Chapter 13: Membrane Physiology Flashcards
Are structures inside the membrane fat soluble or water soluble?
fat solube
Are structures outside the membrane fat soluble or water soluble?
water soluble
plasma; fat or water solube?
water
cytoplasm; fat or water soluble?
fat
Inside a channel, water or fat soluble?
water
What is the limiting factor for fat soluble compounds that can get through cell membrane?
concentration gradient; will stop at 50% inside, 50% outside
Which hormone’s receptor is in the cytoplasm(but still translocates to nucleus)?
cortisol
Which compounds bind to outside receptors and use second messengers?
water soluble
easy way to know fat vs water soluble drugs:
how many times it is given per day (half-life); if half-life is short it is water soluble; if half-life is long it is fat soluble
Which patients should we be careful when administering a fat soluble drug (long half-life)?
elderly, children, obese, diabetics, hypercholesteremic, pregnant pts.
Which labs should you check if pt on fat soluble drug?
liver enzymes, CPK and pancreatic enzymes
Which drug has a higher volume of distribution, fat or water soluble?
fat
Which drug has a lower volume of distribrution, fat or water soluble?
water
Water soluble drugs are excreted by which organ?
kidney
What is the one thing we can do to reduce risk of nephrotoxicity while taking water soluble drugs?
maintain adequate hydration and give bicarbs if we want to increase the excretion (water soluble are weak acids)
How do you increase the volume of distribution of a water soluble drug?
increase dose (concentration gradient rises)
If you want to treat a UTI which kind of drug should you give?
water solube, an acid, shorter half-life (i.e. penicillin, quinolone, tetracycline, etc..)
Simple explanation of Fick’s equation:
all factors that favor diffusion go at the top (numerator); all factors that negatively affect diffusion go in the denominator : If the number rises, diffusion rises; if the number gets smaller, diffusion lessens.
The two essential fats
linolenic, linoleic
What are linolenic acid and linoleic acid used for?
making arachidonic acid (for making leukotreines and prostaglandins)
What are the 3 things required for membrane movement?
Ca, ATP, microtubles
What is the oxidized protein associated with aging?
thyratron
Any sudden development of sebhorrehic keratosis could signal low energy state: what workup should we consider?
HIV, Colon cancer above 40, diabetes under 40 y/0
Any development of acanthosis nigricans, what workup should we consider?
GI cancer in older adults; diabetes in young adults or children
Do GLUT move in same direction or opposite direction as Na?
same, so they are called symporters
Do Ca move in the same direction or opposite as Na?
opposite, so the calcium transporters are called antiporters
What is a sympathetic, catabolic second messenger?
cAMP (phosphorylates all proteins); when it dephosphorylates, it becomes parasympathetic
What is a parasympathetic, anabolic second messenger?
cGMP (gamma subunite will dissociate and activate guanylate cyclase, protein phosphatase will dephosphorylate all porteins: parasympathetic becomes active, sympathetic becomes inactive
What do phophodiesterase inhibitors do?
inhibit breakdown of cAMP by phosphodiaterase (i.e. caffeine, theophylline)
Which compounds cannot be given with phosphodiesterase inhibitors?
NO, alpha blockers, hydralazine
All hypothalamic hormones (except CRH) and smooth muscle contraction use which second messenger?
IP3-DAG
What second messenger does CRH use?
cAMP
IP3 causes Ca release from sarcooplasmic reticulum but what has to bind to the Ca to activate Protein Kinase C?
DAG
What does Protein kinase C do?
phosphorylates proteins using ATP
When smooth muscle distend what do they activate?
calmodulin
What kinase do insulin and all growth factors use?
tyrosine kinase
What is sirolimus?
tyrosine kinase inhibitor
Which amino acid does NO need?
arginine
MOA of NO
activates guanylate cyclase which elevates cGMP
What does ANP use NO for ?
dilate afferent renal arterioles
Best drug for HTN in pregnancy?
Labetalol
How do nitrates help heart disease>
venodilation which decreases preload