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66 Cards in this Set
- Front
- Back
What does ECG stand for?
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Electrocardiogram
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What is an ECG/EKG?
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It is an electrical record of the hearts electrical events.
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Are the axis of the heart and the major dipole of the heart related?
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The axis of the heart is a
calculation that is made by comparing the "view" of the dipole from two different leads. Using the comparison, this allows you to identify the major dipole direction. |
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What is the major electrical connection between the atria and the ventricles?
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The major electrical connection between the atria and the ventricles is the AV node (atrioventricular
node), without this connection there would be no electrical cross-talk between the atria and the ventricles. |
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What are the major events seen in an ECG, and what does each indicate?
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The p-wave corresponds to the initiation of the depolarization of the atrial contracting cells. The QRS complex corresponds to the initiation of the depolarization of the ventricular contracting cells and also has the atrial repolarization event buried in the signal. The t-wave corresponds to the initiation of the repolarization of the ventricular contracting cells.
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What are the normal time intervals of each segment of the ECG?
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P-R interval = 0.12-0.20sec; QRS complex = under 0.10 sec; Q-T interval under 0.38 sec
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What does axis of the lead refer to?
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The arrangement of the negative and positive electrodes of the lead.
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What 4 pieces of information, that we discussed in class, can you obtain from an ECG?
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1. Heart rate.
2. Presence of arrhythmias. 3. Presence of myopathes (ischemic areas). 4. Problems with the conducting system. |
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What is bradycardia?
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Bradycardia is an extremely slow resting heart rate (<60 bpm).
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What is tachycardia?
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Tachycardia is an extremely high resting heart rate (>100 bpm).
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Are bradycardia and tachycardia ever considered normal?
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Bradycardia normally occurs when we sleep, and also
well trained atheletes have resting heart rates that can be <60 bpm. At rest, tachycardia is not considered normal, but with exercise, heart rates will easily become >100 bpm. |
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What type of arrhythmia is life-threatening?
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Ventricular fibrillation
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Describe what is happening in the condition know as AV node heart block.
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Heart block is a condition in which the AV node begins to deteriorate (or die). As heart block progresses, the ventricles will slowly start to beat at the rate of the pacemaker potentials
of the Purkinje fibers |
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What characterizes each phase of AV node block?
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1st degree - longer than normal P-R interval; 2nd degree - not all atrial depolarization events sent to the ventricles, detected on the ECG by having some P-waves that do not have QRS
complexes following them; 3rd degree (complete) - when atria and ventricles are beating at completely different paces. |
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What are the pacemaker potential rates for the different conducting cells of the heart?
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The rates of the pacemaker cells are as follows: SA node =
~100 bpm, but because of parasympathetic dominance, it is slowed to~ 75-80 bpm; the AV node ~ 60 bpm; and the Bundle of His/Purkinje fibers ~20-40 bpm. |
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What events are seen in an ECG that correspond to a PVC?
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In an ECG, the events that occur with a PVC are 1. No p-wave. 2. Both an enlarged and spread out QRS complex. 3. A
compensatory pause. |
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What are the 2 categories of defense mechanisms in our bodies?
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The 2 categories of defense are
innate and adaptive immunity. |
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Which cells are primarily involved adaptive and innate immunity? .
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Innate immunity involves phagocytic cells, such as neutrophils and macrophages; adaptive immunity involves
lymphocytes (B and T-cells) |
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What is innate immunity?
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Innate immunity is our primary form of attack against a pathogen.
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Is innate immunity considered a specific or non-specific response?
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It non-specifically attacks substances that are perceived as "non-self".
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What is phagocytosis?
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Phagocytosis is the process in which a cell or a foreign substance in engulfed so that it can be degraded
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What types of cells perform phagocytosis?
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The cells which perform
phagocytosis are netrophils and monocytes/macrophages |
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What are the two terms that refer to the movement of WBC from the blood into the tissues? .
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Movement of WBC's our of the blood stream and into the tissues is called diapedesis or extravasation
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What is adaptive immunity?
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Adaptive immunity is immunity that is very specific to a
particular antigen |
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What is a pathogen? Examples?
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A pathogen is any substance capable of causing
disease. Examples are bacteria, viruses, or parasites |
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Can any foreign molecule act as an antigen?
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No, most antigens are proteins and must be of a certain size
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What mechanisms are involved in local inflammation?
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Both innate and adaptive
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What type of cells release histamine?
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Histamine is released by mast cells (which are derived from basophils).
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During inflammation, what changes occur in the local vessels and what causes it?
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Primarily due to the release of histamine, heparin, and prostaglandins from Mast cells, the vessels vasodilate, allowing more blood flow to the area, also, the
histamine causes the pores in the endothelial cells to enlarge, making the vessels more permeable. |
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During inflammation, why does the area swell?
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An area will swell at a site of inflamation because mast cells secrete heparin, histamine, prostaglandins, leukotrienes, cytokines, & TNF-a. All of these produce redness, swelling, pus, & pain. (The redness is from enhanced blood flow to the area, the swelling is from more fluid and cells entering the interstitial space,
the pus is from an accumulation of WBC’s that are engulfing the pathogen and sometimes dying from toxins produced by those pathogens, and pain is associated with more fluid in the interstitial space as well as activation of pain receptors by some of the chemicals produced by the pathogens). |
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Electrocardiogram
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An electrical activity record of the heart, using surface electrode, one region can momentarily be depolarized, and another region depolarized, and this depolarization can be recorded from the cells surface, can tell us Heart rate, arrhythmia’s, damage to heart walls (myopathes), damage to the conduction system
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Dipole
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Regions in the heart that are going to be depolarized and repolarized (spread of electrical activity), extended throughout the body and can be recorded at the surface using electrodes that contant the skin
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Sinoatrial Node
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A small specialized autorhythmic region in the right atrial wall of the heart that has the fastest rate of spontaneous depolarizations and serves as the normal pacemaker of the heart
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Internodal Pathway
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The pathway found between the SA node and the AV node that creates a temporary pause
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Atrioventricular Node
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A small bundle of specialized cardiac cells at the junction of the atria and ventricles that is the only site of electrical contact between the atria and ventricles
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Bundle of His
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A tract of specialized cardiac cells that rapidly transmits an action potential down the interventricular septum of the heart
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Purkinje Fibers
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Small terminal fibers that extend from the bundle of his and rapidly transmit an action potential throughout the ventricular myocardium
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QRS Complex
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Ventricular depolarization (atria repolarizing simultaneously)
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T Wave
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Ventricular repolarization
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PR Interval
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AV nodal delay, atrial cells contract, electrical activity and AV nodal delay, includes P wave
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Arrhythmia
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Abnormal heart rhythms, can be detected on an ECG
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Myopathes
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Damage to the heart walls
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Bradycardia
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Slower than normal heart rate <60/min
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Tachycardia
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Faster than normal heart rate >100/min
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Flutter
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Contraction rate can be between 200-300/min, life threatening, blood is flowing but at a small volume
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Fibrillation
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Contraction of myocardial cells is uncoordinated and pumping ineffective, life threatening, heart is shaking, and no blood flow
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Electrical Defibrillation
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Resynchronizes heart by depolarizing all cells at same time, given a shock because you want to depolarize all cells at the same time
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1st Degree (primary) AV Block
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Arrhythmias, PR > 0.2 sec when conduction through AV node >0.2 sec, causes long PR interval (longer delay of AV)
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2nd Degree (Secondary) Av Block
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Arrhythmias, Is when only one out of 2-4 atrial action potentials can pass to ventricles, causes P waves with no QRS
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3rd Degree (Complete) AV Block
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Arrhythmias, No atrial activity passes to ventricles, ventricles drive slowly by bundle of His or purkinjes
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Self vs Nonself
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Self belongs in the body, nonself does not and is a foreign, central theme of the immune system
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Innate Immunity
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Is nonspecific, inherited as part of structure of each organism, first line of defense against invading pathogens, includes not only phagocytic cells, but epithelial barriers,
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Adaptive Immunity
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Is specific, a function of lymphocytes and changes with exposure
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PAMP’s (pathogen associated molecular patterns)
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Patterns of molecules on outside of cell that help it be easily identifies as foreign, produced only by microorganisms and triggers phagocytosis
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LPS (Lipopolysaccharides)
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Gram negative type of pathogen associated molecular patterns (PAMP’s)
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Peptidoglycan
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Gram positive type of pathogen associated molecular patterns (PAMP’s)
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Extravasation
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A type of diapedesis that WBC’s exit capillaries by when ingesting pathogens
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Diapedesis
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A form of extravastion that WBC’s exit capillaries by when ingesting pathogens
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Pyrogens
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Released by WBC’s in response to endotoxin from gram negative bacteria that cause a thermostat reset and increases temperature, signaling molecule is given off by cytokines that resets hypothalamus, increase in temperature causes proteins in body to denature and enzymes to not work, also decreases number of bacteria dividing producing less bacteria for immune system to clean up
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Antigen
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Found on bacterial cells, a large complex molecule that triggers a specific immune response against itself when it gains entry into the body
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Antibodies
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Produced by B cells to fight against bacterial antigens, an immunoglobin produced by a specific activated B lymphocyte (plasma cell) against a particular antigen, binds with a specific antigen against which it is produced and promotes the antigenic invaders destruction by augmenting nonspecific immune responses already initiated against the antigen
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Opsinization
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Phagocytic activity of neutrophils, macrophages, and monocytes
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Mast Cells
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Cells located within connective tissue that synthesize, store, and release histamine, as during allergic responses
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Heparine
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A chemical released from mast cells that produce swelling, redness, warmth, pus and pain, recruit more leukocytes
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Histamine
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A chemical released from mast cells or basophils that brings about vasodilation and increased capillary permeability; important in allergic responses, creates swelling, redness, warmth, pus, and pain and recruits more leukocytes
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Leukotrienes
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A chemical released by mast cells that produce swelling, redness, warmth, pus and pain, and recruits more leukocytes
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