Cardiovascular and Lymphatic Systems: Diseases

Cardiovascular Diseases

Hypertension (High Blood Pressure): Blood pressure that exceeds normal ranges.

Arteriosclerosis: Hardening of the arteries and loss of elasticity; blood pressure rises, so hypertension may occur.

Atherosclerosis: Cholesterol plaque build-up in the internal walls of the arteries. This leads to the thickening of the affected area.

Aneurysm: Abnormal dilatation of a blood vessel, generally a main artery, which, when it ruptures, can cause death.

Varicose Veins: Abnormal dilatations of veins that can be observed easily. They are caused by the deterioration of venous valves.

Heart Attack: Lack of blood in the myocardium due to an obstruction of one of the heart’s coronary arteries.

Angina Pectoris: Lack of oxygen in the myocardium when exercise is carried out. This occurs due to plaque build-up in the coronary arteries.

Heart Failure (HF): The heart is unable to provide adequate blood flow for the body’s needs.

Endocarditis: Inflammation of the endocardium caused by a bacterial infection.

Anemia: A decrease in the number of red blood cells in the blood or a decrease in the quantity of the hemoglobin present in these cells.

Leukemia: An excessive increase in the number of abnormal white blood cells, as well as a decrease in the number of normal red blood cells.

Hemophilia: A hereditary disease that is characterized by the absence of certain proteins from the blood plasma that are needed for blood coagulation.

Thrombosis: The formation of a blood clot inside an artery.

Stroke: A serious life-threatening medical condition that happens when the blood supply to part of the brain is cut off.

Blood Types

• Type AB-positive: Called the “universal recipient” type because a person who has it can receive blood of any type.
• Type O-negative: Does not have any antigens. It is called the “universal donor” type because it is compatible with any blood type.

Functions of the Lymphatic System

1. To return excess interstitial fluid to the bloodstream, maintaining the volume of blood in the circulatory system.
2. To defend the body against infection.
3. To absorb lipids from the digestive system and to transfer them to the blood through lymphatic vessels called lacteals.

Circulation Summary

Pulmonary Circulation

The oxygen-depleted blood that enters the right atrium passes into the right ventricle through the tricuspid valve, where it is pumped through the pulmonary artery. This artery leads away from the heart and splits into two arteries, each carrying blood to a lung. A dense network of capillaries surrounds the alveoli, where gas exchange takes place. The capillaries turn into venules, which join together to form four pulmonary veins (two in each lung) that lead to the left atrium. From here, the blood flows through the mitral valve to the left ventricle, where systemic circulation begins.

Systemic Circulation

The blood starts in the left ventricle and flows along the aorta, which splits into arteries, arterioles, and then into capillaries. These lead to all body tissues and organs except the lungs. The blood in the capillaries provides cells with the oxygen and nutrients they need and takes away waste products (mainly carbon dioxide). It then returns via the venules, veins, and venae cavae, passing into the right atrium and then the right ventricle for pulmonary circulation to start again.