Endocrine System Flashcards
Give examples of exocrine glands.
eccrine & apocrine glands, sebaceous glands, lacrimal glands, digestive glands
List the main endocrine glands of the body.
hypophysis, pineal, thyroid, parathyroid, adrenal
How is IL-2 both a paracrine and autocrine hormone?
IL-2 is released by helper T cells and causes greater proliferation of helper T cells, and activation of T and B cells
NO is released by… and causes…
endothelial cells
vasodilation/relaxation of blood vessel smooth mm (global decrease in BP)
What are 3 examples of water-soluble hormones?
amine hormones, peptide/protein hormones, and eicosanoid hormones
can also say:
ADH, oxytocin, hGH, insulin, TSH (glycoprotein)
What are 3 examples of lipid-soluble hormones?
steroid hormones, thyroid hormones and nitric oxide
can also say:
corticosteroids, glucocorticoids, mineralocorticoids, androgens, estrogens, progesterone, T3, T4,
Steroid hormones are derived from…
cholesterol
Which amine hormones are catecholamines? What are they derived from?
E, NE, and dopamine
tyrosine
Histamine is an __ hormone derived from ___
amine, histidine
What are two examples of eicosanoid hormones?
PGs and LTs
3 factors affect responsiveness of target cells to a hormone:
- blood concentration levels
- # of receptors on target cell
- influence of other hormones
Describe a “permissive effect”
simultaneous or recent exposure to a 2nd hormone is required for the first hormone to act
Describe a “synergistic effect”
two hormones acting together is greater/more powerful than the effect of each acting alone
Describe an “antagonistic effect” and give an example.
one hormone opposes the action of another
insulin and glucagon have opposite actions: promoting synthesis vs. breakdown of glycogen
The adenohypophysis is composed of 75%…
epithelial tissue
The two portions of the adenohypophysis are…
the pars distalis and pars tuberalis
The main function of hGH is…
promoting and secreting IGFs (somatomedins)
Translate:
somatomedin
somatostatin
somatocrinin
somatomedins: IGFs
somatostatin: GHIH
somatocrinin: GHRH
IGFs decrease the breakdown of __ and the use of ___ in gluconeogenesis
proteins, amino acids
IGFs stimulates the liver to…
release glucose into bloodstream
Secretion of hGH is promoted by…
decreased fatty acids and increased amino acids in the blood
hGH secretion is inhibited by…
high levels of fatty acids, decreased amino acids
obesity, hypothyroidism
PRL requires permissive effects on mammary gland cells from…
estrogens, progesterone, glucocorticoids, hGH, thyroxine, insulin
Thyroxine is…
T4
The neurohypophysis is composed of two parts, which contain:
pars nervosa and pars intermedia
containing axons and terminals of hypothalamic secretory cells
What hormones does the posterior pituitary produce?
none. it only secretes OT and ADH (vasopressin)
What are the effects of ADH?
decreased sweating
increased BP
water retention
What occurs in diabetes insipidus?
hyposecretion of ADH or non-functional ADH receptors leading to intense thirst and excretion of large amounts of urine
What is monitored regarding the release of ADH?
blood osmotic pressure, dehydration, loss of blood volume, pain/stress
Two lobes of the thyroid gland are united by the…
isthmus
The parafollicular cells of the thyroid gland produce…
calcitonin (CT)
Which gland is the only endocrine gland to store its secretions in large quantities? (100-day supply)
thyroid gland!
Which thyroid hormone is secreted in larger quantities? Which is more potent?
T4 is secreted in larger quantities
T3 is several times more potent
Which thyroid hormone is converted to the other inside the cell?
T4 –> T3
What molecule transports T3 & T4 in the blood?
TBG (thyroxine-binding globulin)
Differentiate TGB and TBG
TGB is thyroglobulin, required for synthesis of thyroid hormones
TBG is thyroxine-binding globulin, used for transporting T3/T4 in the blood
What are some actions of thyroid hormones?
increase BMR/metabolism
stimulates synthesis of additional Na/K pumps
increases body temperature
stimulates protein synthesis
reduces blood cholesterol
accelerates body growth with hGH and insulin
enhances actions of catecholamines (HR, heart contraction force, BP)
Thyroid hormone secretion increases in conditions that increase ATP demand, such as…
cold environment, high altitude, pregnancy
What is special about Miacalcin?
it’s 10x more potent than CT and prescribed for osteoporosis
True or false: high iodine levels suppresses T3/T4 secretion
true
Which hormone promotes uptake of calcium and phosphates into bone extracellular matrix?
calcitonin
Where are the parathyroid glands in relation to the thyroid gland?
posterior surface of the lateral lobes
PTH is the major regulator of blood levels of what minerals?
calcium, magnesium, phosphates
What hormone promotes formation of calcitriol?
PTH
How is the pituitary gland involved in blood calcium regulation by CT & PTH?
It is not involved!
Define ‘polyuria’
large amounts of urine excretion
Define ‘polydipsia’
intense thirst even after drinking fluids
What is the most abundant glucocorticoid in the body? What is its synthetic name?
What are the others?
cortisol (hydrocortisone) (95%)
prednisone is the prescription version
corticosterone, cortisone
What are the 3 zones of the adrenal cortex?
zona glomerulosa
zona fasciculata
zona reticularis
How does aldosterone help regulate body pH?
promotes excretion of H+ in the urine
What are the triggers for the renin-angiotensin-aldosterone pathway?
decreased BP or blood volume
dehydration, Na+ deficiency, hemorrhage
What triggers the release of renin? What does renin convert?
LBP
angiotensinogen –> angiotensin I
How does aldosterone increase blood pressure?
increase reabsorption of Na+ from kidneys & excretion of H+ & K+
angiotensin II stimulates arteriole constriction
What are the 6 effects of glucocorticoids?
- protein catabolism
- glucose anabolism (gluconeogenesis)
- lipolysis
- stress resistance
- anti-inflammation (WBC inhibition –> delay repair/healing)
- depression of immune response
How does PTH affect blood Ca2+ levels?
stimulates osteoclasts
stimulates kidneys to release calcitriol
slows loss of Ca2+ in urine
Who releases calcitonin? What does it do to affect blood-Ca2+ levels?
parafollicular cells of the thyroid gland
inhibits osteoclasts
Tropins/tropic hormones are released from…
the pituitary gland (not hypothalamic neurons!)
What is the major hormone secreted by the zona reticularis?
DHEA: dehydroepianrosterone
Zona glomerulosa is the ___most portion of the adrenal cortex, which secretes…
mineralocorticoids
Zona fasciculata is the ___ of the adrenal cortex and secretes…
middle, glucocorticoids
