Human Circulatory System Quiz

Introduction to the Human Cardiovascular System

• The cardiovascular system comprises the heart, blood vessels, and blood.
• Its primary function is transporting nutrients and oxygen-rich blood throughout the body and returning deoxygenated blood to the lungs.

Components of the Cardiovascular System

• Blood
• Heart
• Blood Vessels

Blood

• Blood is composed of blood cells and plasma.
• Blood cells include:
  • Erythrocytes (red blood cells), which carry oxygen and carbon dioxide.
  • Leukocytes (white blood cells), part of the immune system.
  • Thrombocytes (platelets), essential for blood clotting.
• Plasma is the fluid portion of blood, primarily water with dissolved proteins, ions, nutrients, and waste products.

Heart

• The heart is a four-chambered, muscular organ about the size of a fist.
• Located superior to the diaphragm, slightly to the left of the midline, and anterior to the vertebral column, posterior to the sternum.
• The heart has four chambers: two atria and two ventricles.

Heart Valves

• Heart valves ensure one-way blood flow.
  • Atrioventricular (AV) valves (tricuspid and mitral/bicuspid valves) control blood flow between the atria and ventricles.
  • Semilunar valves (pulmonary and aortic valves) control blood flow out of the ventricles.
• When ventricles contract, AV valves close to prevent backflow into the atria.
• When ventricles relax, semilunar valves close to prevent backflow into the ventricles.

Pathway of Blood Through the Heart and Lungs

• Deoxygenated blood enters the right atrium.
• Blood flows through the tricuspid valve into the right ventricle.
• Blood is then pumped through the pulmonary semilunar valve to the lungs.
• Oxygenated blood returns to the left atrium through the pulmonary veins.
• Blood flows through the mitral/bicuspid valve into the left ventricle.
• Blood is pumped out of the heart through the aortic semilunar valve into the aorta.
• The aorta distributes oxygenated blood to the rest of the body.

Pulmonary Circulation

• Transports deoxygenated blood from the heart to the lungs and returns oxygenated blood to the heart.
• This is where oxygen enters the blood and carbon dioxide leaves the blood.

Systemic Circulation

• Transports oxygenated blood from the heart to the body and returns deoxygenated blood to the heart.
• It's a longer circuit than pulmonary circulation.
• Blood reaches all body parts.

Coronary Circulation

• Supplies blood to the heart muscle itself.

Blood Vessels

• Arteries carry oxygenated blood away from the heart.
• Capillaries facilitate the exchange of nutrients and gases between blood and tissues.
• Veins carry deoxygenated blood back to the heart.

General Structure of Blood Vessels

• Tunica intima (innermost layer)
• Tunica media (middle layer)
• Tunica adventitia (outermost layer)