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Transcript
Endocrine and Lymphatic/ Immune Systems Endocrine System – works with the Nervous System to coordinate and integrate the activity of body cells Endocrinology • • • • • Endo = inside or within Crine = Secrete Ology = study of Hormon – to excite Definition = Study of hormones and how they work in the body • Hormone – a mediator molecule that gets released in one part of the body but regulates the activity of cells in other parts of the body Functions • Work with Nervous System to coordinate body functions • Maintain homeostasis within the body Hormone Facts • Two types of glands in the body – Exocrine • Secretes products to outside of body – Endocrine • Ductless glands and make hormones • Secrete products inside the body • Organs – Hypothalamus, thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small intestine, skin, heart, adipose tissue, placenta Hormone Travels • Circulating Hormones – True Hormones – Affect specific target cells – Stay in the blood stream • Local Hormones - Pseudohormones – Act on neighboring cells – Do not enter the blood stream • Paracrine – act locally, but affect cell types other than those releasing them – Somatostatin – secreted by the pancreas – stops the release of insulin • Autocrine – chemicals that exert their effects on the same cells that secrete them – Prostaglandins - released by smooth muscle cells to make the smooth muscles contract Hormone Interactions • Permissiveness - When one hormone cannot exert its full effects without another hormone being present • Reproductive hormones develop the reproductive system (estrogen, testosterone, LH, FSH), but those do not start working unless the Thyroid hormone is released • Synergism - More than one hormone produces the same effects at the target cell and their combined effects are amplified • Glucagon and epinephrine cause the liver to release glucose in the blood – when they act simultaneously, they release about 150% more than what they would by themselves • Antagonism - When one hormone opposes the action of another hormone • Ex Insulin lowers blood glucose levels; it is antagonized by glucagon which raises blood glucose levels Chemical Classes of Hormones • Lipid-soluble hormones – Dissolve in fats • Water-soluble hormones – Dissolve in water Lipid-Soluble Hormones • Steroids – Derived from cholesterol – Cortisol, Estrogen, Testosterone, Aldosterone, Androgens, Calcitriol, Progesterone • Thyroid Hormones – T3 and T4 • Nitric Oxide – Hormone and neurotransmitter Water-Soluble Hormones • Amines – made by modifying amino acids – Epinephrine and norepinephrine, melatonin, histamine, serotonin • Peptide Hormones – chains of amino acids – Antidiuretic hormone, oxytocin, HGH, Thyroid-stimulating hormone, adrenocorticotropic hormone, FSH, LH, Prolactin, melanocyte-stimulating hormone, insulin, glucagon, somatostatin, parathyroid hormone, calcitonin, gastrin, secretin, cholecystokinin, erythropoietin, leptin • Protein Hormones – more complex chains of amino acids – subtype of peptide hormones • Eicosanoid – derived from a 20-carbon fatty acid – Prostaglandins – Leukotriens How Hormones work • Lipid-Soluble – diffuse through the lipid bilayer of the plasma membrane and bind to receptors within target cells • Water-Soluble – cannot diffuse through the membrane – Bind to Integral Proteins on the membrane surface Control of Hormone Secretion • Hormones are secreted in short bursts • Regulated by – Signals from NS • Hypothalamus signals the Pituitary Gland to make and realease hormones • Hypothalamus secretes 9 hormones • Pituitary Gland secretes 71q – Chemical changes in the blood – Other hormones Hypothalamus and Pituitary Gland • Hypothalamus is the “Master” of the Pituitary Gland – Major link between the NS and ES – Secretes 9 hormones • Pituitary Gland – Secretes 7 hormones – Two Lobes: Anterior and Posterior – Rests in the Sella Turcica • Hypothalamus and Pituitary Gland are connected by the INFUNDIBULUM Anterior Pituitary Gland • Releases tropic hormones which influences other endocrine glands • Regulated by Releasing and Inhibiting Hormones Anterior Pituitary Hormones • Human Growth Hormone (HGH) – Most plentiful Ant. Pituitary Hormone • Gigantism – too much HGH – typically reach 8ft • Pituitary Dwarfism – too little HGH – 4ft. or under, body is properly proportioned • Thyroid-Stimulating Hormone – Stimulates Thyroid gland to make and secrete Thyroid Hormone which has 2 forms: T3 and T4 m • Invtrsdrd nsdsl mrysnoliv tsyr snf nofy hrsy ptofuvyion – Released in response from TRH hormone of the Hypothalamus Thyroid Problems • Hypothyroidism – Underactive thyroid gland • Adults - Myxedema – low metabolism, cold, constipation, thick/ dry skin, puffy eyes, edema, lethargy and mental sluggishness – If myxedema is from a lack of Iodine, the thyroid gland can enlarge and protrude and become an endemic goiter – Why salt is now IODIZED; Goiter Belt • Infants – Cretinism – mental retardation, disproportionate body size, thick tongue and neck – might be a genetic defect of fetal thyroid or a lack of iodine in mother’s diet – Can be prevented by hormone replacement therapy if diagnosed early enough » Most states test newborns to check for hypothyroidism at birth Thyroid Problems • Hyperthyroidism – overactive thyroid – Grave’s Disease – believed to be autoimmune because people who have this disease have abnormal antibodies that mimic TSH and will stimulate the release of TH • Increased metabolism, sweating, irregular/ rapid heart beat, nervousness, weight loss • Signs – enlarged thyroid (goiter), exophthalmos • Treatment – Thyroidectomy or treatment with Radioactive Iodine which will destroy most of the active thyroid cells Parathyroid Hormone • Controls calcium balance within the blood • Hyperparathyroidism – rare, usually happens because of a tumor – Ca gets leached from the bones – bones will soften and deform as their mineral salts are replaced by fibrous CT – high blood Ca can suppress the nervous system and cause kidney stoes Parathyroid Hormone • Hypoparathyroidism – Usually after some type of parathyroid trauma or removal during thyroid surgery, extended lack of dietary Mg • Hypocalcemia – tetany (loss of sensation, muscle twitches, convulsions) • Untreated – symptoms progress to respiratory paralysis and death • Was how the Parathyroid gland was discovered Anterior Pituitary Hormones • Follicle-Stimulating Hormone – Hypothalamus – Anterior Pituitary – Testes, Ovaries – Stimulates production of sperm and maturing of follicles (eggs) • Luteinizing Hormone – Controlled by the hypothalamus – Stimulates secretion of estrogen and progesterone and ovulation in females; in males it stimulates the release of testosterone Anterior Pituitary Hormones • Adrenocorticotropic Hormone (ACTH) – Influences glucose metabolism • Prolactin – Hypothalamus secretes Releasing and Inhibiting Hormones to control Prolactin – Makes the body recognize a pregnancy – Stimulate milk production in women Posterior Pituitary Gland • Does not make hormones – Stores and releases them Posterior Pituitary Hormones • Oxytocin – Enhances muscle contraction during childbirth – After childbirth – stimulates milk production and delivery of the placenta – Pitocin to induce labor – synthetic verson • Antidiuretic Hormone or Vasopressin – Diabetes Insipidus – excessive urine and intense thirst – results in fluid retention, headache, disorientation Cushing’s Syndrome • • • • • • • Excessive Cortisol in the blood stream Persistent hyperglycemia Loss in muscle and bone protein Water and salt retention Swollen “moon” face Redistribution of fat – buffalo hump Ease in bruising Hypoglycemia – low blood glucose • Stimulates the hypothalamus to release GHRH (growthhormone-relasing-hormone) and GHRH goes to the Anterior Pituitary • Anterior Pituitary is then stimulated to release HGH into the blood stream • HGH – stimulates the release of insulin-like growth factors that speed up the breakdown of liver glycogen into glucose • As a result, blood glucose rises to the normal level (90mg/100mL of blood plasma) • An increase in blood glucose above the normal level inhibits (stops) the release of GHRH NEGATIVE FEEDBACK Hyperglycemia – abnormally high blood glucose • Stimulates the hypothalamus to secrete GHIH (Growthhormone-inhibiting-hormone) while inhibiting the release of GHRH • GHIH travels to the Anterior Pituitary and prevents it from releasing Growth Hormone • Low levels of GH in the blood stream and IGFs slows down the breakdown of glycogen in the liver and glucose is released into the bloodstream more SLOWLY • Blood glucose falls to its normal level • A decrease in the blood glucose below the normal level inhibits the release of GHIH NEGATIVE FEEDBACK Congenital Adrenal Hyperplasia • Genetic disorder in which a person lacks the enzymes needed to make Cortisol • If there is low or no cortisol, another hormone (ACTH) stimulates enlargement of the adrenal glands • Causes Virilism – Females – masculinization – growth of a beard, deep voice, body hair similar to male, growth of clitoris to resemble a penis, loss of breasts – Males – same as females – over-masculinization Addison’s Disease • Cause – ACTH is blocked from it’s receptors • Symptoms – lethargy, anorexia, nausea, vomiting, weight loss, hypoglycemia, weakness, bronzed appearance to skin • Treatment – hormone replacement and increasing sodium in diet • JFK had this Diabetes • Diabetes Mellitus (mell = honey sweetened) – – – – Inability to produce insulin 4th leading cause of death in the US Causes glucosuria (excessive glucose in the urine) Key defining symptoms • Polyuria – excessive urine production due to an inability of the kidneys to resabsorb water • Polydipsia – excessive thirst • Polyphagia – excessive eating – Genetic and Environmental components – 2 types – Type I and Type II Type I Diabetes – Insulin-dependent Diabetes Mellitus • Insulin level is low because the person’s immune system destroys the pancreatic beta cells that make the insulin • People with this must have daily doses of insulin to prevent death • Develops in people younger than age 20 • If not treated properly can lead to blindness and kidney disease Type II Diabetes – Non-insulin-dependent Diabetes Mellitus • Most common, 90% of all cases of diabetes • Typically found in obese people over age 35 • Can be controlled through diet, exercise and weight loss – Can be temporary • No shortage of insulin, rather the target cells become less sensitive to it Gestational Diabetes • Occurs in pregnant women who may or may not have had diabetes before the pregnancy • Pregnancy hormones block mom’s insulin receptors from being able to absorb insulin • Glucose can’t get absorbed properly so it is transferred to the baby – Baby grows more than it should – can lead to marcosomia (fat baby) – Concerns for during and after birth • Goes away immediately after giving birth