Endocrine System Anatomy PDF

Endocrine System Anatomy What is the endocrine system? Systems made up of glands and organs and the hormones they secrete Besides glands, primary hormone producers, the brain, heart, lungs, liver, skin, thymus, gastrointestinal mucosa, and placenta also produce and release hormones Function- product...

Endocrine System Anatomy What is the endocrine system? Systems made up of glands and organs and the hormones they secrete Besides glands, primary hormone producers, the brain, heart, lungs, liver, skin, thymus, gastrointestinal mucosa, and placenta also produce and release hormones Function- production and regulation hormone-assisted organ function Primary Endocrine Glands Pituitary (the master gland) Pineal gland Thyroid Parathyroid Islets of Langerhans Adrenals Ovaries Testes Hormones Chemical transmitters released in small amounts from glands and organs and transported in the bloodstream to target organs or cells Transfer information and instructions Regulate growth, development, mood, tissue function, metabolism, and sexual function Endocrine system and nervous system work together to help maintain homeostasis of organ function The hypothalamus is the primary link between the two systems by way of the pituitary gland Pituitary Gland Adenohypophysis Secretions Growth Hormone (GH): Stimulates growth and development of bones, muscles Also enhances protein synthesis, decreases the use of glucose, and promotes fat destruction Adenohypophysis Secretions Adrenocorticotropin (ACTH) Hypothalamic-pituitary-thyroid axis Involved in mineralocorticoid, cortisol and androgen production Thyroid-Stimulating Hormone (TSH) It stimulates the production of the thyroid hormones, thyroxine (T4)and triiodothyronine (T3) by binding to its receptors Adenohypophysis Secretions Follicle-Stimulating Hormone (FSH): gonadotropic hormone It stimulates the growth ovarian follicles in the female (conversion to estrogen by granulosa cells and the production of sperm in the male (Sertoli cells) Adenohypophysis Secretions Luteinizing Hormone (LH): Stimulates steroid ovulation, and the release of progesterone after ovulation by the corpus luteum the production of testosterone in the male Adenohypophysis Secretions Prolactin (PRL): Stimulates the development and growth of the mammary glands and milk production during pregnancy Adenohypophysis Secretions Melanocyte-stimulating hormone (MSH): regulates skin pigmentation and promotes the deposit of melanin in the skin after exposure to sunlight Neurohypophysis Secretions Antidiuretic Hormone (ADH): Stimulates the reabsorption of water by the renal tubules Hyposecretion of this hormone can result in diabetes insipidus Neurohypophysis Secretions Oxytocin Stimulates the uterus to contract during labor, delivery, and parturition It also stimulates the mammary glands to release milk A synthetic version of this hormone, used to induce labor, is called Pitocin. Pineal Gland Endocrine gland located in the posterior aspect of the cranial fossa in the brain Pinecone-shaped and about 0.8 cm long Is in proximity with the thalamus, behind the third ventricle CSF bathes the gland through the pineal recess Secretes melatonin in response to darkness: Communicates information about environmental lighting Has effect on circadian cycle of sleep and wakefulness Thyroid Gland Plays a vital role in metabolism and regulates the body’s metabolic processes Thyroxine (T4) and triodothyronine (T3): essential to BMR Influences physical/mental development and growth Parathyroid Gland Two pairs of glands located on the dorsal of the thyroid gland They secrete parathyroid (PTH) which plays a role in the metabolism of phosphorus Too little secretion – hypocalcemia, hyperphosphatemia Too much secretion – hypercalcemia, hypophosphatemia The Islets of Langerhans Small clusters of cells located in the pancreas Alpha cells facilitate the breakdown of glycogen to glucose - elevates the blood sugar Beta cells secrete the hormone insulin, which is essential for the maintenance of normal blood sugar levels Delta cells suppress the release of glucagon and insulin. Adrenal Glands Located on the top of each kidney Cortex: Cortisol - regulates carbohydrate, protein, and fat metabolism; has an anti-inflammatory effect; helps the body cope during times of stress Aldosterone - essential in regulating electrolyte and water balance by promoting sodium and chloride retention and potassium excretion Androgens - several hormones including testosterone; they promote the development of secondary sex characteristics in the male Adrenal Glands Medulla Epinephrine - AKA is also called adrenalin Elevates systolic blood pressure Increases heart rate and cardiac output Speeds up the release of glucose from the liver Bronchodilation Dilates the pupils to see more clearly Norepinephrine Like epinephrine, is released when the body is under stress It creates the underlying influence in the fight or flight response Sex Hormones Ovaries Estrogen -Granulosa Cells (FSH) Testosterone – Theca Cells (LH) Progesterone – Corpus Luteum Testicles Testosterone - Leydig cells (LH) Thymus Has two lobes In the chest, between the lungs and behind the breastbone or sternum Part of the lymphatic system Is a ductless gland Secretes thymosin -. stimulates the development of precursor T cells in the thymus to mature T cells