- produced in anterior pituitary gland - stimulated by CRH - post-transitional modification produces ACTH and other peptides - tissues other than adrenal gland affected by POMC fragments and peptides

- adrenal tumor secretes cortisol - pituitary tumore secretes ACTH - iatrogrenic hypercortisolism

Exam Two - endocrine two Flashcards by Catherine McDowell

_______ secretes steroid hormones

adrenal cortex

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name the layers of the adrenal cortex from outer to inner

zona glomerulosa
zona fasciculata
zona reticularis
adrenal medulla

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Zona glomerulosa produces?

aldosterone
- sodium potassium balance

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zona fasciculata produces?

glucocorticoids
(cortisol is the main one)

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zona reticularis produces?

androgens

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The adrenal medulla produces?

catecholamines
- epinephrine (80%)
- corepinephrine (20%)

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Which axis controls cortisol secretion?

HPA axis

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What are the three main components of the HPA axis?

hypothalamus
anterior pituitary gland
adrenal cortex

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in the HPA axis, the hypothalamus secretes what hormone?

CRH corticotropin releasing hormone

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in the HPA axis the anterior pituitary gland releases what hormone?

ACTH adrenocorticotropic hormone

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in the HPA axis, the adrenal cortex releases what hormone?

cortisol

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_______ is transported by corticosteroid-binding protein in the blood

cortisol

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________ also stimulates the anterior pituitary gland to release ACTH in the HPA axis

POMC or pro-opimelanocortin

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T or F: cortisol has a negative feedback loop to control the release of CRH and ACTH?

True!

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T or F? cortisol secretion control is continuous and diurnal

true

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POMC

produced in anterior pituitary gland
stimulated by CRH
post-transitional modification produces ACTH and other peptides
tissues other than adrenal gland affected by POMC fragments and peptides

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Adrenal steroid synthesis is produced in the _________

adrenal cortex

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_______ is the base of all steroid hormones

cholesterol

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cortisol systemic effects

long-term stress mediation
protective against hypoglycemia (permissive)
mostly catabolic
promotes gluconeogenesis
immune system suppression
causes negative calcium balance
influences brain/nerve function (memory/attention enhanced, mood changes, decreased pain sensitivity)

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Adrenal glucocorticoids therapeutic uses

immunosuppressant effects (inflammatory responses, treat bee stings, poison ivy, pollen allergies, prevent rejection of transplant organs)
exogenous administration may shut down ACTH production and adrenal cells (producing adrenal cells atrophy, must carefully taper)

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Hypercortisolism

adrenal tumor secretes cortisol
pituitary tumore secretes ACTH
iatrogrenic hypercortisolism

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primary hypercortisolism

adrenal gland

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secondary hypercortisolism

pituitary tumor

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tiertiary hypercortisolism

hypothalamus

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cushings disease

secondary hypercortisolism

cushings syndrome

iatrogenic hypercortisolism

hypocortisolism

addisons disease - hyposecretion of all steroid hormones

TH function

- promotes oxidative metabolism, protein synthesis, increases body heat - long-term effects on metabolism - not essential for life BUT - essential for growth and development in children and infants

thyroid follicles are...

epithelial cells

_____________ made in follicle cells

glycoprotein thyroglobulin

center filled with ____ which holds supply of hormones

colloid

thyroid hormones bind to plasma proteins such as ___________-

thyroid-binding globulin (TBG)

target cells use __________ to remove iodine from T4 to make active T3

deiodinases

C-cells produce _________-

calcitonin

TH functions

- promotes oxidative metabolism, promotes protein synthese, increases body heat - long term effects on metabolism - not essential for life - essential for growth and development in children and infants (necessary for full expression of GH in children)

TH synthesis

1 - a Na I symporter brings I into the cell. The transporter moves I into colloid 2 - follicular cell synthesized enzymes and thyroglobulin for colloid 3 - thyroid peroxidase adds iodine to tyrosine to make T3 and T4 4 - thyroglobulin is taken back into the cell in vesicles 5 - intracellular enzymes separate T3 and T4 from the protein 6 - free T3 and T4 enter the circulation

MIT

I + tyrosine monoiodotyrosine

DIT

I + MIT dilodotyrosine

MIT + DIT

DIT + DIT

T3 is more ____ but T4 is more_______

active, stable

control of thyroid secretion

hypothalamus releases TRH Ant. Pituitary releases TSH Thyroid gland releases T3&T4 negative feedback from T3 and T4 at Ant. Pituitary and hypothalamus

causes of hyperthyroidism

- pituitary tumors secreting TSH - autoimmune disease: thyroid-stimulating immunoglobulins mimic TSH (graves disease)

effects of hyperthyroidism

- goiters - increases oxygen consumption and metabolic heat production - increases muscle protein catabolism and may cause muscle weakness - hyperexcitable reflexes and psychological disturbances - influence heart b-adrenergic recepts - exophthalmos (bug eye)

treatments for hyperthyroidism

- surgical removal of gland - destroy with radioactive iodine - block biosynthesis of hormone

cause of hypothyroidism

- autoimmune disease (hashimotos) - insufficient dietary disease - others

effects of hypothyroidism

- goiters - reduced metabolic rate and oxygen consumptions (weight gain and cold senesitivities) - decreased protein synthesis - muscle weakness and aches - fatigue - myxedema (puffy) - nervous system changes in adults including: slowed reflexes speech and thought, memory problems, depression - bradycardia (slow) - cretinism (developmental disorder)

treatment of hypothyroidism

- thyroid medication (exogenous T4/3)

_______ hypothyroidism is due to lack of iodine in diet

primary

treatment for hypothyroidism

oral thyroid meds

treatment for hyperthyroidism

removal or destruction of gland or block hormone synthesis

GH effects are mostly...

anabolic

GH and IGF stimulate...

protein synthesis

GH jobs...

- increase lipolysis and gluconeogenesis - decrease glucose uptake by muscle - increase blood glucose

IGF only...

increase bone growth

GH and IGF

increase muscle growth increase soft tissue growth increase cell proliferation and differentiation

GH and IGFs inhibit ______ and promote __________

GHRH (negative feedback loop) CHIH (somatostastin)

IGFs inhibit ___ secretion directly

severe childhood deficiency of GH leads to

dwardism

childhood of over-secretion of GH leads to

gigantism

adults with excessive secretion of GH develop

acromegaly

issues with genetically engineered human growth hormone (hGH)?

- raises ethical questions - limited effectiveness - numerous side effects like insult resistance