Circulatory System 🫀

• The circulatory system transports nutrients, oxygen and wastes to and from cells'
• The blood becomes deoxygenated in the right atrium of the heart.
• The blood becomes oxygenated in the lungs and then returns to the heart.
• The pulmonary arteries carry deoxygenated blood from the heart to the lungs.
• The superior and inferior vena cava carries oxygenated blood.
• The hepatic portal vein carries blood to the liver from the intestines, spleen, pancreas and gallbladder.
• Veins have thinner walls than arteries and return blood back to the heart under low pressure.
• Capillaries are tiny vessels where gas exchange occurs between the blood and body cells.
• Venules are small vessels that collect blood from capillaries and join together to form larger veins.
• Arterioles control the flow of blood into capillaries by regulating their diameter.
• The right side of the heart receives deoxygenated blood from the body through the superior and inferior vena cava and pumps it into the lungs via the pulmonary trunk.
• The left side of the heart receives oxygenated blood from the lungs through the pulmonary veins and pumps it out to the rest of the body through the aorta.
• Atrial systole is the contraction of the atria, pushing blood into the ventricles. It lasts for 0.1 seconds.
• Atrial diastole is the relaxation of the atria before ventricular systole. It lasts for 0.7 seconds.
• The ventricular systole is when the ventricles contract and pump blood into the aorta. It lasts for 0.3 seconds.
• The ventricular diastole is when the ventricles relax and the ventricular walls are thinner. It returns blood to the heart in preparation for the next contraction. This phase lasts for 0.5 seconds.
• Blood pressure in the arteries is higher during the ventricular systole phase.
• Blood pressure is lowest during the ventricular diastole stage.
• The arteries and veins involved in pulmonary circulation is the pulmonary arteries and the pulmonary veins.
• The coronary arteries make up the systemic circulation.
• Arteries:

  • No valves
  • Elastic
  • Thick walls
  • Carry high blood pressure
  • Away from the heart
• Veins:

  • Thin walls
  • Inelastic
  • Often have valves
  • Carry low Blood pressure
  • Cary blood towards the heart