The Endocrine Glands and Their Hormones

Anatomy Chapter 11

Oh, the Secretions I’ll Learn!

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

aka neurohypophoysis (neuro=nerve)composed of nerve cells/fibers & neuroglia

2 hormones:1. antidiuretic hormone-ADH- accelerates re-

absorption of water from urine in kidneysdecreases volume of urine released

2. oxytocin- secreted by females before and after birth of child

Posterior 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

Anterior Pituitary Gland

1. thyroid stimulating hormone -TSH-acts on thyroidcauses it to secrete thyroid hormone

2. adrencorticotropic hormone –ACTh-acts on adrenal cortexcauses it to grow & secrete its hormones

Tropic Hormones

3. follicle-stimulating hormone-FSH-stimulates follicles to start to growcauses them to secrete estrogen (females)

(in males) stimulates cells to grow and form sperm

4. luteinizing hormone-LH-aka ovulating hormonestimulates follicles & ovum to grow & maturereleases estrogencauses ovulation(females) produces progesterone(males) testes develop; secrete testosterone

5. growth hormone –GH-stimulates cells to increase in size & divide frequentlypromotes normal growthhas to be balanced with blood glucose level

Non-tropic Hormones

Gigantism

Classic Acromegaly

Acromegaly

Dwarfism

6. melanocyte-stimulating hormone-MSH

causes synthesis & dispersion of melanin by melanocytesmay regulate ACTh

7. prolactin- stimulates milk production after birth

found in males, but purpose not known

Thyroid Gland

vascular below larynx & on sides & front of trachea

hypothalamus & pituitary gland controls

2 hormones released

Thyroid Gland

1. thyroxine aka tetraiodothyronine, T4 (contains 4 iodine atoms)

2. triiodothyronine, T3

(contains 3 iodine atoms)most potent & principle hormone(5x stronger)

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 restrequired for normal growth/developmentrequired for nervous sys to matureMUST have iodine*unique thyroid only gland to store hormonesinsufficient 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 Glandsfound on

posterior of thyroid gland

4 glandscomposed 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 Glandsfound atop

kidney (cap)vascularconsists of 2

glands in oneeach releases

different hormones

composed of nerve cellscells connected with sympathetic

nervous systemhormones NOT VITAL for lifesecretes 2 hormones:

1. epinephrine (adrenalin)2. norepinephrine (noradrenalin)

adrenal medulla

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”

makes up bulk of adrenal glandcomposed of epithelial cellsvascularproduces > 30 steroidsmany VITAL to life

3 main hormones:

adrenal cortex

type of mineralocorticoidhelps regulate conc of mineral

electrolytesaffects kidneys to conserve Na+ and

excrete K+ stimulates water retention

conc levels of Na+, K+, or kidney will affect hormone’s release

1. aldosterone

aka-hydrocortisonetype 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

2. cortisol

most male hormones (androgens), but changed to female hormones

stimulates early development of reproduction organs

3. adrenal sex hormones

Cushing’s disease

Pancreas2 glands in one!2 major secretory

cellsexocrine portion

secretes digestive enzymes

endocrine releases hormones

endo cells are grouped in clusters called: islets

islets contain 2 types cells:1. alpha – secrete hormone

glucagon

2. beta- secrete hormone insulin

glucagon – stimulates liver to breakdown glycogen into glucoseraises 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 Glandaka - third eyenear thalamussecretes

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