Systemic circulation route: right ventricle → pulmonary artery → pulmonary capillary network → pulmonary vein → left atrium

Pulmonary circulation route: left ventricle → aorta → arteries at all levels → capillary network of various organs in the body → veins at all levels → superior and inferior vena cava → right atrium

Blood circulation route: superior and inferior vena cava → right atrium → right ventricle → pulmonary capillary network → pulmonary veins → left atrium → left ventricle → aorta → capillaries of various organs throughout the body

1. Four chambers: left atrium, left ventricle, right atrium, right ventricle

2. There is a mitral valve between the left atrium and the ventricle; there is a tricuspid valve between the right atrium and the ventricle.

3. There is the aortic valve between the left ventricle and the aorta; there is the pulmonic valve between the right ventricle and the pulmonary artery.

4. The heart wall is divided into 3 layers, from outside to inside: epicardium, muscular layer, and endocardium.

5. The pericardial cavity contains a small amount of serous fluid for lubrication.

6. The coronary arteries are blood vessels that nourish the heart. They originate from the root of the aorta and have two left and right branches.

7. The left coronary artery is divided into the anterior descending branch and the circumflex branch, and is mainly responsible for the blood supply to the myocardium of the left atrium, left ventricular anterior wall, lateral wall and the first 2/3 of the interventricular septum.

8. The right coronary artery mainly supplies the right atrium, right ventricle, posterior wall of the left ventricle, the myocardium in the posterior 1/3 of the interventricular septum, the sinoatrial node, the atrioventricular junction, etc.

9. The cardiac conduction system includes: sinoatrial node, internodal bundle, atrioventricular node, His node, left and right bundle branches and their branches, and Purkinje fibers, which are responsible for the formation and conduction of normal cardiac impulses.

10. The sequence of excitation conduction in the heart: sinoatrial node → atrial muscle → atrioventricular bundle and left and right bundle branches → Purkinje fibers → ventricular muscle

11. In normal people, ventricular depolarization begins in the middle of the interventricular septum and depolarizes from left to right; then the left and right ventricular free walls depolarize from the endocardium to the epicardium.

12. The base of the left ventricle and the cone of the pulmonary artery of the right ventricle are the last parts of the ventricle to depolarize.

13. The physiological characteristics of cardiomyocytes include autonomy, conductivity, excitability, and contractility.

"Resistance vessels": arteries, whose main function is to transport blood vessels to tissues and organs. The walls of arteries have muscle fibers and elastic fibers, which can contract and relax under the action of various vasoactive substances, changing the resistance of peripheral blood vessels.

"Capacity blood vessels": Veins, whose main function is to collect blood from capillaries and return blood to the heart. They have a large capacity. About 60%-70% of the blood in the machine is stored in veins.

"Functional blood vessels": Capillaries, located between arterioles and venules, are distributed in a network. Their walls are composed of a single layer of endothelial cells and basement membrane. They are the place where blood and tissue fluid exchange substances.

Sympathetic nerve excitement: accelerated heart rate, enhanced myocardial contractility, peripheral vasoconstriction, increased vascular resistance, and elevated blood pressure

Parasympathetic nerve excitement: heart rate slows down, myocardial contractility weakens, peripheral blood vessels dilate, vascular resistance decreases, and blood pressure decreases

The humoral factors that regulate the circulatory system include renin, angiotensin, and the aldosterone system, which play an important role in regulating sodium and potassium balance, blood volume, and blood pressure.