Heart Structure and Function

Heart Structure

• The heart is a muscular organ that pumps blood throughout the body
• It is divided into four chambers:
  1. Right atrium (receives deoxygenated blood from the body)
  2. Right ventricle (pumps blood from the right atrium to the lungs)
  3. Left atrium (receives oxygenated blood from the lungs)
  4. Left ventricle (pumps blood from the left atrium to the rest of the body)

Heart Function

• The heart pumps around 2,000 gallons of blood per day
• The heartbeat is regulated by the sinoatrial (SA) node, a group of cells in the right atrium
• The heartbeat is controlled by the autonomic nervous system, which stimulates the heart to beat faster or slower as needed

Blood Flow Through the Heart

• Deoxygenated blood enters the right atrium through the superior and inferior vena cavae
• Blood flows from the right atrium to the right ventricle through the tricuspid valve
• The right ventricle pumps blood through the pulmonary valve to the lungs
• Oxygenated blood returns to the heart through the pulmonary veins and enters the left atrium
• Blood flows from the left atrium to the left ventricle through the mitral valve
• The left ventricle pumps blood through the aortic valve to the rest of the body

Heart Wall Layers

• Epicardium: the outermost layer, a thin layer of connective tissue
• Myocardium: the middle layer, made up of cardiac muscle cells
• Endocardium: the innermost layer, a thin layer of epithelial tissue that lines the heart chambers

Heart Structure

• The heart is a muscular organ that pumps blood throughout the body
• It has four chambers: right atrium, right ventricle, left atrium, and left ventricle

Heart Chamber Functions

• Right atrium receives deoxygenated blood from the body through the superior and inferior vena cavae
• Right ventricle pumps blood from the right atrium to the lungs
• Left atrium receives oxygenated blood from the lungs through the pulmonary veins
• Left ventricle pumps blood from the left atrium to the rest of the body

Heart Function and Regulation

• The heart pumps around 2,000 gallons of blood per day
• The sinoatrial (SA) node, a group of cells in the right atrium, regulates the heartbeat
• The autonomic nervous system controls the heartbeat, stimulating it to beat faster or slower as needed

Blood Flow Pathway

• Deoxygenated blood flows from the body to the right atrium
• Blood flows from the right atrium to the right ventricle through the tricuspid valve
• Blood is pumped from the right ventricle to the lungs through the pulmonary valve
• Oxygenated blood returns from the lungs to the left atrium through the pulmonary veins
• Blood flows from the left atrium to the left ventricle through the mitral valve
• Blood is pumped from the left ventricle to the rest of the body through the aortic valve

Heart Wall Layers

• Epicardium is the outermost layer, a thin layer of connective tissue
• Myocardium is the middle layer, made up of cardiac muscle cells
• Endocardium is the innermost layer, a thin layer of epithelial tissue that lines the heart chambers