Endocrine system.txt

second-messenger system of the body after the nervous system

• AMINO ACID Based: include proteins, peptides and amines
• STEROIDS: made from cholesterol

certain tissues or TARGET cells or TARGET organs

Specialized by the cells having specific protein RECEPTORS

• 1. DIRECT Gene activation: steroid hormone action, slower of the two
• 2. Second-messenger system: non-steroid hormone BINDS to a membrane receptor and gives off a message which activates an enzyme IN the cell

• All Non-steroid (proteins)
• GH - Growth Hormone: Stimulates GROWTH of muscle & bones. REGULATED by hypothalamic releasing & inhibiting hormones
• PRL - Prolactin: Stimulates MILK production. REGULATED by hypothalamic hormones

• All Non-steroid (proteins)
• FSH Follicle-stimulating hormone: Stimulates PRODUCTION of OVARIES and SPERM. REG by Hypothalamic hormones
• LH - Luteinizing hormone: Stimulates OVULATION of eggs (females) and TESTOSTERONE (males). REG by Hypothalamic hormones
• TSH - Thyroid Stimulating Hormone: stimulates Thyroid Gland growth and activity. REG by Thyroxine in blood. REG by Hypothalamic hormones
• ACTH - Adrenocorticotropic hormone: Stimulates ADRENAL Cortex to Secrete GLUCOCORTICOIDS. REG by Glucocorticoids & Hypothalamic hormones

• Oxytocin: non-steroid (peptide), stimulates CONTRACTION of uterus and breast milk. REGULATED by nervous System (hypothalamus)
• Antidiuretic Hormone (aka vasopressin): non-steroid (peptide), promotes H20 RETENTION by kidneys...can cause INCREASE IN BP from vasoconstriction. REGULATED by hypothalamus in response to SALT imbalance

• 2 iodine-containing hormones: T3 (triiodothyronine)- converts to T4 @ target tissues. T4 (thyroxine)- secreted by thryroid follicles
• T3/T4: non-steroid (amine). Stimulates METABOLISM. REG by TSH
• Calcitonin: non-steroid (peptide). Stimulates OSTEOBLAST activity, LOWERING blood Ca levels. REG by Ca levels in blood.

• GOITERS: Thyroid Gland ENLARGES (swollen neck) from Lack of IODINE
• CRETINISM: Due to HYPOsecretion of T4 (thryoxine) resulting in DWARFISM during childhood
• MYXEDEMA: Due to HYPOthyroidism in adults..results in physical & mental SLUGISHNESS
• GRAVE's DISEASE: Caused by HYPERThyroidism..results in INCREASED metabolism, heat intolerance, rapid heart beat, exophthalmos

PTH - Parathyroid hormone: non-steroid (peptide). Stimulates OSTEOCLAST activity to RAISE blood Ca levels; stimulates kidneys & intestines to ABSORB more Ca. REG by Ca levels in blood.

• Hormones produced: Oxytocin & ADH...to be released by the Post Pituitary
• Releasing and inhibiting hormones that REGULATE the anterior Pituitary

Thymosin: non-steroid (peptide). Produces types of WBC's, develops immune system by programming T lymphocytes

• Insulin: non-steroid (protein). Work to lower blood glucose levels by allowing glucose to CROSS PLASMA membrane into cells from BETA cells. REG by blood glucose levels
• Glucagon: non-steroid (protein). Work to Raise blood glucose levels by allowing glucose to ENTER blood from ALPHA cells. REG by blood glucose levels

Norepi & Epinephrine(adrenaline): non-steroid (amines). Raise Blood glucose level, INCREASE metabolism, Constrict blood vessels, Dialate lung passageways. REG by Sympathetic nervous system

• Glucocorticoids: STEROID hormones. Stimulated by INCREASED blood glucose. REG by ACTH (tropic hormone)
• Mineralocorticoids: STEROID hormones. Promote REABSORPTION of Na and EXCRETION of K in kidneys. REG by changes in blood pressure/volume/Na & K levels

• Addison's disease: weak muscles and Bronze skin tone from lack of hormones
• Hyperaldosteronism: can be due to ACTH-releasing TUMOR. Excess water & Na retained..lead to High BP & Edema
• Cushing's syndrome: from tumor in middle area of cortex. 'Moonface,' 'buffalo hump' on upper back, High BP, hyperglycemia, weakening of bones, depression

• Mainly consist of ALDOSTERONE, goal to REGULATE mineral content in blood
• REGULATES water & electrolyte balance

• Cortisol & Cortisone: released in response to INCREASED blood levels of ACTH (ACTH stimulates release of these glucocorticoids)
• Produces in Middle layer of cortex
• Aids with Normal cell metabolism
• Aids in resisting long term stressors

• All these gonadotropic hormones are REG by FSH and LH (in Ant pituitary) by NEGATIVE feedback
• Testes: Produce sperm & secrete ANDROGENS (STEROID hormones)such as testosterone. Support SPERM formation and Devel. of 2ndary SEX characteristics
• Ovaries: Produces eggs & secretes ESTROGENS and PROGESTERONES (STEROID Hormones).
• Est & Progest Stimulate growth of UTERINE lining. PROGEST gets breasts ready for LACTATION & helps implant EMBRYO in uterus. ESTROGEN involved in development of 2ndary SEX characteristics (breast), regulates menstrual cycle.

• Gonad hormones in testes (androgens) & ovaries (estrogen & progesterone) & Adrenal Cortex hormones (Glucocorticoids & Mineralcorticoids) are the only STEROID hormones.
• Everything else is non-steroid

• Hangs by a stalk from the HYPOTHALAMUS in brain
• ANTERIOR pit: composed of GLANDULAR tissue
• POSTERIOR pit: composed of NERVOUS tissue
• Often called the 'master endocrine' gland

• Mostly are regulated by negative feedback
• Since all are non-steroid (proteins), act through Second Messenger Systems

• Metabolic Hormone
• Effects related to growth of muscle and long bones
• Causes AA's to be built into PRoteins
• Causes fats to be broken down as ENergy source

• Pituitary Dwarfism: hyposecretion of GH during childhood
• Gigantism: hypersecretion of GH during childhood (does not include enlarged organs, so organs can fail due to the increased stress put upon them)

• On 3rd ventricle of brain
• Secretes MELATONIN
• Helps establish the body's SLEEP & Wake cycle