Circulatory System — Key English Terminology

1.Right atrium receives blood from superior and inferior vena cava. Right ventricle pumps blood to the pulmonary arteries. Left atrium receives oxygenated blood from the pulmonary veins. Left ventricle pumps blood to the aorta and has the thickest wall.

右心房接收上下腔靜脈血液。右心室將血液送往肺動脈。左心房接收肺靜脈的含氧血。左心室將血液送往主動脈，壁最厚。

2.Tricuspid valve sits between right atrium and right ventricle. Bicuspid or mitral valve sits between left atrium and left ventricle. Pulmonary semilunar valve guards the right ventricle to pulmonary artery exit. Aortic semilunar valve guards the left ventricle to aorta exit.

三尖瓣位於右心房到右心室之間。二尖瓣，又稱僧帽瓣，位於左心房到左心室之間。肺動脈瓣位於右心室到肺動脈出口。主動脈瓣位於左心室到主動脈出口。

3.Conduction sequence: SA node, then AV node, then bundle of His, then bundle branches, then Purkinje fibers.

傳導順序：竇房結 SA node，然後房室結 AV node，然後乙氏束，然後左右束支，然後乾野氏纖維。

4.Sinoatrial SA node is the natural pacemaker, firing at sixty to one hundred beats per minute. Atrioventricular AV node delays conduction so atria finish contracting first; backup rate is forty to sixty.

竇房結 SA node 是天然節律器，放電速率 60 到 100 次每分鐘。房室結 AV node 延遲傳導，讓心房先收縮完；備援速率 40 到 60。

5.Why is the SA node the pacemaker? Because it has the fastest intrinsic firing rate, dominating the entire cardiac rhythm. If SA fails, AV takes over but slower.

為什麼 SA node 是 pacemaker？因為它自發放電速率最快，主導整個心臟節律。SA 故障時，AV 接管但較慢。

6.Pulmonary artery carries DEoxygenated blood — the only artery that does so. Pulmonary vein carries oxygenated blood — the only vein that does so. Aorta carries the most oxygenated blood. Vena cava carries deoxygenated blood.

肺動脈攜帶缺氧血——唯一攜帶缺氧血的動脈。肺靜脈攜帶含氧血——唯一攜帶含氧血的靜脈。主動脈氧合最高。腔靜脈攜帶缺氧血。

7.Exam trap: arteries and veins are defined by leaving or returning to the heart, not by oxygenation status.

考試陷阱：動脈與靜脈以離開或回到心臟定義，不是含氧或缺氧。

8.Full pathway: right atrium, right ventricle, pulmonary artery, lungs for gas exchange, pulmonary vein, left atrium, left ventricle, aorta, systemic circulation, vena cava, back to right atrium.

完整路徑：右心房、右心室、肺動脈、肺進行氣體交換、肺靜脈、左心房、左心室、主動脈、體循環、腔靜脈、回到右心房。

9.Artery: thick wall, elastic, smooth muscle — withstands high pressure. Capillary: single layer of endothelial cells — site of substance exchange. Vein: thin wall with valves — low-pressure return flow.

動脈：厚壁、彈性組織、平滑肌——承受高壓。微血管：單層內皮細胞——物質交換處。靜脈：薄壁有瓣膜——低壓回流。

10.Clotting cascade: vascular spasm, platelet plug, coagulation cascade with clotting factors, then fibrin mesh — prothrombin to thrombin to fibrinogen to fibrin.

凝血瀑布：血管收縮、血小板栓、凝血瀑布（凝血因子）、纖維蛋白網——凝血酶原到凝血酶到纖維蛋白原到纖維蛋白。

11.Vitamin K is essential cofactor for synthesizing clotting factors two, seven, nine, and ten. Deficiency causes bleeding tendency. Warfarin is a vitamin K antagonist.

維生素 K 是凝血因子 II、VII、IX、X 合成的必要輔因子。缺乏造成出血傾向。Warfarin 華法林是維生素 K 拮抗劑。