Lecture Notes: The Circulatory System

Overview of the Circulatory System

• Also known as the cardiovascular system.
• An organ system made up of the heart, blood vessels, and blood.
• Function: Transport substances around the body.
  • Blood carries oxygen, nutrients, cells, and waste products.
  • Blood vessels direct the blood flow.
  • The heart pumps blood to maintain flow through vessels.

Double Circulatory System

• Composed of two separate circuits:
  • Pulmonary Circuit:
    • Blood flows from the heart to the lungs and back to the heart.
  • Systemic Circuit:
    • Blood flows from the heart to body tissues and back to the heart.
• The process repeats continuously to maintain circulation.

Structure of the Heart

• The heart is a muscular organ functioning as a pump.
• Four Chambers:
  • Atria (upper chambers):
    • Right Atrium
    • Left Atrium
  • Ventricles (lower chambers):
    • Right Ventricle
    • Left Ventricle
• Atrioventricular Valves:
  • Ensure one-way blood flow from Atria to Ventricles.

Orientation of the Heart

• The left and right sides of the heart are labeled as if viewed from the front (someone else's heart).
• Left side (our right), Right side (our left).
• Differences in Ventricle Walls:
  • Left Ventricle has a thicker wall to pump blood throughout the body.
  • Right Ventricle pumps only to the lungs.

Major Blood Vessels

• Vena Cava (largest vein):
  • Carries deoxygenated blood from the body to the right atrium.
• Pulmonary Artery:
  • Carries deoxygenated blood from the right ventricle to the lungs.
• Pulmonary Vein:
  • Carries oxygenated blood from the lungs to the left atrium.
• Aorta (largest artery):
  • Carries oxygenated blood from the left ventricle to the body.

Coronary Circulation

• Heart muscle requires its own supply of oxygenated blood.
• Coronary Arteries:
  • Branch off the aorta to supply the heart.
  • Blockages can lead to coronary artery disease or a heart attack.

Additional Resources

• Videos, questions, flashcards, and exam materials available at Cognito.org.
• Options for tracking progress and preparing for exams.