The preload of the ventricular muscle refers to

The clinical manifestations of ventricular preload and ventricular afterload are very similar, because the muscles on the ventricles mainly have the functions of relaxation and contraction. If preload occurs, the patient's heart contraction will be hindered to a certain extent. At this time, the patient will feel dyspnea and is very likely to develop hypertension and cardiovascular and cerebrovascular diseases. So what does ventricular preload mean?

The preload of the ventricular muscle refers to the resistance encountered by the myocardium before contraction, also known as volume load. It is the ventricular end-diastolic volume or the ventricular wall pressure at the end of diastole, that is, the preload of the ventricular muscle, which is related to the venous return. Within a certain range, as venous return increases, the anterior load and afterload will increase, which is common in patients with mitral valve and aortic regurgitation. Preload is an important factor in regulating stroke volume. When preload increases, myocardial contractility will increase and stroke volume will also increase. Long-term increase in preload will cause compensatory ventricular dilation and weakened contractility, leading to heart failure.

Preload: The resistance or load encountered by the myocardium before it contracts. That is, the volume or pressure at the end of ventricular diastole. It is related to venous return. Within a certain range, as venous return increases, preload increases. When the mitral valve or aortic valve is incompletely closed, the left ventricular end-diastolic volume or pressure increases and the preload also increases. Afterload: It is the resistance or load encountered after myocardial contraction, also known as pressure load. Aortic pressure and pulmonary artery pressure are the afterload of the left and right ventricles, respectively. Hypertension and valvular stenosis often increase the afterload of the ventricular muscle.

1. What are the preload and afterload of ventricular muscle? What is the effect on myocardial contraction?

(1) Myocardial preload: refers to the resistance or load encountered before the myocardium contracts. Therefore, the volume or pressure at the end of ventricular diastole is the preload of the ventricular muscle. It is related to venous return. Within a certain range, venous return increases and preload increases. =When the cusp valve or aortic valve is incompletely closed, the volume or pressure of the left ventricle at the end of diastole increases, and the preload also increases.

(2) Myocardial afterload: refers to the resistance or load encountered after myocardial contraction. The fork is called pressure load. Aortic pressure and pulmonary artery pressure are the afterload of the left and right ventricles. Hypertension and valvular stenosis often increase the afterload of the ventricular muscle and increase the burden on the heart. Clinically, vasodilators are used to reduce the afterload and thus relieve the burden on the heart in some patients with heart failure.

2Why is hypertension diagnosed mainly based on diastolic blood pressure?

The national hypertension standard stipulates that: any diastolic blood pressure that exceeds

Over 12 67kPa (95mmHg), regardless of its systolic blood pressure. All were classified as hypertension. There are two reasons to diagnose hypertension based on diastolic blood pressure;

(1) The average dynamic blood pressure is close to the diastolic blood pressure, which is equal to the diastolic blood pressure plus 1/3 of the pressure, and is much lower than the systolic blood pressure. The normal value is 9 33~13 33kF'a (70~100mmHg).

(2) The main factors affecting blood pressure are cardiac output and peripheral resistance. Cardiac output

To affect systolic blood pressure, peripheral resistance will only continue to increase when small arteries are sclerotic, and increased peripheral resistance will lead to increased diastolic blood pressure. therefore. Increased diastolic blood pressure may reflect arteriolar stiffness.

What are the physiological functions of potassium?

(1) Participate in the metabolism of sugar and protein in cells. (2) Maintain intracellular osmotic pressure and regulate acid-base balance. (3) Participates in the formation of resting potential, which is the equilibrium potential of potassium.