Endocrine System Review Sheet PDF

ENDOCRINE SYSTEM ================ - **Note: Low FSH will cause low LH in the human body.** **[Female low FSH]: infertility, lack of monthly cycle** **[Male low FSH]: infertility, sexual dysfunction** - **[Target cells]: most cells of the body** - **Note that all of these zones sec...

ENDOCRINE SYSTEM ================ - **Note: Low FSH will cause low LH in the human body.** **[Female low FSH]: infertility, lack of monthly cycle** **[Male low FSH]: infertility, sexual dysfunction** - **[Target cells]: most cells of the body** - **Note that all of these zones secrete a corticosteroid: aldosterone, cortisol, DHEA** **[Renin] catalyzes the conversion of a blood protein [angiotensinogen] to [angiotensin I.]** **Angiotensin I circulates to the [lungs] where it is converted to [angiotensin II], which** **causes [vasoconstriction] and blood pressure [increases].** - **DHEA is the major secretory steroidal product of the [adrenal cortex] and is the most abundant [steroidal] hormone in the human body. Hgh is the most abundant [protein] hormone. DHEA can also be produced in the [gonads and brain.]** - **DHEA acts on androgen receptors and can convert to produce androgen testosterone and all 3 estrogens (estrone (menopause), estradiol (nonpregnant), estriol (pregnant). It is sometimes called the "Mother Hormone".** - **Estrogens are mainly produced by the ovaries and the placenta. Some estrogens are also produced in smaller amounts by other tissues such as the [liver](http://en.wikipedia.org/wiki/Liver), [adrenal glands](http://en.wikipedia.org/wiki/Adrenal_gland), and the [breasts](http://en.wikipedia.org/wiki/Breast). These secondary sources of estrogens are especially important in postmenopausal women. [Fat cells](http://en.wikipedia.org/wiki/Adipocyte) also produce estrogen, potentially being the reason why [underweight](http://en.wikipedia.org/wiki/Underweight) or [overweight](http://en.wikipedia.org/wiki/Overweight) persons are risk factors for [infertility](http://en.wikipedia.org/wiki/Infertility).** - **Don't forget about [renin] (enzyme) that interacts with [angiotensinogen].** - **The main enzyme that cleaves Angiotensin I to Angiotensin II is called [*Angiotensin-converting enzyme*](http://en.wikipedia.org/wiki/Angiotensin-converting_enzyme) (ACE, also** **[Leptin]** - **A [protein hormone] derived from [white adipose tissue] (receptors for leptin are on the [hypothalamus \[satiety center\])]** **[White fat vs. Brown fat:]** **- [ ] what the general public refers to as [adipose tissue]** **- functions as an [energy store] and [thermal regulator]** **- found in [large amounts] in [newborns] and [hibernating animals (specifically located on ]** **[the back and neck)]** **- found in [smaller amounts in adults]** **- functions as an [thermal regulator]** - **Leptin is a [protein] product of the [OB] (obesity gene)** - **Considered to be the [most important] adipose derived hormone** - **Leptin functions to increase satiety, decrease appetite and cause weight loss** - **The level of circulating leptin is directily proportional to the total amount of body fat** - **An [increase in food intake] triggers an [increase in leptin] response causing a [decrease in hunger]** - **Obese patients are usually [leptin resistant] (research shows the brain releases a chemical to resist leptin, therefore; leptin therapy does not work as treatment for obesity)** - **Leptin is responsible for [long term energy balance] (opposite of [ghrelin])** - **Leptin and insulin are being researched thoroughly in regard to treat type 2 diabetes or insulin resistance** **Ghrelin** - **Opposite of leptin; ghrelin is a [meal initiator] and [short term energy balance] hormone** - **Produced by the fundus of the stomach and epsilon cells of the pancreas** - **Ghrelin levels increase before meals and decrease after meals** - **Ghrelin stimulates [growth hormone] (secreted by [anterior pituitary gland])** - **Ghrelin receptors are on the [hypothalamus, pituitary gland and GI tract]** - **Name is derived from [growth hormone releasing peptide]** **(ghre- means [to grow], lin -- a usual suffix for some hormones)** - **Ghrelin does [not] contribute to obesity (because its [short term energy balance]); anorexics have been noted to have an [increased level] of ghrelin**