Basic ECG interpretation Exam Review Solution 100% Accurate
- The nurse should understand the conduction system of the heart, the process associated with
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monitoring through ECG interpretation, patient preparation for the 12-lead ECG, ECG findings,
interpretation, and patient management with specific heart rhythm conditions.
- The ECG uses electrodes attached to the patient's skin to record physiologic heart changes.
- Four properties of heart cells, automaticity, excitability, conductivity, and contractility, allow the
conduction system to start an electrical impulse, send it through the heart tissue, and stimulate muscle
contraction.
- Automaticity Ability to initiate an impulse spontaneously and continuously
Excitability Ability to be electrically stimulated
Conductivity Ability to transmit an impulse along a membrane in an orderly manner
Contractility Ability to respond mechanically to an impulse
- A normal cardiac impulse begins in the sinoatrial (SA) node in the upper right atrium. It spreads over
the atrial myocardium via interatrial and internodal pathways, causing atrial contraction, pumping blood
into the left and right ventricles. The impulse then travels to the atrioventricular (AV) node, through the
bundle of His, and down the left and right bundle branches. It ends in the Purkinje fibers, which transmit
the impulse to the ventricles.
- autonomic nervous system
the part of the nervous system that regulates involuntary body functions, including the activity of the
cardiac muscle, smooth muscles, and glands. It has two divisions: The sympathetic nervous system
accelerates heart rate, constricts blood vessels, and raises BP; the parasympathetic nervous system
slows heart rate, increases intestinal peristalsis and gland activity, and relaxes sphincters.
- vagus nerve
either of the longest pair of cranial nerves mainly responsible for parasympathetic control over the heart
and many other internal organs, including thoracic and abdominal viscera.
- parasympathetic nervous system
pertaining to the craniosacral division of the autonomic nervous system, consisting of the oculomotor,
facial, glossopharyngeal, vagus, and pelvic nerves. The actions of the parasympathetic division are
mediated by the release of acetylcholine and primarily involve the protection, conservation, and
restoration of body resources. Reactions to parasympathetic stimulation are highly localized and tend to
counteract the adrenergic effects of sympathetic nerves. Parasympathetic fibers slow the heart;
stimulate peristalsis; promote the secretion of lacrimal, salivary, and digestive glands; induce bile and
insulin release; dilate peripheral and visceral blood vessels; constrict the pupils, esophagus, and
bronchioles; and relax sphincters during micturition and defecation. Postganglionic parasympathetic
fibers extend to the uterus, vagina, oviducts, and ovaries in females and to the prostate, seminal
vesicles, and external genitalia in males, innervating blood vessels of pelvic organs in both sexes;
stimulation of these nerves causes vasodilation in the clitoris and labia minora and erection of the penis.
- sympathetic nervous system [Show Less]