Биофизика курсымен қалыпты физиология кафедрасы
cm The distance from the left point in front of the ear to the right point in front of the ear - 33 cm
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- Задание №5.
| 40 cm
The distance from the left point in front of the ear to the right point in front of the ear - 33 cm The "10" and "20" refer to the fact that the actual distances between adjacent electrodes are either 10% or 20% of the total front–back or right–left distance of the skull. For example, a measurement is taken across the top of the head, from the nasion to inion. Most other common measurements ('landmarking methods') start at one ear and end at the other, normally over the top of the head. Nasion to Inion: the nasion is the distinctly depressed area between the eyes, just above the bridge of the nose, and the inion, is the crest point of back of the skull, often indicated by a bump (the prominent occipital ridge, can usually be located with mild palpation). Marks for the Z electrodes are made between these points along the midline, at intervals of 10%, 20%, 20%, 20%, 20% and 10%. The second main line connects the ear canals and passes through the vertex. Along this line, the location of the midtemporal leads (lat. Temporalis, T3 and T4) is determined at 10% of this distance from the ear canals. The remaining electrodes along this line (lat. Centralis, C3, Cz and C4) are located at equal distances from each other, amounting to 20% of the length of this line Задание №5. Draw a schematic diagram of the passage of an excitation wave through t he heart muscle. A normal tracing shows the P wave, QRS complex, and T wave. Also indicated are the PR, QT, QRS, and ST intervals, plus the P-R and S-T segments. The PR segment begins at the end of the P wave and ends at the beginning of the QRS complex. The PR interval starts at the beginning of the P wave and ends with the beginning of the QRS complex. The PR interval is more clinically relevant, as it measures the duration from the beginning of atrial depolarization (the P wave) to the initiation of the QRS complex. Since the Q wave may be difficult to view in some tracings, the measurement is often extended to the R that is more easily visible. Should there be a delay in passage of the impulse from the SA node to the AV node, it would be visible in the PR interval. Figure 8 correlates events of heart contraction to the corresponding segments and intervals of an ECG. жүктеу/скачать 0,71 Mb. Достарыңызбен бөлісу:
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