The figure shows the structure of the heart, according to the figure to answer: (can be used in the figure serial number or text answer)? (1) the heart is mainly composed of ______, divided into four

The figure shows the structure of the heart, according to the figure to answer: (can be used in the figure serial number or text answer)? (1) the heart is mainly composed of ______, divided into four chambers, which Solution: (1) the heart is mainly composed of myocardium, capable of contraction and diastole, to promote blood circulation in the heart and blood vessels in the pipeline system, is the power organ of the blood circulation; the thickness of the wall of the heart chambers is with the distance of the delivery of blood to the heart of the four chambers of the heart of the left ventricle contraction to deliver the blood of the longest distance, the wall is the thickest.

(2) The heart has four chambers: the left atrium, right atrium, left ventricle, right ventricle. Only the atria and ventricles are connected, the left and right sides of the heart are not connected, the left atrium is connected to the pulmonary veins, the right atrium is connected to the superior and inferior vena cava, the left ventricle is connected to the aorta, the right ventricle is connected to the pulmonary artery. Therefore, the venous vessels in the figure are c pulmonary vein, d superior vena cava and g inferior vena cava.

(3) between the atria and the ventricles, between the ventricles and the arteries, there are valves that can be opened and closed: these valves can only be opened in one direction: the atrioventricular valve can only be opened towards the ventricles, the arterial valve can only be opened towards the arteries. This ensures that blood can only flow in a certain direction: from the atria to the ventricles and from the ventricles to the arteries, but not backwards. In the figure, f is the atrioventricular valve between the right atrium and the right ventricle, which opens only to the right ventricle in D. e is the atrioventricular valve between the left atrium and the left ventricle, which opens only to the left ventricle in B.

(4) The pathway of blood circulation is shown in the figure: thus the direction of blood flow in the four parts of the structure: a aorta, A left atrium, B left ventricle, c pulmonary vein: A → B → a → c.

The answers are: (1) myocardium; left ventricle

(2) c pulmonary vein, d superior vena cava, g inferior vena cava

(3) D right ventricle; B Left ventricle

(4) A→B→a→c