Lecture 1 - Hormones Flashcards
Define hormone
A substance in the body that transmits a signal to produce an effect or alteration at the cellular level
What are the major glands of the endocrine system?
Hypothalamus, pituitary, thyroid, parathyroids, adrenals, pineal body
What are the major organs of the endocrine system?
ovaries, testes, pancreas, kidneys
Define endocrine
hormone released into bloodstream to contact distant cell
Define paracrine
hormone released to contact a neighboring cell
Define autocrine
hormone released onto itself
What are peptide and protein hormones?
Products of translation
Are peptide and protein hormones hydrophobic or hydrophilic?
Hydrophilic
Are peptide and protein hormones carrier proteins?
No
How are peptide and protein hormones released?
The cell stores them in secretory granules and releases them in “bursts” when stimulated = allows cells to secrete a large amount of hormone over a short period of time
OR
Cell synthesizes them and releases them immediately in secretory vesicles
What are neurophysins?
Carrier proteins for vasopressin and oxytocin
Neurophysin I - oxytocin
Neurophysin II - vasopressin
What type of hormone is vasopressin?
Anti-diuretic hormone
What is oxytocin known as and when is it released?
“Love hormone”, released during childbirth and breastfeeding
Who does Type 1 diabetes affect and what causes it?
Juveniles, pancreatic cells destroyed = no insulin production
Who does Type 2 diabetes affect and what causes it?
Adults, body does not produce enough insulin and/or does not utilize insulin efficiently = insulin resistance
What is the main reason why Type 2 diabetes is more prevalent than Type 1?
Obesity
How is Type 1 diabetes treated?
Insulin injections
How is Type 2 diabetes treated?
Diet and exercise; Drugs targeting organs involved in glucose metabolism; chronic cases- insulin injections
Are amino acid-derived hormones hydrophobic or hydrophilic?
Both
How are amino acid-derived hormones released?
Depends on hormone
Are amino acid-derived hormones carrier proteins?
Yes
What type of hormones are norepinephrine and epinephrine?
Amino acid-derived hormones
Which amino acid is norepinephrine (no adrenaline) synthesized from? Where is it synthesized?
Phenylalanine, adrenal medulla
Which amino acid is epinephrine (adrenaline) synthesized from? Where is it synthesized?
Tyrosine, adrenal medulla
Cortisol initiates the synthesis of ______?
PNMT (Phenylethanolamine N-methyltransferase)
Which enzyme converts norepinephrine to epinephrine?
PNMT (Phenylethanolamine N-methyltransferase)
Define catecholamines
hydrophilic hormones/neurotransmitters that respond to stress, which in turn, accelerates heartbeats, increases blood pressure, and increases blood flow
Are catecholamines hydrophobic or hydrophilic?
Hydrophobic
Is the thyroid hormone hydrophobic or hydrophilic?
Hydrophobic
Where does thyroid hormone synthesis occur?
Follicular space of thyroid gland
What are the steps of thyroid hormone synthesis?
1) Thyroglobulin contains about 100-120 Tyrosine residues
2) Uptake of Iodide (I-)
3) Oxidation to Iodine (I)
4) Iodination of thyroglobulin (on tyrosine residues)
5) Formation of MIT (monoiodotyrosine) (T1) and DIT (diiodotyrosine) (T2)
6) Polymeric molecules T3 (triiodothyronine) and T4 (thyroxine; tetraiodothyronine)
7) Secretion
T3 is the _____ _____ hormone.
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