Endocrine System Flashcards
Peptide hormones: polar or non polar?
Polar
How do peptide hormones regulate organs?
Bind to extracellular receptors –> trigger transmission of a second messenger like cAMP, inositol triphosphate, and Ca
Hormones that have a rapid onset and are short-lived: peptide or steroid hormones?
Peptide
Hormones that have a slow onset and are long lasting: peptide or steroid hormones?
Steroid
What are steroid hormones derived from?
Cholesterol
How do steroid hormones regulate organs?
Bind to intracellular or intranuclear receptors –> creates hormone-receptor complexes –> conformational change –> bind to DNA –> affect transcription of a particular gene
How do steroid hormones travel in the bloodstream?
With carriers
Are steroid hormones active in the bloodstream?
No
What can change the level of steroid hormones in the bloodstream? How?
Levels of carrier proteins –> the more carriers, the less active hormones!!
What is the thyroxine bloodstream carrier? What hormones regulate its levels in bloodstream? What does this mean for pregnant women?
TBG
Estrogen and progesterone
Must secrete more thyroxine
What are two examples of amino acid derivative hormones?
norepi and epi
Difference between direct and tropic hormones?
Direct –> direct effects on non endocrine organs
Tropic –> direct effects on endocrine organs
What is a paracrine signal?
Signal acts on cells in the local area
What is an autocrine signal?
Signal acts on the same cell that secreted the signal
What is a juxtacrine signal?
Signal acts on the adjacent cell (no diffusion)
What is an endocrine signal?
Signal acts on a distant target tissue
What are the five hormones released by the hypothalamus to the anterior pituitary? Roles?
GnRH: increase FSH and LH GHRH: increase growth hormone TRH: increase TSH Corticotropin RH: increase ACTH Prolactin inhibiting factor = dopamine: decrease prolactin
What happens if there is a tumor in the anterior pituitary that stimulates the release of PIF?
Too much prolactin will be secreted by anterior pituitary
What are the two hormones released by the hypothalamus to the posterior pituitary?
Oxytocin: stimulates uterine contractions and mammary glands contraction / smooth muscle in ductus deferens and prostate glands
Antidiuretic (ADH): increase reabsorption of water in collecting duct –> increase blood volume and decrease blood osmolarity
Does oxytocin have a positive or negative feedback loop?
+
What are the 7 hormones released by anterior pituitary? Tropic or direct? Role?
Tropic = FLAT: FSH: acts on gonads LH: acts on gonads ACTH: acts on adrenal cortex TSH: acts on thyroid
Direct: PEG
Prolactin: acts on mammary glands: stimulates milk production
Endorphins: decrease pain perception
Growth hormone: promotes bone and muscle growth and prevents glucose uptake by other tissues so that the blood glucose concentration increases + promotes fatty acid breakdown
What are the 3 hormones released by the thyroid? Role?
T3/T4: increase metabolic rate Calcitonin: decreases calcium blood concentration by: - promoting Ca excretion in kidneys - decreasing Ca absorption in gut - promoting Ca storage in bone
What can cause hypothyroidism? What are the symptoms ?
Cause: iodine deficiency or thyroid inflammation
Symptoms: lethargy, decrease in body temp, slowed respiration and heart rate, weight gain
What can cause hyperthyroidism? What are the symptoms ?
Cause: tumor or overstimulation
Symptoms: increased activity level, increase body temp, increased respiration heart rate, weight loss
What are the effects of hypothyroidism in children?
Cretinism and improper physiological development
What types of cell release T3 and T4?
Follicular cells
What types of cells release calcitonin?
parafollicular C-cells
What is the 1 hormone released by the parathyroid? Role?
PTH: increases blood calcium concentration by:
- decreasing Ca excretion in kidneys
- increasing Ca absorption in gut
- increasing bone resorption
What is the effect of PTH on vitamin D? for what purpose?
It activates it –> necessary for Ca and phosphate absorption in gut
Does PTH affect the blood phosphate concentration?
No
What are the 3 classes of hormones released by the adrenal cortex?
- Glucocorticoids
- Mineral corticoids
- Cortisol sex hormones
What are the 2 glucocorticoids? Role?
Cortisol and cortisone:
- increase blood glucose
- decrease protein synthesis
- inhibit immune system
- -> stress response
What is the mineral corticoid released by the adrenal cortex? Role?
Aldosterone:
- increase water resorption by kidneys by increasing sodium resorption: increase blood volume, but no change in osmolarity
What is aldosterone secretion regulated by?
Renin-angiotensin-aldosterone system:
- decrease blood pressure
- baroreceptors secrete renin
- angiotensinogen is activated to angiotensin I
- ACE converts it to angiotensin II
- Stimulates adrenal cortex
- Secretion of aldosterone
- Negative feedback loop
What are the cortisol sex hormones? Role?
androgens and estrogen: can masculinize females genitalia
What are the two hormones secreted by adrenal medulla? Role?
Epi and norepi: sympathetic NS response
What are the 2 stress response? Which is fast/slow?
- Cortisol/cortisone: slow
2. epi/norepi: fast
What are the 4 hormones that raise blood glucose levels?
- Glucagon
- Growth hormone
- Glucocorticoids
- Epi/norepi
What are the other 4 organs that release hormones? Role?
- Stomach/intestine: secretin, gastrin (HCl secretion), cholecystokinin, ghrelin
- Kidneys: eryothropoietin: stimulates bone marrow to produce erythrocytes
- heart atria: ANP: promotes excretion of salt and water in response to high blood volume
- Thymus: thymosin: stimulates T-cell development
What hormones promote hunger?
Glucagon, ghrelin, and orexin
What hormones promote satiety?
Leptin and cholecystokinin (CCK)
What cells produce insulin?
Beta cells
What cells produce glucagon?
alpha cells
What cells produce somatostatin?
delta cells
How do hormones bind to receptors?
Hormonal controls are covalent through phosphorylation and dephosphorylation → they modify covalent bonds
List the 5 steroid hormones
glucorticoids, mineral corticoids, testosterone, estrogen, progesterone.
List the 4 amino-acid derivative hormones. What aa do they come from?
T3, T4, epi, norepi (all from tyrosine)
Are steroid hormones stored within the cell? Why?
No, because they are nonpolar and would freely exit the cell and diffuse out
What hormones promote thirst?
ADH and aldosterone
