Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Mammary gland wikipedia , lookup
Xenoestrogen wikipedia , lookup
Triclocarban wikipedia , lookup
Neuroendocrine tumor wikipedia , lookup
Glycemic index wikipedia , lookup
Hyperthyroidism wikipedia , lookup
Growth hormone therapy wikipedia , lookup
Hypothalamus wikipedia , lookup
Hyperandrogenism wikipedia , lookup
The Endocrine System • Controls many body functions – exerts control by releasing special chemical substances into the blood called hormones – Hormones affect other endocrine glands or body systems • Derives its name from the fact that various glands release hormones directly into the blood, which in turn transports the hormones to target tissues via ducts. The Endocrine System • Exocrine glands transport their hormones to target tissues via ducts. • Endocrine Emergencies: – from common: • Diabetes • to the unusual: – Thyrotoxicosis The Endocrine System • Consists of several glands located in various parts of the body. • Pituitary gland: a small gland located on a stalk hanging from the base of the brain - AKA • “The Master Gland” – Primary function is to control other glands. – Produces many hormones. – Secretion is controlled by the hypothalamus in the base of the brain. The Endocrine System • The Pituitary Gland is divided into 2 areas, which differ – structurally and functionally – each area has separate types of hormone production. • The two segments are: – Posterior Pituitary: • produces oxytocin and antidiuretic hormone (ADH) – Anterior Pituitary: • produces thyroidstimulating hormone (TSH) • growth hormone (GH) • adrenocorticotropin (ACTH) • follicle-stimulating hormone (FSH) The Endocrine System • And even more… – luteinizing hormone (LH) – prolactin • Let’s go over these one at a time... • Posterior Pituitary – Oxytocin (the natural form of pitocin) • stimulates gravid uterus • causes “let down” of milk from the breast. – ADH (vasopressin) causes the kidney to retain water. The Endocrine System • Anterior Pituitary – Primarily regulates other endocrine glands – rarely a factor in endocrinological emergencies – TSH stimulates the thyroid gland to release its hormones, thus metabolic rate • Anterior Pituitary… – Growth hormone (GH) • glucose usage • consumption of fats as an energy source – ACTH stimulates the adrenal cortex to release its hormones – FSH & LH stimulates maturation & release of eggs from ovary. The Endocrine System • The Thyroid Gland – lies in the anterior neck just below the larynyx. – Two lobes, located on either side of the trachea, connected by a narrow band of tissue called the isthmus. – Sacs inside the gland contain colloid • Within the colloid are the thyroid hormones: – thyroxine (T4) – triiodothyronine (T3) • When stimulated (by TSH or by cold), these are released into the circulatory system and the metabolic rate. – “C” cells within the thyroid produce the hormone calcitonin. The Endocrine System • Calcitonin, when released, lowers the amount of calcium in the blood. • Inadequate levels of thyroid hormones = hypothyroidism, or Myxedema. • Myxedema symptoms: – Facial bloating – weakness – cold intolerance – lethargy – altered mental status – oily skin and hair – TX: replacement of thyroid hormone. The Endocrine System • Increased thyroid hormone release causes hyperthyroidism, commonly called Graves’ disease. – Signs and symptoms: • insomnia, fatigue • tachycardia • hypertension • heat intolerance • weight loss – Long term hyperthyroidism: • Exopthalmos – bulging of the eyeballs (picture Barbara Bush) • In severe cases - a medical emergency called thyrotoxicosis can result. The Endocrine System • Parathyroid Glands – small, pea-shaped glands, located in the neck near the thyroid – usually 4 - number can vary – regulate the level of calcium in the body – produce parathyroid hormone - level of calcium in blood – Hypocalcemia can result if parathyroids are removed or destroyed. The Endocrine System • Pancreas – a key gland located in the folds of the duodenum – has both endocrine and exocrine functions – secretes several key digestive enzymes • Islets of Langerhans – specialized tissues in which the endocrine functions of the pancreas occurs – include 3 types of cells: • alpha ( ) • beta () • delta () – each secretes an important hormone. The Endocrine System • Alpha () cells release glucagon, essential for controlling blood glucose levels. • When blood glucose levels fall, cells the amount of glucagon in the blood . • The surge of glucagon stimulates the liver to release glucose stores (from glycogen and additional storage sites). • Also, glucagon stimulates the liver to manufacture glucose • gluconeogenesis. The Endocrine System • Beta Cells () release insulin (antagonistic to glucagon). • Insulin the rate at which various body cells take up glucose. Thus, insulin lowers the blood glucose level. • Insulin is rapidly broken down by the liver and must be secreted constantly. • Delta Cells () produce somatostatin, which inhibits both glucagon and insulin. The Endocrine System • Adrenal Glands – 2 small glands that sit atop both kidneys. – Each has 2 divisions, each with different functions. • the Adrenal Medulla secretes the catecholamine hormones norepinephrine and epinephrine (closely related to the sympathetic component of the autonomic nervous system). The Endocrine System • One at a time… • The Adrenal Cortex secretes 3 classes of hormones, all steroid hormones: – gluticocorticoids mineralocorticoids – androgenic hormones – gluticocorticoids: – accounts for 95% of adrenal cortex hormone production – the level of glucose in the blood – Released in response to stress, injury, or serious infection - like the hormones from the adrenal medulla. The Endocrine System • Mineralocorticoids: – work to regulate the concentration of potassium and sodium in the body. • Prolonged in adrenal cortex hormone results in Cushing’s Disease. • Signs & Symptoms of Cushing’s Disease: – in blood sugar levels – unusual body fat distribution – rapid mood swings The Endocrine System • And - if there is an in mineralocorticoids as well – A serious electolyte imbalance will occur due to the potassium excretion by the kidney, which results in hypokalemia. • Sodium can also be retained by the kidney, resulting in hyponatremia. – Causes: • dysrhythmias • coma • death – usually results from a tumor - TX? Removal of tumor. The Endocrine System • Gonads and Ovaries: – the endocrine glands associated with human reproduction. – Female ovaries produce eggs – Male gonads produce sperm • both have endocrine functions. • Ovaries: – located in the abdominal cavity adjacent to the uterus. – Under the control of LH and FSH from the anterior pituitary they manufacture • estrogen • protesterone The Endocrine System • Estrogen and Progesterone have several functions, including sexual development and preparation of the uterus for implantation of the egg. • Testes: – located in the scrotum – produce sperm for reproduction – manufacture testosterone • promotes male growth and masculinization – Controlled by anterior pituitary hormones FSH and LH. The Endocrine System • Endocrine Emergencies: • Diabetes Mellitus – one of the most common diseases in North America. – insulin secretion by the Beta () cells of the islets of Langerhans in the pancreas. • Complications of Diabetes: – contributes to heart disease – stroke – kidney disease – blindness The Endocrine System • Pathophysiology of Diabetes: • Glucose Metabolism – Glucose (dextrose) is a simple sugar required by the body to produce energy. – Sugars, or carbohydrates, are 1 of 3 major food sources used by the body. • The other 2 major food sources are – proteins – fats • Most sugars in the human diet are complex and must be broken down into simple sugars: glucose, galactose and fructose - before use. The Endocrine System • Breakdown of sugars is carried out by enzymes in the gastro intestinal system. – As simple sugars, these are absorbed from the GE system into the body. – More than 95% enter the body as glucose. • To be converted into energy, glucose must first be transmitted through the cell membrane. BUT - the glucose molecule is large and doesn’t readily diffuse through the cell membrane. The Endocrine System • Glucose must pass into the cell by binding to a special carrier protein on the cell’s surface. – Facilitated diffusion doesn’t use energy. The carrier protein binds with the glucose and carries it into the cell. • The rate at which glucose can enter the cell is dependent upon insulin levels. – Insulin serves as the messenger - travels via blood to target tissues. – Combines with specific insulin receptors on the surface of the cell membrane.