The Endocrine System PDF

‭The Endocrine System and Feedback Mechanisms‬ ‭-‬ ‭Most of the body’s processes are regulated by‬‭hormones‬‭(they are considered to be‬ ‭chemical‬‭messengers‬‭)‬ ‭-‬ ‭Hormones are created and secreted by organs or glands that have‬‭ducts‬‭– “pipes” or‬ ‭passageways that allo...

‭The Endocrine System and Feedback Mechanisms‬ ‭-‬ ‭Most of the body’s processes are regulated by‬‭hormones‬‭(they are considered to be‬ ‭chemical‬‭messengers‬‭)‬ ‭-‬ ‭Hormones are created and secreted by organs or glands that have‬‭ducts‬‭– “pipes” or‬ ‭passageways that allow the organ to secrete the chemicals directly into the bloodstream‬ ‭-‬ ‭Glands are specific to hormone production, whereas some organs can also secrete‬ ‭hormones along their usual function‬ ‭-‬ ‭The collective set of these organs and glands that secrete hormones important for‬ ‭homeostatic regulation are known as the‬‭endocrine‬‭system‬  ‭(‬‭negative‬‭means‬‭stop‬‭)‬ ‭(general feedback loop)‬ ‭-‬ ‭Hormones can be classified into two types based on their chemical structure:‬ ‭‬ ‭PROTEIN HORMONES: such as insulin‬ ‭‬ ‭STEROID HORMONES: such as cortisol (this is commonly found in many topical‬ ‭steroid creams)‬ ‭-‬ ‭Based on the chemical structures, each type of hormone has slightly different‬ ‭mechanisms of action and can affect cells through different methods‬ ‭-‬ ‭One particular gland that is of great importance in the endocrine system is the‬‭pituitary‬ ‭gland‬‭(located at the base of the brain, just in front‬‭of the brain stem)‬  ‭‬ ‭It is attached to the hypothalamus, an important monitoring center for autonomic‬ ‭(things you can’t control consciously) processes in your body (ie. Body‬ ‭temperature)‬ ‭‬ ‭It secretes a large number of hormones that are involved in various hormone‬ ‭axes‬ ‭(‭p ‬ osterior‬‭is directly connected to the nervous system,‬‭anterior‬‭is more of an‬ ‭adrenal gland response [not a nerve response])‬ ‭-‬ ‭The‬‭hormone axes‬‭(feedback loops) that will be studied‬‭are…‬ ‭‬ ‭Glucagon‬‭: for control of blood sugar levels‬ ‭‬ ‭Hypothalamic-Pituitary-Adrenal axis‬‭: to prepare the‬‭body for stress responses‬ ‭‬ ‭Hypothalamic-Pituitary-Thyroid axis‬‭: to control the‬‭release of thyroid hormone‬ ‭that affect metabolism and growth‬ ‭‬ ‭Parathyroid‬‭: to control Ca+ concentration in blood‬ ‭‬ ‭Hypothalamic-pituitary-testicular axis‬‭: controls secretion‬‭of testosterone and‬ ‭production of sperm‬ ‭‬ ‭Hypothalamic-pituitary-ovarian axis‬‭: controls secretion‬‭of estrogen and‬ ‭progesterone, ovum development and the menstrual cycle‬ ‭Glucose Regulation‬ ‭-‬ ‭Glucose is an essential molecule for cellular survival, its regulation is important‬ ‭-‬ ‭A specific concentration of glucose must be kept in the blood in order for cells to access‬ ‭the glucose they need to function in animals‬ ‭‬ ‭Glycogen‬‭is stored in the liver and muscles‬ ‭‬ ‭During times when blood glucose level is low, glycogen is broken down in order‬ ‭to release glucose into the bloodstream‬ ‭-‬ ‭A specific concentration of glucose must be maintained in the blood in order for cells to‬ ‭access the glucose they need to function‬ ‭‬ ‭“Normal” levels‬‭= ~ 90 mg/dL of blood‬ ‭‬ ‭Hyperglycemic‬‭= >130 mg/dL of blood‬‭(too much sugar)‬ ‭-‬ ‭Thirst (high blood osmolarity)‬ ‭-‬ ‭Frequent urination‬ ‭-‬ ‭Sugar in urine‬ ‭-‬ ‭Vision problems‬ ‭‬ ‭Hypoglycemic‬‭=