Understanding Blood Vessels and Blood Types

In the human circulatory system, arteries typically carry oxygenated (pure) blood away from the heart to the body, while veins carry deoxygenated (impure) blood back to the heart. However, there is one major exception to this rule.

Step 1: Identify the Standard Function of Arteries

Most arteries carry oxygen-rich blood. For example:

• The Aorta carries oxygenated blood to the body.
• The Coronary artery supplies oxygenated blood to the heart muscle itself.
• The Subclavian artery carries oxygenated blood to the arms.
• The Hepatic artery carries oxygenated blood to the liver.

Step 2: Recognize the Exception

The Pulmonary Artery is the exception. It is the only artery in the body that carries deoxygenated (impure) blood. Its function is to transport blood from the right ventricle of the heart to the lungs, where carbon dioxide is removed, and oxygen is picked up.

Step 3: Analyze the Given Options

• Subclavian artery: Carries oxygenated blood.
• Coronary artery: Carries oxygenated blood.
• Pulmonary artery: Carries deoxygenated (impure) blood.
• Hepatic artery: Carries oxygenated blood.

Final Answer

The artery that carries impure blood is the Pulmonary artery.

Related Topics & Formulae

Key Concepts in Circulatory System

Double Circulation: The human heart has a double circulatory system, meaning blood passes through the heart twice to complete one full cycle.

1. Pulmonary Circulation: The path of blood from the heart to the lungs and back.

   Pathway: Right Ventricle $\to$ Pulmonary Artery $\to$ Lungs $\to$ Pulmonary Vein $\to$ Left Atrium

2. Systemic Circulation: The path of blood from the heart to the rest of the body and back.

   Pathway: Left Ventricle $\to$ Aorta $\to$ Body $\to$ Vena Cava $\to$ Right Atrium

Important Formulae (Blood Flow & Pressure)

Cardiac Output (CO): The volume of blood pumped by the heart per minute.

$CO=HR\times SV$
Where: $HR$ = Heart Rate (beats/min), $SV$ = Stroke Volume (liters/beat)

Blood Pressure (BP): The pressure exerted by circulating blood on the walls of blood vessels. It is measured as systolic pressure over diastolic pressure (e.g., 120/80 mmHg).