cortisol, aldosterone, estrogen, progesterone and testosterone) cholesterol. Protein hormones hydrophilic = circulate freely in blood. Receptor = must be located on the cell membrane of target cell. Steroid/thyroid hormones hydrophobic = require a protein carrier to help circulate. Hormones are secreted into the blood in pulses by a very specific stimulus and in amounts that vary with the strength of stimulus.
