Card Set Information
Classically, hormones are carried by _______ to _______, but they have __________.
blood; all cells of the body; specific target cells
Blood hormone concentrations are typically very _______.
__________ defines a hormone's target tissue.
Receptor-hormone binding is very ________ and ________.
Hydrophobic hormones usually have a ______ molecular weight; their synthesis is by ____________; they bind _________ receptors.
small; multi-step enzyme-mediated processes; intracellular
What type of hormones are made only when you need them, and what type are stored in vesicles?
made when needed- hydrophobic; stored- hydrophillic
Which type of hormones can cross membranes?
hydrophobic (lipid soluble)
Hydrophilic hormones usually have a _________ molecular weight; their synthesis is by __________; they bind ___________ receptors.
large; mRNA-directed processes; plasma membrane
Receptors for hydrophobic hormones are ___________ located on target cells and generate an __________ chemical signal, stimulating a _________ in the target cell.
proteins; intracellular; functional change
Receptors for hydrophilic hormones are __________ and stimulate ____________, causing...
membrane-bound; activation of second messengers; metabolic pathways and/or transcription factors
Receptor tyrosine kinases (RTKs) are receptors of __(3)__.
hormones, growth factors, cytokines
GPCR is a member of the ___________ receptor family.
7 trans-membrane (7TM)
GPCR are receptors of __(3)__.
pheromones, neurotransmitters, hormones
Receptors of hydrophobic hormones are found in the __(2)__ and function as ___________.
cytoplasm and nucleus; transcription factors
GPCR and RTKs are _________ receptors; hydrophilic hormones that associate with these receptors include... (3)
membrane-associated; amines, peptides, and protein hormones
Cytosolic/nuclear hormones include ____________, and two examples are...
fat soluble hormones; steroids and thyroid hormones
The minimal hormone concentration able to elicit a cellular response.
The breadth of receptor types able to bind a specific hormone.
How can hormones generate a biological response when they are presented in extremely low levels?
through signal amplification (hormone activates MANY secondary messengers)
Describe the gastrin feedback loop.
gastrin causes increased acid secretion in the stomach; increased acid decreases gastrin release
Describe the aldosterone feedback loop.
aldosterone causes a decrease in potassium; decreased potassium stops the synthesis of aldosterone
Describe the calcitonin feedback loop.
calcitonin causes an increase in calcium; increased calcium ceases the release of calcitonin
TRH in the hypothalamus increases ________ in the _________.
TSH; anterior pituitary
TSH in the anterior pituitary increases ___(2)___ in the _________, which consequently decreases __(2)__.
T3 and T4; thyroid gland; TSH and TRH