Endocrine System Flashcards by sam tunks

What cell type produces calcitonin?

parafollicular

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Thyroid hormone

T3 is more powerful than T4 but if T3 production is compromised, an iodine can be removed from T4 to create T3. This can lead to thyroid problems later down the line

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Thyroid hormone functions

increases metabolism, heat production, development of skeletal and nervous systems, reproduction and BP maintenance

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Thyroxine-binding globulins

transports T3 and T4

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T/F the release of thyroid hormone is a negative feedback loop

true

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Hypothalamic thyrotropin-releasing hormone

takes over negative feedback loop during pregnancy

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Hypersecretion of thyroid hormone

Grave’s disease

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Hyposecretion of thyroid hormone

-Myxedema and goiter if lack of iodine in adults
-cretinism in children

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Calcitonin

-antagonist to parathyroid hormone
-Inhibits Ca2+ release from bone matrix
-stimulates Ca2+ uptake

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Oxyphil and chief cells

-found in parathyroid
-secrete parathormone

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Parathormone (PTH)

-most important hormone in Ca2+ uptake
-osteoclast stimulation to release Ca2+ for reabsorption, phosphate secretion from kidneys, vitamin D activation from kidneys
-negative feedback

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Hyperparathyroidism

-due to tumor
-bones soften and deform
-elevated Ca2+ depresses nervous system and causes kidney stones

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Hypoparathyroidism

-gland trauma/removal or magnesium deficiency
-tetany, respiratory paralysis, death
-contractions in facial muscles
-inflating of a bp cuff causes carpal spasm

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Corticosteroid production

Zona glomerulosa- Mineralocorticoids: aldosterone for salt reabsorption
Zona fasciculata- glucocorticoids (sugar)
Zona reticularis- gonadocorticoids (sex)

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Aldosterone

-stimulates Na+ reabsorption and H2O retention by kidneys
-release triggered by decreasing bp and blood volume and rising levels of blood K+

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ANP

secreted by heart (right atrium) and works via urination, blocks renin and aldosterone secretion to decrease bp

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Aldosteronism

-hypersecretion due to adrenal tumors
-symptoms include hypertension and edema due to excess sodium

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Thymus produces ____

t-lymphocytes

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Exocrine glands

-non hormonal
-have ducts to carry secretion to surface

Endocrine glands

-hormonal
-no ducts
amino acids proteins peptides

Steroids

synthesized from cholesterol
gonadal and adrenocortical hormones

Water soluble hormones

-act on plasma membrane receptors
-act via g protein second messengers
-cannot enter the cell
-all amino acid based hormones except thyroid hormone

Lipid soluble hormones

-steroid and thyroid hormone
-act on intracellular receptors
-directly activate genes
-can enter cell

cAMP signaling mechanism

hormone binds to receptor
receptor activates g protein
g protein activates adenylate cyclase
adenylate cyclase converts ATP to cAMP
cAMP activates protein kinases for protein phosphorylation

cAMP is degraded by...

phosphodiesterase

Steroid hormones and thyroid hormone signaling mechanism

1. diffuse into target cells and bind to intracellular receptors 2. Receptor-hormone complex enters nucleus and binds to a specific region of DNA 3. Prompts dna transcription to produce mRNA 4. mRNA directs protein synthesis 5. promote metabolic activities

Up-regulation

target cells form more receptors in response to low hormone levels

Down-regulation

target cells lose receptors in response to high hormone levels

Hormone release is controlled by a _____ feedback system

negative

Endocrine gland stimulated to synthesize and release hormones in response to

1. humoral stimuli 2. neural stimuli 3. hormonal stimuli

Humoral stimuli

changing in blood levels of ions and nutrients

Neural stimuli

nerve fibers stimulate hormone release

Hormonal stimuli

hormones stimulate other endocrine organs to release their hormones

T/F endocrine system cannot override normal endocrine controls

false

Steroids and thyroid hormone are attached to ___ in the blood

plasma proteins

Pituitary gland lobes

1. posterior pituitary: neural tissue 2. Anterior pituitary: glandular tissue

Posterior pituitary

-nuclei of hypothalamus produce oxytocin and antidiuretic hormone

Anterior lobe

-originates as out pocketing of oral mucosa -vascular connection to hypothalamus

Oxytocin

-stimulant of uterine contraction -hormonal trigger for milk ejection

Anti diuretic hormone (ADH)

-prevents urine formation -regulates water balance -targets kidney tubules to reabsorb more water -deficiency is diabetes insipidus -retention of fluid, headache, and disorientation are symptoms of inappropriate secretion -to treat, monitor blood sodium level and reduce fluids

Anterior pituitary hormones

growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormones, and prolactin

Growth hormone

-increases blood levels of fatty acids, encourages use of fatty acids for fuel -decreases rate of glucose uptake and metabolism, conserving glucose -major targets are bone and skeletal muscle

Growth hormone release regulated by...

-hypothalamic hormones -growth hormone releasing hormone -growth hormone inhibiting hormone

Thyroid stimulating hormone

-stimulates neural development aactivitynd secretory activity of thyroid -release triggered by thyrotropin-releasing hormone from hypothalamus -inhibited by rising blood levels of thyroid hormones

Adrenocorticotropic hormone

stimulated adrenal cortex to release corticosteroids

Gonadotropins

-follicle stimulating hormone and luteinizing hormone

Prolactin

-stimulates milk production -regulated by dopamine and estrogen