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Old 03-21-2019, 11:06 AM
Cecily Cecily is offline
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Join Date: Jan 2012
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That’s about everything. Hour left to study.

SA node to AV node to bundle of his to L/R bundle branches to purkinje fibers

PR interval is begining of P to Q boxes x .04
Normal value = .16 to 18 seconds

Longer suggests heart block

QRS complex = Q to R boxes x .04
Normal value = .08 to .10 seconds

Longer suggest r/l bundle branch block

QT interval = Q to end of T x .04
Normal Value = .3 to .4 seconds

Shorter with increased HR

H20+C02 <-> H2OCO3 <-> HCO3- + H+

Water combines with carbon dioxide to form carbonic acid, this reaction catalyzed by enzyme carbonic anhydrase carried in RBCs. CO2 diffuses into RBC -> gets turned to carbonic acid -> acid disassociates into bicarbonate ion and Hydrogen.

More hydrogen ions more acidic. More CO2 (hypoventilation) more hydrogen, more acidic, pH down. Vice versa.

Normal blood pH 7.4, 7.35 to 7.45
<7.35 acidosis >7.45 alkalosis

Diaphragm contracts, moves down. External intercostal contract, sternum / chest moves up and out. Volume in lungs increases, lowers pressure below atmospheric pressure and air moves down pressure gradient = inspiration.

Exspiration = diaphragm / intercostals relax. Chest moves down and pressure increases as volume decreases. Air in lungs higher pressure than atmosphere and moves down pressure gradient.
Last edited by Cecily; 03-21-2019 at 11:12 AM..