endocrine system

extracellular receptors

peptide hormones

intracellular receptors

steroid hormones

insulin hormone classification

peptide hormone

peptide hormone

water soluble no carrier, charged with extracellular receptors, rapid and short acting through signaling cascades and secondary messengers

steroid hormone

lipid soluble requires carrier, intracellular receptors, slow and long acting through conformational changes and direct dna binding

catecholamines

norepinephrine and epinephrine amino acid peptide hormones bind g protein coupled receptors

norepinephrine hormone classification

catecholamine amino acid peptide hormone

epinephrine hormone classification

catecholamine amino acid peptide hormone

triiodothyronine hormone classification

amino acid hormone

thyroxine hormone classification

amino acid hormone

direct hormones

act directly on target tissue

hormones that act directly on target tissue

direct hormones

tropic hormones

acts on an endocrine gland to secrete intermediary hormone

exert effect through intermediary hormone

tropic hormones

gnrh

hypothalamic hormone acts on anterior pituitary to release fsh and lh

ghrh

growth hormone-releasing hormone from hypothalamus acts on anterior pituitary to release growth hormone

trh

thyroid releasing hormone from hypothalamus acts on anterior pituitary to release tsh

crf

corticotropin releasing factor from hypothalamus acts on anterior pituitary to release acth

pif

prolactin inhibiting factor (dopamine) from hypothalamus acts on anterior pituitary to decrease prolactin secretion

growth hormone axis

ghrh, gh, igf-1

gonad hormone axis

gnrh, lh, estrogen/testosterone

thyroid hormone axis

trh, tsh, t3/t4

stress hormone axis

crf, acth, cortisol

hormones of the anterior pituitary

fsh, lh, acth, tsh, prolactin, endorphins, gh

lactation

inhibited by hypothalamic dopamine (pif). anterior pituitary secretes prolactin for milk production, posterior pituitary secretes oxytocin for smooth muscle contraction

epiphyseal plates

origins of bone growth

gigantism

excess of GH released before sealing of plates

dwarfism

deficit of GH before sealing of plates

acromegaly

excess of GH released after sealing of plates

posterior pituitary hormones

adh and oxytocin

conditions for adh secretion

low blood volume or increased blood osmolarity

t3

triiodothyronine sets basal metabolic rate

t4

thyroxine promotes calcium homeostasis, regulates calcitonin

hyperthyroidism

increased t3, t4, decreased tsh, increased cellular respiration, synthesis and degradation of proteins and fatty acids, increased body temperature, heat intolerance, weight loss

hypothyroidism

decreased t3, t4, increased tsh, decreased cellular respiration, decreased body temperature, cold intolerance, weight gain

cell types of thyroid

follicular and c-cells

follicular cells

produce t3, t4 thyroid hormones

c-cells

produce calcitonin

calcitonin

secreted by thyroid lowers blood calcium by increasing calcium excretion, decreasing calcium absorption, increasing bone growth by osteoblasts

parathyroid hormone

secreted by parathyroid raises blood calcium by decreasing calcium excretion, increasing calcium absorption and vitamin D, increasing bone resorption by osteoclasts

types of corticosteroids

glucocorticoids, mineralocorticoids, cortical sex hormones

glucocorticoids

steroid corticosteroids released by adrenal cortex that regulates glucose levels. cortisol and cortisone decrease inflammation

cortisol

glucocorticoid secreted by adrenal cortex regulates glucose levels released in times of stress

mineralocorticoids

corticosteroid secreted by adrenal cortex used in salt and water homeostasis

aldosterone

mineralocorticoid secreted by adrenal cortex increases sodium reabsorption, decreases potassium and hydrogen ion reabsorption, increases blood volume and pressure

renin

secreted by kidneys cleaves angiotensinogen into angiotensin i

ace

angiotensin-converting enzyme converts angiotensin i to angiotensin ii in lungs

angiotensin ii

stimulates adrenal cortex to secrete aldosterone to increase blood pressure

cortical sex hormone

corticosteroid secreted by adrenal cortex. androgens and estrogens in addition to gonad secretion

secretes epinephrine and norepinephrine

adrenal medulla

epinephrine

catecholamine secreted by adrenal medulla increases glycogenolysis to glucose in liver and muscle, increases basal metabolic rate. short term stress response

islets of langerhans

small clusters of hormone producing cells of the pancreas

secrete glucagon

alpha cells of islets of langerhans

secrete insulin

beta cells of islets of langerhans

secretes somatostatin

delta cells of islets of langerhans

hypoglycemia

low blood glucose by excess insulin

diabetes mellitus

hyperglycemia overwhelms nephron’s reabsorption of glucose

polyuria

increase in urine volume due to increased osmolarity by excess glucose in urine

increased thirst resulting from polyuria

polydipsia

type i

insulin dependent; autoimmune disease of the beta islet cells

type ii

non insulin dependent; insulin resistant receptors

somatostatin

secreted by hypothalamus inhibits growth hormone, both insulin and glucagon secretion due to high blood glucose and amino acid concentration

pineal gland

located in brain, secretes melatonin in response to retina projections to control circadian rhythm

erythropoietin

produced by kidneys to stimulate production of erythrocytes from bone marrow when blood oxygen is low

anp

atrial natriuretic peptide released by heart to promote excretion of sodium and increase urine when atrial cells stretch

thymosin

released by thymus for T cell development and differentiation in childhood