How the Normal Heart Works

Overview

• The heart is a vital muscular organ responsible for circulating blood throughout the body.
• Located in the center of the chest, it functions continuously, even during sleep.
• The heart and blood vessels constitute the cardiovascular system, essential for delivering oxygen and nutrients.
• Blood picks up oxygen in the lungs, then circulates through the body via the heart.

Structure of the Heart

• Two-sided Pump:
  • Consists of the right and left sides.
  • Contains four chambers: two atria (upper) and two ventricles (lower).
• Chambers:
  • Right atrium and ventricle pump oxygen-poor blood to lungs.
  • Left atrium and ventricle pump oxygen-rich blood through the body.
• Septa (Septa/Septum):
  • Divide the heart into two sides, preventing blood mix.

Heart Valves

• Tricuspid Valve: Between right atrium and right ventricle.
• Pulmonary Valve: Between right ventricle and pulmonary artery.
• Mitral Valve: Between left atrium and left ventricle.
• Aortic Valve: Between left ventricle and aorta.

Blood Circulation Process

• Major Veins & Arteries:
  • Superior and Inferior Vena Cava: Carry oxygen-poor blood to right atrium.
  • Blood flows through tricuspid valve to right ventricle.
  • Right ventricle pumps blood to lungs via pulmonary valve and artery.
  • Pulmonary Veins: Bring oxygen-rich blood to left atrium.
  • Blood flows through mitral valve to left ventricle.
  • Left ventricle pumps blood into aorta via aortic valve.
  • Blood distributed throughout the body, delivering oxygen.

Heart's Control System

• Heartbeat initiated by electrical impulse from sinus node, the heart's pacemaker.
• Sinus node located in the top right atrium.
• Electrical signals cause atria and ventricles to contract, pumping blood.

Transition after Birth

• Ductus Venosus: Stops carrying blood post-birth, begins constricting in hours/days.
• First breath expands lungs, reduces pressure, promotes blood flow to lungs.
• Ductus Arteriosus: Constricts, fully closes within 24-48 hours, blood directed to lungs.
• Foramen Ovale: Closes as left atrium pressure increases after birth.

Contact Information

• For more details, contact the Cardiac Center at Children's Hospital of Philadelphia.
• Outpatient appointments and inquiries: 215-590-4040.
• Second opinions and referrals: 267-426-9600.
• Visit Cardiac Center for more information.