Understanding the Human Circulatory System and Cardiovascular Health

Human Circulatory System: Double Circulation

The human circulatory system performs double circulation, meaning that the blood passes through the heart twice in order to complete a full circuit. The two loops are completely separate from one another, which prevents the mixing of deoxygenated blood.

• Blood passes through the lungs.
• All the organs receive blood that is equally rich in oxygen and nutrients.

Right Half of the Heart

• Vena cavae carry blood back to the heart.
• Blood enters through the right atrium and moves to the right ventricle.
• Blood exits through the pulmonary artery and goes to the lungs.

Left Half of the Heart

• Pulmonary veins bring blood from the lungs to the heart.
• Blood enters through the left atrium and moves to the left ventricle.
• Blood exits the heart through the aorta and goes toward each of the body's organs.

Heart Valves: Ensuring Unidirectional Blood Flow

Atrioventricular Valves

These valves link each atrium with the ventricle directly beneath it, on the same side of the heart. These valves open during atrial contraction as the blood flows from the atrium to the ventricle and then close during ventricular contraction to prevent the blood from flowing backward.

Semilunar Valves

These valves link each ventricle to its corresponding artery and are known as the pulmonary valve and the aortic valve. During ventricular contraction, these valves open, allowing blood to flow out of the heart and into the arteries, but they close when the heart relaxes to prevent blood from flowing back into the heart.

Pulmonary and Systemic Loops: Key Differences

What is the difference between the pulmonary and systemic loops of the cardiovascular system? The systemic circuit carries oxygenated blood from the heart around the body then carries the deoxygenated blood from the body back to the heart. The pulmonary circuit transports blood between the heart and the lungs.

Cardiovascular Diseases: A Closer Look

The diseases that affect the blood vessels and the heart are called cardiovascular diseases.

Blocked Arteries

The obstruction of an artery is caused by the accumulation of lipids, such as cholesterol, on the interior wall. When this occurs, the internal diameter of the artery is reduced, and its internal surface becomes uneven or irregular. This process causes atherosclerosis, which is when the arterial wall loses its elasticity and hardens.

Myocardial Infarction

• Atherosclerosis can lead to the formation of blood clots, which are known as thrombi.
• If the clot blocks essential blood vessels in the heart muscle itself, part of the heart can fail to receive the nutrients and oxygen it needs.
• This can result in tissue death in the affected region of the heart muscle.
• This process or condition is known as acute myocardial infarction, commonly referred to as a heart attack.
• If the artery is only partially blocked, it causes pain, known as angina pectoris.

Anemia

Anemia is a condition in which the blood has low hemoglobin levels. Normally, this is caused by insufficient iron, an essential component of hemoglobin. People suffering from this get tired easily and have low energy levels.

Leukemia

Leukemia is a type of cancer that affects the bone marrow, the tissue that produces the blood cells.

Recommendations for Cardiovascular Health

Recommendations: Do not use tobacco products, minimize consumption of animal fat and refined sugars, and exercise regularly.