Question | Answer |
blood flow | (deoxy) Right atrium, tricuspid valve, right ventricle, pulmonic valve, pulmonary artery, lungs, (oxy) pulmonary vein, left atrium, mitral valve, left ventricle, aortic valve, aorta, the rest of the body |
cardiac impulse | SA node → AV node → bundle of His →RBB/LBB RBB → RV → Purkinje fibers→ ventricular contraction LBB → LV → Purkinje fibers → ventricular contraction |
SA node | Location Junction of superior vena cava and RA “Primary Pacemaker of the Heart” Inherent firing rate 60-100 bpm Atrial Contraction Impulses cause atria to contract (must be conducted through myocardium for ventricular contraction) |
AV node | Location Group of nodal cells RA wall above tricuspid valve Inherent rate 40-60 bpm Impulse conduction atria to ventricles Mediates conduction btw atria and ventricles |
resting potential | Movement of ions in and out of cell changes charge, thus changing it (usually negative); electrical potential of a neuron when not stimulated |
action potential | causes response in cell and this electrical impulse/charge may be passed on |
depolarization | When resting potential made less negative, cell does this and moves toward action potential |
repolarization | reverts back to resting state |
refractory period- absolute | Completely unresponsive (phases 1- rapid repol and 2- plateau); NO early depolarization |
refractory period- relative | Short time at end of phase 3 (final repol) ; Premature depolarization if very strong electrical stimulus; Premature contractions result (PAC, PVC); Increase risk of serious dysrhythmia |
refractory period- causes | Electrolyte disturbances (hypokalemia or hyperkalemia, hypomagnesemia); Hypoxemia; Acidosis; Hypothermia; Increase in catecholamines; Myocardial injury; Chamber enlargement |
calcium | mainly at nodes b/c slower movement; opening the channels for the plateau of the action potential |
potassium | for repolarization (short hyperpolarization period) and return to resting membrane potential |
sodium | rapid, spike-like onset of the ventricular action potential |
EKG | Traces of electrical currents detected by leads on skin; Detects electrical activity, primarily LV |
P wave | atrial depolarization |
QRS | ventricular depolarization |
T wave | ventricular repolarization |
U wave | repolarization of purkinje fibers |
PR interval | time needed for SA node stimulation, atrial depolarization, and conduction thru AV node, before ventricular depolarization |
TP interval | no electrical activity, time btw repolarization of ventricles and reoccurrence of activity at SA node |
QT interval | total time for ventricular depolarization and repolarization….. Specific calculations to correct QT interval for comparison secondary varies based on age, gender, and HR…… increased risk of lethal dysrhythmia if prolonged QT |
ST segment | represents early ventricular repolarization… analyze if above or below isometric line b/c sign of ischemia/infarction if not at baseline |
V/Q ratio | ventiliation/ perfusion Normal- »Normal ratio of ventilation to perfusion |
Low V/Q | (“Shunt”) MISMATCH ventilation < perfusion (bloodflow but no alveolar air) Ex: pneumonia, mucus plug |
High V/Q | (“Dead Space”) MISMATCH ventilation > perfusion (alveolar air but no bloodflow) Ex: pulmonary emboli, pulmonary infarct |
Absence V/Q | (“Silent Unit”) MISMATCH NO ventilation or perfusion (or severely limited) Ex: Pneumothorax |
Olfactory | 1 smell |
Optic | 2 visual acuity/fields |
Oculomotor | 3 move the eye and lid, pupillary constriction, lens accommodation |
Trochlear | 4 move the eye |
Trigeminal | 5 facial sensation |
Abducens | 6 move eye laterally |
Facial | 7 expression and muscle movement, salivation and tearing, taste, sensation in the ear |
Acoustic (Vestibulocochlear) | 8 equillibrium, hearing |
Glossopharyngeal | 9 Taste, sensation in pharynx and tongue, pharyngeal muscles, swallowing |
Vagus | 10 Muscles of pharynx, larynx, soft palate, Sensation in external ear, pharynx, larynx, thoracic and abdominal viscera, parasympathetic innervation of abdominal and thoracic organs |
Spinal accessory | 11 Trapezius and sternocleidomastoid strength |
Hypoglossal | 12 movement of the tongue |