The Mammalian Heart: Structure and Function | 哺乳动物心脏的结构与功能

📚 The Mammalian Heart: Structure and Function | 哺乳动物心脏的结构与功能

In IGCSE Biology (Edexcel), specification point 2.61 asks you to understand how the structure of the mammalian heart is adapted to its function. The heart is a muscular pump that sends blood to the lungs and around the body, and every structural feature—from chamber wall thickness to the orientation of valves—helps it perform this task efficiently.

在 Edexcel IGCSE 生物中，考点 2.61 要求你理解哺乳动物心脏的结构如何适应其功能。心脏是一个肌肉泵，将血液输送到肺部和全身；从腔壁厚度到瓣膜方向，每一个结构特征都有助于它高效完成这一任务。

1. Location and Overall Function | 位置与总体功能

The mammalian heart lies in the thoracic cavity, between the two lungs, with its apex pointing slightly to the left. It is enclosed in a protective membrane called the pericardium.

哺乳动物的心脏位于胸腔内、两肺之间，心尖稍向左下方。它被一层称为心包的保护膜包绕。

Its function is to maintain a continuous circulation of blood. Oxygen-poor blood is sent to the lungs to pick up oxygen, while oxygen-rich blood is driven around the body to deliver glucose and oxygen to respiring tissues.

它的功能是维持持续不断的血液循环。含氧较少的血液被送往肺部获取氧气，而富含氧气的血液被输送到全身，为呼吸组织提供葡萄糖和氧气。

2. Four Chambers | 四个腔室

The heart is divided into four chambers: left and right atria (upper chambers) and left and right ventricles (lower chambers). The atria collect blood returning to the heart, while the ventricles pump blood out of the heart.

心脏分为四个腔室：左心房、右心房（上部腔室）和左心室、右心室（下部腔室）。心房收集回流心脏的血液，心室则将血液泵出心脏。

The right atrium receives deoxygenated blood from the body through the vena cava. The right ventricle pumps this blood to the lungs through the pulmonary artery.

右心房通过腔静脉接收来自全身的去氧血。右心室通过肺动脉将这血液泵向肺部。

The left atrium receives oxygenated blood from the lungs through the pulmonary veins. The left ventricle pumps oxygenated blood to the whole body through the aorta.

左心房通过肺静脉接收来自肺部的富氧血。左心室通过主动脉将富氧血泵向全身。

A thick muscular wall, the septum, separates the right and left sides, preventing oxygenated and deoxygenated blood from mixing.

厚实的肌肉隔膜（室间隔）将心脏左右两侧分开，防止富氧血与

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