Chapter 38 Endocrine System.pptx

Endocrine System What is the Endocrine System? + Consists of glands located all throughout the body that secrete various hormones + Hormones produced are secreted help maintain homeostasis within the body • Fluid balance • Metabolism, energy balance • Contraction of smooth and cardiac muscle • G...

Endocrine System What is the Endocrine System? + Consists of glands located all throughout the body that secrete various hormones + Hormones produced are secreted help maintain homeostasis within the body • Fluid balance • Metabolism, energy balance • Contraction of smooth and cardiac muscle • Growth and development • Reproduction • Circadian rhythms • And more! Hormones & Receptors + Hormones flow through capillaries Travel everywhere in body + “Lock & Key” system used when hormone needed Hormone – Key Target Cell (Receptor Site) – Lock + Receptor site is specific for one hormone Negative Feedback System/Mechanism + Most common type of endocrine feedback system + These systems reverse changes that occurred in the controlled condition + Results in the gland increasing or decreasing the release of a hormone + Hormone secretion usually depends on the body’s need for the final action of the hormone 1. Body condition moves away from normal range 2. Specific hormone stimulated -> starts chain of events to return body to normal 3. Once need is met and body condition normalized, secretion of the hormone will cease Negative Feedback Glands of the Endocrine System • Glands of the Endocrine System: • Pineal Gland • Hypothalamus • Pituitary Gland • Anterior • Posterior • Thyroid Gland • Parathyroid Gland • Thymus • Adrenal Glands (2) • Pancreas • Ovaries (Female) • Testes (Male) • Bolded = covered in this lecture Hypothalamus + Produces regulatory hormones, which are either: • Releasing hormones • Inhibiting hormones + Function of regulatory hormones is to stimulate or inhibit the release of hormones from the anterior pituitary gland + The hypothalamus is also responsible for synthesizing the following hormones: • Oxytocin • Antidiuretic Hormone (ADH) These hormones are stored and released from the Posterior Pituitary Gland Anterior Pituitary Gland + Regulated by hypothalamus by inhibiting or releasing hormones + Contains tropic hormones Hormones that send messages to other endocrine glands to release their hormones • Thyroid Stimulating Hormone (TSH)  thyroid • Adrenocorticotropic Hormone (ACTH)  adrenal glands • Follicle-Stimulating Hormone (FSH)  Ovary/Testis • Luteinizing Hormone (LH)  Ovary/Testis + Other two hormones in this gland act directly on final target tissues • Growth Hormone  body tissues • Prolactin  mammary gland Posterior Pituitary Gland + Extension of the hypothalamus + Does not synthesize hormones Hormones produced in the hypothalamus The posterior pituitary gland stores and releases hormones + Antidiuretic Hormone (ADH) aka vasopressin + Oxytocin Anterior Pituitary Gland FSH LH ACTH TSH Prolactin (Ignore) GH Anterior Pituitary Posterior Pituitary Hormones Hormone Target Organs Effects TSH (thyroid stimulating hormone) Thyroid Gland Stimulates thyroid gland to secrete thyroid hormones ACTH (adrenocorticotropic hormone) Adrenal Gland (Cortex) Stimulates adrenal cortex to secrete glucocorticoids (cortisol) FSH (follicle-stimulating hormone) Ovary and Testis Stimulates secretion of estrogen and the development of ova in women and sperm development in men (control of reproductive function) LH (luteinizing hormone) Ovary and Testis Stimulates ovulation in women and secretion of sex hormones in both men and women (control of reproductive function) GH (growth hormone) Liver, Adipose Tissue Promotes growth (indirectly) Prolactin Mammary Gland Stimulates breast development necessary for lactation after child birth (milk production) ADH (antidiuretic hormone or vasopressin) Kidney Regulates fluid volume by stimulating reabsorption of water in the kidneys (conservation of water in body) Oxytocin Ovary and Testis Stimulates ejection of milk into mammary ducts and uterine contractions Thyroid Gland + Anterior to the trachea, consists of two lobes + Produces three hormones: • Triiodothyronine (T3) • Thyroxine (T4) • Calcitonin + The thyroid gland is the only gland of the endocrine system that can be palpated, however it can not always be felt + If a patient has a suspected thyroid issue, the provider must take precaution when palpating because it can release additional hormones & exacerbate symptoms Thyroid Gland Hormones Thyroid hormones are essential for life! Essential for physical growth, mental development, & reproductive maturation + Thyroid hormones (T3 & T4) essential for metabolic activity These hormones increase the metabolic rate of the body; utilizing energy and producing heat + Example: in cold temperatures, more thyroid hormones released to increase heat production In order for the body to produce T3 & T4, there must be sufficient intake of protein & iodine + Calcitonin is released when serum calcium levels are too high Inhibits breaking down bones for calcium and phosphate + Keeps calcium from leaving the bones + Decreases resorption of calcium in the kidneys Lowers serum levels of calcium Thyroid Palpation + The thyroid gland is the only gland of the endocrine system that can be palpated Usually palpated by a NP or physician Nurse may assist with positioning, giving patient sip of water + If a patient has a suspected thyroid issue, the provider must take extra precaution when palpating because it can release additional hormone & exacerbate symptoms Parathyroid Gland + Four glands that sit on the thyroid gland + Produce parathyroid hormone (PTH) + Parathyroid hormone raises serum calcium levels & lowers phosphate levels • Pulls calcium that is stored in bones • Encourages the small intestine to absorb more calcium • Encourages the kidneys to reabsorb more calcium • Remember, calcium is key for neuron & muscle cell excitability + Target organs of PTH include: Bones Small intestine Kidneys Adrenal Glands + The adrenal glands sit on top of the kidneys + Consists of two sections: Adrenal Medulla Adrenal Cortex + Releases epinephrine & norepinephrine Adrenal Medulla When released from adrenal medulla, these catecholamines act as hormones, not neurotransmitters + Hormones released during stress to manage the body’s stress response Cause SNS response + Increased cardiac contractions, Increased cardiac output, Increased HR + Peripheral artery constriction  Increased BP + Bronchodilation + Skeletal muscle arterioles dilate  enhanced blood flow to muscles + Increased glucose availability (glycogen  glucose) Adrenal Cortex + Three hormones produced and secreted from this gland All classified as corticosteroids 1. Mineralocorticoids (Aldosterone) Acts on kidneys to conserve sodium and fluid follows Acts on kidneys to rid the body of potassium Increased serum sodium, decreased serum potassium, increased fluid volume, increased blood pressure 2. Glucocorticoids (Cortisol) Provides energy sources to the body & ensures glucose is made available for the brain + Acts on liver to convert glycogen to glucose Released during body’s response to stress – the body requires more energy for stress induced changes + When the body is stressed, the Hypothalamus tells the Anterior Pituitary Gland to release ACTH + ACTH then travels to the adrenal cortex and stimulates release of cortisol 3. Gonadocorticoids (Androgens) Contribute to libido Adrenal Gland Mnemonics Adrenal Medulla Adrenal Cortex MNEMONIC: “MAKE GOOD SWEETS” Saying: “Salt, Sex & Sugar” • Mineralocorticoids • Glucocorticoids • Sex hormone MNEMONIC: “MEN” •Medulla •Epinephrine •Norepinephrine Pancreas + Both an endocrine gland and an exocrine gland Exocrine gland function includes release of amylase & lipase for digestion assistance As endocrine gland, the pancreas secretes insulin and glucagon for glucose homeostasis + Cells within the pancreas include: Alpha Cells: Secretes Glucagon Beta Cells: Secretes Insulin These cells live within a section of the pancreas called the “islet of Langerhans” Pancreas + Insulin Released by the pancreas when serum glucose levels rise Insulin is the key to unlock the cells, once unlocked glucose can travel inside the cells & be used for energy Without insulin, the cells will starve because they cannot metabolize glucose + Serum glucose levels continue to rise in this case + Glucagon Released by the pancreas when serum glucose levels are low Glucagon stimulates the liver to turn glycogen to glucose Glucagon is imperative to combat hypoglycemia + Hypoglycemia leads to brain death! Endocrine Disorders Causes: Primary Disorder Secondary Disorder • Overproduction of the hormone • Underproduction of the hormone • Side effects of certain drugs • Something wrong with the gland itself • Something wrong with a different gland/organ  affects endocrine gland Effects of Aging on the Endocrine System