Cardiovascular System

Overview of the human cardiovascular system

The cardiovascular system, also known as the circulatory system, is an organ system that permits blood to circulate and transport nutrients, oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH, and maintain homeostasis.

Structure

The cardiovascular system consists of the heart, blood vessels, and blood. It is a closed system that circulates blood throughout the body.

Heart

The heart is a muscular organ located in the thoracic cavity. It is responsible for pumping blood through the blood vessels. The heart has four chambers: two atria and two ventricles. The right side of the heart pumps deoxygenated blood to the lungs via the pulmonary circulation, while the left side pumps oxygenated blood to the rest of the body via the systemic circulation.

Blood Vessels

Blood vessels are the conduits through which blood flows. They include:

• Arteries: Vessels that carry blood away from the heart. They have thick, elastic walls to withstand high pressure.
• Veins: Vessels that carry blood back to the heart. They have thinner walls and often contain valves to prevent backflow.
• Capillaries: Microscopic vessels where the exchange of gases, nutrients, and waste occurs between blood and tissues.

Blood

Blood is a specialized bodily fluid that delivers necessary substances to the body's cells and transports waste products away. It consists of:

• Red blood cells: Carry oxygen from the lungs to the body and carbon dioxide from the body back to the lungs.
• White blood cells: Part of the immune system, defending the body against infection.
• Platelets: Involved in blood clotting.
• Plasma: The liquid component that carries cells, nutrients, hormones, and waste products.

Function

The primary function of the cardiovascular system is to transport nutrients, gases, and waste products around the body. It plays a crucial role in maintaining homeostasis by regulating temperature, pH, and fluid balance.

Circulatory Pathways

The cardiovascular system has two main circulatory pathways:

• Pulmonary circulation: Carries deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium.
• Systemic circulation: Carries oxygenated blood from the left ventricle to the body and returns deoxygenated blood to the right atrium.

Clinical Significance

Diseases of the cardiovascular system are among the leading causes of death worldwide. Common conditions include:

• Hypertension: High blood pressure, which can lead to heart disease and stroke.
• Coronary artery disease: Narrowing or blockage of the coronary arteries, often leading to myocardial infarction (heart attack).
• Heart failure: A condition where the heart cannot pump enough blood to meet the body's needs.
• Arrhythmias: Abnormal heart rhythms that can affect the heart's ability to pump effectively.

Also see

• Respiratory system
• Lymphatic system
• Endocrine system
• Nervous system