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67 Cards in this Set
- Front
- Back
What does ECG stand for? |
- Electrocardiogram |
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What is an ECG/EKG? |
- 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? |
- 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? |
-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? |
- 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? |
-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? |
- 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? |
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? |
- Bradycardia is an extremely slow resting heart rate (<60 bpm). |
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What is tachycardia? |
- Tachycardia is an extremely high resting heart rate (>100 bpm). |
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Are they ever considered normal? |
- 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? |
- Ventricular fibrillation. |
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Describe what is happening in the condition know as AV node heart block. |
-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? |
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? |
- 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? |
- 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? |
The 2 categories of defense are innate and adaptive immunity. |
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Which cells are primarily involved in each? |
-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? |
-Innate immunity is our primary form of attack against a pathogen |
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Is it considered a specific or non-specific response? |
- It non-specifically attacks substances that are perceived as "non-self". |
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What is phagocytosis? |
-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 do this? |
- 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? |
- 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? |
- Adaptive immunity is immunity that is very specific to a particular antigen |
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What is a pathogen? |
- A pathogen is any substance capable of causing disease |
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Examples? |
- Examples are bacteria, viruses, or parasites. |
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Can any foreign molecule act as an antigen? |
-No, most antigens are proteins and must be of a certain size |
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What mechanisms are involved in local inflammation? |
-Both innate and adaptive. |
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What type of cells release histamine? |
- Histamine is released by mast cells (which are derived from basophils). |
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During inflammation, what changes occur in the local capillaries and what causes it? |
- 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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Why does the area swell? |
-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 |
-An electrical activity record of the heart, using surface electrodes (can be done on any animal) |
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Dipole |
-a separation of electrically charged regions |
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Sinoatrial (SA) node |
-a small, specialized region in the right atrial wall -the normal pacemaker of the heart |
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Internodal pathway |
-the pathway b/n the SA node and AV node |
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Atrioventricular (AV) node |
-a small bundle of specialized cardiac muscle cells located at the base of the right atrium near the septum |
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Bundle of His |
-a tract of specialized cells that originates at the AV node and enters the septum b/n the ventricles. |
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Purkinje fibers |
-small terminal fibers that extend from the bundle of His and spread throughout the ventricular myocardium much like small twigs of a tree branch |
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QRS complex |
-ventricular depolarization and atria repolarization |
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T-wave |
-ventricular repolarization |
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P-R interval |
-AV nodal delay (1/10th of a sec) |
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Arrhythmia |
-irregular heartbeats |
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Myopathes |
-damage to heart walls |
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Bradycardia |
-abnormal heart rate of <60/min |
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Tachycardia |
-abnormal heart rate of >100/min |
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Flutter |
-contraction rates of 200-300/min -arrhythmias detected on ECG |
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Fibrillation |
-myocardial cell depolarizations become asynchronous- the heart begins to quiver and no blood is pumped to the body |
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Electrical defibrillation |
-resynchronizes heart by depolarizing all cells at the same time |
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1st degree (primary) AV block (PR > 0.2 sec) |
-when conduction thru AV node > 0.2 sec -causes long P-R interval |
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2nd degree (secondary) AV block |
-when only 1 out of 2-4 atrial APs can pass to ventricles -causes P waves w/no QRS |
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3rd degree (complete) AV block |
-no atrial activity passes to ventricles -ventricles driven slowly by bundle of His or purkinjes |
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Self vs. Non-self |
-innate (nonspecific) immunity vs. adaptive (specific) immunity |
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Innate immunity |
-nonspecific -inherited as a part of structure of each organism -1st line of defense against invading pathogens -includes phagocytic cells, epithelial barriers, high acidity of gastric juice & fever |
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Adaptive immunity |
-specific -a function of lymphocytes & changes w/exposure |
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PAMP's (pathogen associated molecular patterms) |
-produced by only microorganisms -trigger phagocytosis |
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LPS (Lipopolysaccharides) -gram neg. |
-toll-like receptors (TLRs) on the innate immune cells that are responsible for recognizing the PAMP's on the microorganisms |
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Peptidoglycan – gram pos. |
-toll-like receptors (TLRs) on the innate immune cells that are responsible for recognizing the PAMP's on the microorganisms |
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Extravasation |
-how WBCs exit capillaries from blood (diapedesis) |
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Diapedesis |
-aka extravasation |
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Pyrogens |
-released by WBCs in response to endotoxins from Gm- bacteria |
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Antigen |
-molecules that elicit production of antibodies that specifically bind those antigens -usually foreign molecules to the body |
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Antibodies |
-recognize antigens of foreign microorganisms and cause an immune response |
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Opsinization |
-the promotion of phagocytic activity of neutrophils, macrophages & monocytes -caused by attachment of antibodies to antigens as inflammation progresses |
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Mast cells |
-release histamine, causing inflammatory response |
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Heparin |
-Prevents clots in the blood vessels before or after surgery or during certain medical procedures. Also treats certain blood, heart, and lung disorders and helps diagnose and treat certain bleeding disorders. This medicine is a blood thinner. |
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Histamine |
-cause the "flare and wheal" rxn of inflammation. Flare is the spreading flush/redness caused by some RBC's being able to enter or are getting closer to the skin surface; wheal is the elevated area due to edema |
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Leukotrienes |
-Leukotrienes use lipid signaling to convey information to either the cell producing them (autocrine signaling) or neighboring cells (paracrine signaling) in order to regulate immune responses. - Leukotriene production is usually accompanied by the production of histamine andprostaglandins, which also act as inflammatory mediators. -trigger contractions in the smooth muscles lining the bronchioles; their overproduction is a major cause of inflammation in asthma and allergic rhinitis. |