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血壓、心電圖與週圍循環操作步驟
生物醫學工程學系 邱文泰
102.10.29
Cardiac anatomy and flow patterns
Pulmonary artery
Superior vena cava
Pulmonary vein
Right atrium
Left atrium
Inferior vena cava
Left ventricle
Right ventricle
Conducting system of the heart
AV node
Hiss
SA node
Cardiac excitation cycle (1)
Sinoatrial node
Atrioventricular node
Cardiac excitation cycle (2)
Electrocardiography (ECG) = Electrocardiogram
An ECG records extracellular potentials using electrodes adhered to the body surface.
Sinoatrial node
Electrocardiogram (ECG) limb leads
(1)
(2)
(3)
Bipolar limb leads: three bipolar limb leads
Augmented limb leads: three unipolarl eads
Precordial (chest) leads:
Precordial (chest) leads
The electrocardiogram
60-100 ms
80-100 ms
Isoelectric line
Ventricular
depolarization
Atrial depolarization
SA node
Ventricular
repolarization
Papillary muscle
repolarization
AV node

Bundle of His
120-200 ms
300-430 ms
Q wave: the intraventricular septum
R wave: the apex and the free walls
S wave: the region near the base
Sequence of cardiac excitation
R
T
P
Q
S
Heart sounds
Atrial contraction
Blood rushing into the LV
A2
P2
Heart murmurs
Heart murmurs are sounds associated with turbulent blood flow.
(1) Stiffening and stenosis of the aortic and pulmonary valves
obstruct blood flow and cause systolic ejection murmurs.
(2) Mitral and tricuspid insufficiency allows blood to flow backward
from ventricle to atrium during systole.
(3) Incompetent aortic and pulmonary valves cause diastolic murmurs.
Types of blood vessels
Blood vessel structure
Collagen fibers
With resting tone
Capillaries & venules without elastic fibers
Vascular smooth muscle cells (VSMCs)
Blood velocity and vessel cross-sectional area
across the systemic vasculature
50 cm/s
4 cm2
4000 cm2
< 1 mm/s
Resistance vessels
Elastic arteries
Perfusion pressures across the systemic vasculature