Flashcards in Hormones and Receptors Deck (43):
Is the endocrine system ductless or does it contain ducts?
Are glands anatomically distinct?
Yes, but do form functional system
What does the anterior pituitary release to cause the adrenal cortex to make cortisol?
By what three ways is specificity of signalling achieved?
- chemically distinct hormones
-specific receptors for each
-distinct distribution of receptors across target cells
Name the 3 main classes of hormones.
Glycoproteins and peptides
Tyrosine and tryptophan derivatives
Which hormone class is most diverse?
glycoproteins and peptides
Give an example of the glycoproteins and peptides class
oxytocin or insulin
Give examples of steroids.
Give examples of Tyrosine and tryptophan derivatives.
adrenaline, melatonin and thyroid hormones
Are amines, peptides and proteins hydrophilic or phobic, and are they transported freely or bound?
Are steroids hydrophilic or phobic, and are they transported freely or bound?
hydrophobic, bound to plasma proteins
Are steroids and thyroxine soluble or insoluble in plasma?
What is the function of carrier proteins?
-increase amount of hormone transported in blood
-prevent rapid excretion by preventing filtration at kidney
What act as a buffer and ensure free and bound hormones are in equilibrium?
Is albumin a specific or general carrier protein?
What does albumin bind?
What does transthyretin bind?
Do peptides and proteins need carrier proteins and why?
no, are soluble in plasma
What type of hormones, free or bound, can cross the capillary wall?
What does cortisol bind globulin bind to sometimes as well as cortisol?
What does thyroxine binding globulin bind to?
T4 (thyroxine) as well as some triiodothyronine (T3)
What does sex steroid binding globulin (SSBG) bind to mostly?
testosterone and estradiol
What buffer surges in hormone?
What is the primary determinant of plasma secretion?
rate of secretion
What 3 things is rate of secretion subject to?
- negative feedback control
- neuroendocrine (sudden bursts of secretion in response to stimulus eg stress)
Does rate of elimination contribute to plasma concentration?
How does rate of elimination generally occur?
By liver metabolism and kidney excretion
How long does amine elimination take?
How long does protein/peptide elimination take?
How long does steroid elimination take?
hours - days
What are the 3 main types of hormone RECEPTOR?
- G protein coupled
- receptor kinases
What is the receptor for insulin an example of?
Which classes are cell surface receptors?
G protein coupled and receptor kinases (nuclear receptors are intracellular)
What are G protein coupled receptors activated by?
amines and some proteins/peptides
What are receptor kinase receptors activated by?
How many classes are there of nuclear receptors?
3 (1, 2 and hybrid)
What activates class 1 nuclear receptors?
Where are class 1 nuclear receptors when activated and when not?
no activated - cytoplasm, bound to heat shock proteins
Where are class 2 nuclear receptors?
What activates class 2?
What activates the hybrid class?
What class is the hybrid class similar to in function?