Cardiovascular System Lecture Notes

Introduction

• Focus on the ATIT's version 7 human anatomy and physiology exam, specifically on the cardiovascular system.
• Understanding why the heart produces lub-dub sounds.

Blood: Composition and Function

• Misconception: Human blood is always red, varying in shade depending on oxygen concentration.
  • Diagrams use blue/red to show oxygen levels, not actual blood colors.
• Role: Maintains pH, temperature, osmotic pressure (homeostasis).
  • Transports hormones, nutrients, gases.

Components of Blood

• Plasma: Liquid portion; mixture of water, proteins, salts, lipids.
• Red Blood Cells: Transport gases; hemoglobin gives red color.
• White Blood Cells: Fight infections.
• Platelets: Aid in blood clotting.

Circulatory System

• Arteries: Carry oxygen-rich blood away from the heart (A for Away).
• Veins: Return oxygen-poor blood to the heart (Verb: Veins Efficiently Return Blood).
• Pulmonary Circulation: Exception; pulmonary arteries/veins carry blood with opposite oxygenation levels.
• Capillaries: Site of oxygen and carbon dioxide exchange with tissues.

Heart Structure

• Orientation: Right side is deoxygenated, left is oxygenated.
• Chambers:
  • Right atrium and ventricle (deoxygenated)
  • Left atrium and ventricle (oxygenated)
  • Mnemonic: Atria are on top, Ventricle are below (A before V alphabetically)
• Valves: Prevent backflow, separate chambers.

Blood Flow Through the Heart

1. Deoxygenated blood returns via superior/inferior vena cava.
2. Enters right atrium, then right ventricle via tricuspid valve.
3. Right ventricle pumps blood through pulmonary valve into pulmonary artery to lungs.
4. Oxygenated blood returns via pulmonary veins to left atrium.
5. Left atrium to left ventricle via mitral valve.
6. Left ventricle pumps blood through aortic valve into aorta, supplying body.
7. Coronary Circulation: Supplies heart via coronary arteries, returns deoxygenated blood via coronary veins.

Heart Electrical Conduction System

• Sinoatrial Node (SA): Primary pacemaker.
• Bachmann's Bundle: Transmits signals from SA node to left atria.
• Atrioventricular Node (AV): Delays signal to allow atrial contraction.
• Bundle of His: Splits into right and left bundle branches.
• Purkinje Fibers: Facilitate ventricular contraction.

Intrinsic Pacemakers

• SA Node: 60-100 BPM.
• AV Node: 40-60 BPM; acts if SA node fails.
• Purkinje Fibers: 20-40 BPM; last resort.

ECG Basics

• Isoelectric Line: Baseline without electrical activity.
• P Wave: Atrial depolarization.
• QRS Complex: Ventricular depolarization.
• T Wave: Ventricular repolarization.
• Atrial Repolarization: Hidden within QRS complex.

Blood Pressure

• Systolic Pressure: During heart contraction; indicates heart's effort.
• Diastolic Pressure: During relaxation; indicates arterial resistance.

Conclusion

• Blood pressure norms around 120/80 but vary with age and individual.
• Visit NurseChunkStar.com for additional resources.
• Interactive Q&A encourages deeper understanding.