Introduction to the Circulatory System

Overview

• Questions to ponder:
  • How is glucose transported after digestion?
  • How does oxygen and carbon dioxide transport occur?
• The circulatory system is crucial for these processes.
• This lecture is an introduction; the topic is covered in depth in extensive textbooks.

Blood Basics

• Blood is the medium for transporting glucose and gases.
• Misconceptions:
  • Human blood is always red, shades vary with oxygen levels.
  • Veins appear blue/green due to skin optics, not their actual color.

Functions of Blood

• Maintains pH, temperature, osmotic pressure for homeostasis.
• Transports hormones, nutrients, gases.

Components of Blood

• Plasma: Liquid portion with water, proteins, salts, lipids.
• Cellular Components:
  • Red Blood Cells: Transport gases, contain hemoglobin (red color).
  • White Blood Cells: Fight infections.
  • Platelets: Help blood clotting.

Heart Anatomy

• Divided into oxygenated and deoxygenated partitions.
• Arteries carry blood "away" from the heart (usually oxygen-rich).
• Veins carry blood "to" the heart (usually oxygen-poor).
• Capillaries: Site for gas exchange with organs and tissues.

Heart Structure

• Right Side: Pumps deoxygenated blood.
• Left Side: Pumps oxygenated blood.
• Chambers:
  • Right Atrium & Ventricle
  • Left Atrium & Ventricle
• Valves: Prevent backflow and separate chambers.

Pathway of Blood through the Heart

1. From toe: Deoxygenated blood via inferior vena cava to right atrium.
2. Right Atrium: Contracts, blood moves through tricuspid valve to right ventricle.
3. Right Ventricle: Contracts, blood goes through pulmonary valve to pulmonary artery.
4. Lungs: Blood becomes oxygenated.
5. Pulmonary Vein: Oxygenated blood returns to left atrium.
6. Left Atrium: Contracts, blood moves through mitral valve to left ventricle.
7. Left Ventricle: Contracts, blood goes through aortic valve into aorta.
8. Aorta: Distributes oxygenated blood throughout the body.

Coronary Circulation

• Coronary Arteries: Branch off aorta to supply heart with blood.
• Coronary Veins: Return deoxygenated blood to right atrium.

Heartbeat Coordination

• Cardiac Cycle: Coordinated heart contractions and relaxations.
• Heart beats over 100,000 times/day.

Heart Conditions

• Atrial Septal Defect: Opening in septum allows blood mixing.
  • Can lead to abnormal heartbeat, stroke, heart failure.
  • Treatment options include medication and surgery.

Conclusion

• Cardiovascular conditions are an area of ongoing research and advancement.
• Encouragement to explore further in cardiology.