Endocrine System Organs and Disorders Endocrine versus Exocrine

Endocrine System Organs and Disorders

Endocrine versus Exocrine glands n Endocrine –ductless, releases hormones into intercellular space such as the blood stream q n Hypothalamus, pituitary gland Exocrine –releases contents into ducts or outside body q Ex. Sweat glands, sebaceous glands

Steroid versus protein hormone n Steroid –hormone that is lipid soluble, does through cell membrane of target organ to nucleus. n Protein (non-steroid) – hormone that needs a 2 nd messenger to send message to nucleus since it can not go through cell membrane on its own.

Protein Hormone Steroid Hormone

Homeostasis

n Prostaglandin –tissue hormones – produced in tissue and only travels short distance n Hormone – chemical messenger released by gland travels to target organ via the blood n Tropic Hormone – hormone that stimulates another endocrine gland to secrete hormones Ex. TSH, FSH n

Pituitary Gland n n Lies deep in brain, attached to hypothalmus Anterior pituitary – adenohypophysis (gland) q Tropic hormones – stimulates another endocrine gland to secrete hormone n n q q Thyroid stimulating hormone (TSH)– thyroid Adrenocorticotropic hormone –(ACTH) adrenal cortex Follicle-stimulating hormone (FSH) – ovarian follicles Luteinizing Hormone (LH)- ovulating hormone Growth hormone – promotes normal growth Prolactin – lactogenic hormone (breast development for lactation)

Disorders of AP n Growth hormone q Hypersecretion – gigantism, Acromegaly, hyperglycemia q n Hyposecretion – dwarfism Prolactin q q Hyper – inappropriate lactation in men and nonnursing women Hypo – insufficient lactation in nursing women

Posterior pituitary n n Antidiuretic hormone (ADH) – reabsorption of water from urine in kidney to blood, decrease urine volume Oxytocin – stimulates contraction of smooth muscle of uterus, initiate and maintain labor, stimulates milk letdown

Disorders of PP n ADH q q n Hyper – abnormal water retention Hypo – diabetes insipidus – elimination of too much urine – dehydration Oxytocin q q Hyper – increase milk flow Hypo – prolonged labor

Hypothalmus n n n Produces ADH and oxytocin (PP only releases them) Releasing hormones – stimulates Anterior pituitary to release hormones Inhibiting hormones – Inhibits anterior pit. release of hormones Hypothalmus functions in nervous and endocrine systems – dominant role in regulation of many body functions: body temp, appetite, thirst

Thyroid n n Thyroxine (T 4) and Triiodothyronine (T 3) – speed up cells release of energy from foods, stimulate cellular metabolism Calcitonin – maintains homeostasis of blood calcium, decreases the amount of calcium in the blood, act on bone to inhibit its breakdown, therefore calcium does not move out of bone.

Thyroid disorders n Hyperthyroidism, increase metabolic rate, lose weight, restless, excessively active n n n Exophthalmus – protruding eyes Graves disease – inherited, hyperthyroidism, bulging eyes Hypothyroidism – under secretion of TH q q q Goiter – low intake of iodine, enlargement of thyroid to compensate for lack of iodine Cretinism – low metabolic rate, retarded growth and sexual development Myxedema – lessened mental and physical vigor, weight gain, loss of hair, accumulation of mucous fluid (eyes)

Parathyroid glands n n Posterior of thyroid, Usually 4, small parathyroid hormone – increase concentration of calcium in blood (opposite of calcitonin) fig. 11 -12 Hyper – hypercalcemia Hypo - hypocalcemia

Adrenal Glands – top of kidneys n Adrenal cortex – outer part, corticoids q Mineralocorticoids, MC’s – aldosterone n q Glucocorticoids (cortisol, hydrocortisone) n q Control mineral salts in blood (increase sodium, decrease potassium) Maintain normal glucose concentration and blood pressure Sex hormones

Adrenal Medulla n n Inner portion of adrenal gland Epinephrine, Norepinephrine – secreted during stressful situations, works with sympathetic nervous system (adrenaline)

Adrenal disorders n Hypersecretion of GC’s – usually because of a tumor – Cushing syndrome q n Hypersecretion in inner zone – sex hormones called androgens, results in secondary sex characteristics q n Moon face, buffalo bump due to redistribution of body fat, can remove tumor In women, caused by virilizing tumor Hyposecretion of adrenal cortex - Addison disease – muscle weakness, low blood sugar

Pancreatic islets – islets of Langerhans n n n Scattered among pancreatic cells in pancreas Glucagon – increases the blood glucose concentration Insulin – decreases blood glucose concentration by moving it out of the blood q q Hypersecretion - hypoglycemia Hyposecretion - type 1 diabetes mellitus – high glucose levels in blood n Type 2 diabetes – abnormality of insulin receptors

Additional endocrine glands n Ovary q q n Testes q n Ovarian follicles – estrogen, feminizing hormone Corpus luteum – progesterone Testosterone – masculinizing hormone Thymus – in mediastinum, contains WBC’s q Thymosin – several hormones that play in important role in the development and function of the body’s immune system

More endocrine glands… n Placenta – temporarily produce hormones q n Chorionic ganadotropins (pregnancy test indicators), estrogen, progesterone Pineal gland – near 3 rd ventricle in brain q Melatonin – regulates puberty and menstrual cycle in females n n 3 rd eye – optic nerve, increase at night, internal clock and sleep cycle, supplements help to sleep SAD – seasonal affective disorder – high levels