Oh, the Secretions I’ll Learn! The Endocrine Glands and Their Hormones Anatomy Chapter 11

The Pituitary Gland

found at base of brain (sella turcica) 2 endocrine glands in one! attached to hypothalamus by stalk once considered master gland, but is known to be controlled by hypothalamus

Posterior Pituitary Gland aka neurohypophoysis (neuro=nerve) composed of nerve cells/fibers & neuroglia 2 hormones: 1. antidiuretic hormone-ADH- accelerates re-absorption of water from urine in kidneys decreases volume of urine released 2. oxytocin- secreted by females before and after birth of child

Anterior Pituitary Gland aka adenohypophysis (adeno=gland) 6-7 hormones many of these hormones will stimulate another endocrine gland to grow & secrete its hormones (tropic hormones) will affect: thyroid, adrenal cortex, ovarian follicles, corpus luteum

Tropic Hormones 1. thyroid stimulating hormone -TSH- acts on thyroid causes it to secrete thyroid hormone 2. adrencorticotropic hormone –ACTh- acts on adrenal cortex causes it to grow & secrete its hormones

3. follicle-stimulating hormone-FSH- stimulates follicles to start to grow causes them to secrete estrogen (females) (in males) stimulates cells to grow and form sperm

4. luteinizing hormone-LH- aka ovulating hormone stimulates follicles & ovum to grow & mature releases estrogen causes ovulation (females) produces progesterone (males) testes develop; secrete testosterone

Non-tropic Hormones 5. growth hormone –GH- stimulates cells to increase in size & divide frequently promotes normal growth has to be balanced with blood glucose level

Gigantism

Classic Acromegaly

Acromegaly

Dwarfism

6. melanocyte-stimulating hormone-MSH causes synthesis & dispersion of melanin by melanocytes may regulate ACTh 7. prolactin- stimulates milk production after birth found in males, but purpose not known

Thyroid Gland

below larynx & on sides & front of trachea Thyroid Gland vascular below larynx & on sides & front of trachea hypothalamus & pituitary gland controls 2 hormones released

thyroxine aka tetraiodothyronine, T4 (contains 4 iodine atoms) 2. triiodothyronine, T3 (contains 3 iodine atoms) most potent & principle hormone (5x stronger)

regulate metabolism of carbs, lipids, proteins by: purposes: regulate metabolism of carbs, lipids, proteins by: increasing rate which cells release energy from carbs incr rate of protein synthesis stimulate breakdown & mobilization of lipids

basal metabolic rate (BMR) the amount of calories the body must consume to maintain life at rest required for normal growth/development required for nervous sys to mature MUST have iodine *unique thyroid only gland to store hormones insufficient iodine = goiter

calcitonin- not actually considered true hormone regulates conc of bld calcium & phosphate ions the conc of calcium is what regulates release of calcitonin

Parathyroid Glands found on posterior of thyroid gland 4 glands composed of secretory cells covered in connective tissue

secrete parathyroid hormone –PTH- increases blood calcium concentration and decreases blood phosphate conc affects bones, kidneys, intestines increases a below normal bld calcium conc

Adrenal Glands found atop kidney (cap) vascular consists of 2 glands in one each releases different hormones

adrenal medulla composed of nerve cells cells connected with sympathetic nervous system hormones NOT VITAL for life secretes 2 hormones: epinephrine (adrenalin) norepinephrine (noradrenalin)

epinephrine makes up 80% of secretions both hormones have same effects as nerves on cell but lasts 10x longer hypothalamus responds to stress, sends impulses to a.m. body prepares for “fight or flight”

adrenal cortex makes up bulk of adrenal gland composed of epithelial cells vascular produces > 30 steroids many VITAL to life 3 main hormones:

1. aldosterone type of mineralocorticoid helps regulate conc of mineral electrolytes affects kidneys to conserve Na+ and excrete K+ stimulates water retention conc levels of Na+, K+, or kidney will affect hormone’s release

2. cortisol aka-hydrocortisone type of glucocorticoid- affects glucose metabolism, and metabolism of fats and proteins actions of hormone help blood glucose levels to stay within normal range between meals

3. adrenal sex hormones most male hormones (androgens), but changed to female hormones stimulates early development of reproduction organs

Cushing’s disease

Pancreas 2 glands in one! 2 major secretory cells exocrine portion secretes digestive enzymes endocrine releases hormones endo cells are grouped in clusters called: islets

islets contain 2 types cells: alpha – secrete hormone glucagon beta- secrete hormone insulin

glucagon – stimulates liver to breakdown glycogen into glucose raises blood sugar level prevents hypoglycemia when glucose conc is low or used rapidly

insulin- stimulates liver to form glycogen from glucose & inhibits conversion of noncarbs into glucose *only hormone to decrease blood sugar levels normal bld sugar level 80-120mg

too little insulin-type I diabetes abnormality of insulin type II diabetes

Pineal Gland aka - third eye near thalamus secretes melatonin which regulates circadian rhythms- patterns of repeated activity associated with cycles of day and night

helps body tell difference between day and night may control onset of puberty resembles pine cone

Thymus Gland