REVIEW RAMBLINGS Flashcards
(129 cards)
What is the predominant tone of the eyes?
Iris radial muscle = sympathetic (a1)
Iris circular muscle = parasympathetic (m3)
Ciliary muscle = parasympathetic (m3)
(But ß also relaxes it)
What is the predominant tone of the heart?
Main tone comes from SA node = parasympathetic (m2) slows it down
(But ß1/ß2 accelerate it)
Predominant tone of the blood vessels
Predominant are the skin, splanchnic vessels = sympathetic (alpha contracts them)
Skeletal muscle vessels relax by ß2
Endothelium by NO release
Predominant tone of the bronchiolar smooth muscle
Parasympathetic (m3) —> contracts
Also relaxes by ß2 but no innervation
What is the predominant tone of the GI tract?
Parasympathetic (M3)
What is the predominant tone of the GU smooth muscle?
Parasympathetic (M3)
What is the predominant tone of the skin?
Sympathetic
Pilomotor smooth muscles and apocrine sweat glands are alpha, but eccrine is M (even though its sympathetic)
Describe presynaptic receptor regulation
IT’S A BIG KRIS-KROSS (see pic on slide 9)
Sympathetic fibers release NE, which can bind to its own a2 receptor and inhibit further release of NE
Parasympathetic fibers can also act upon sympathetic fibers by releasing ACh on M2 receptors —> inhibit NE release
Parasympathetic fibers release ACh which can act upon its own M2 receptors to inhibit further release of ACh
Sympathetic fibers can also act upon parasympathetic fibers by releasing NE on a2 receptors —> inhibit ACh release
How is postsynaptic regulation achieved?
Up-regulation of receptors (or denervation)
Down-regulation or desensitization of receptors (from excessive stimulation)
Other modulators regulating membrane potentials such as IPSP M2 or EPSP peptides
What are the steps of the baroreflex?
- Baroreceptor in carotid sinus senses arterial BP
- Signal to inhibitory interneurons in nucleus of the tractus solitarius
- Inhibitory interneuron signals vasomotor center
- Signal goes to autonomic ganglion —> motor fibers to sympathetic nerve ending —> a or ß receptor
See the animation on slide 13
General rules rules regarding drug effects
Any decrease in BP —> reflex tachycardia (immediate)
Any decrease in BP —> increased renin release —> increased Na+ and H2O retention (long term effect)
Name all the Carbonic Anhydrase Inhibitors
ACETAZOLAMIDE (Diamox)
Dorzolamide (Trusopt)
Brinzolamide (Azopt)
The last two are eye drops
What is the MOA for CA Inhibitors?
Inhibits CA enzyme —> blocks H2CO3 production —> Reduces H+ for exchange with Na+, resulting in INCREASED SODIUM (and H2O) LOSS
DOC for acute mountain sickness
Acetazolamide (Diamox)
How long does Acetazolamide last?
Diuretic effectiveness decreases in several days (why it’s not used as a regular diuretic)
What’s the main adverse effect of CA inhibitors?
HYPERCHLOREMIC metabolic acidosis
Develops b/c the Na+ loss is in the form of NaHCO3 and not NaCl
What is the prototype Loop Diuretic
Furosemide (Lasix)
MOA for Loop diuretic
Blocks the 1 Na+ 1 K+ 2 Cl- cotransporter
—> increased Na+ in the lumen —> diuresis
Most important indication for Furosemide
PULMONARY EDEMA - relieves pulmonary congestion by increasing systemic venous capacitance
HF - moves large volumes of water
Hypercalcemia - loops reduce reabsorption of Mg2+ and Ca2+ by reducing the K+ gradient
Most important adverse effect of Loops
HYPOKALEMIC METABOLIC ALKALOSIS - induces K+ and H+ loss at the DCT
Others: Hypocalcemia Hypomagnesemia Hyperuricemia Irreversible ototoxicity
Why makes Ethacrynic Acid a special Loop?
It’s not a sulfonamide derivative
It has the highest risk of ototoxicity
MOA for Thiazide Diuretics
Inhibition of sodium resorption at the early distal tubule by INHIBITION of the Na+ Cl- co-transporter
Dependent on PG synthesis
Major beneficial effect of thiazides
Relaxation of smooth muscle cells —> VASODILATION
Major adverse effects of thiazides
Reduced insulin secretion—> HYPERGLYCEMIA***
HYPOKALEMIC metabolic alkalosis***
Hyperuricemia