The Heart, and adaptations of lungs for gas exchange

• Circulatory system


  Responsible for transporting oxygen, nutrients, hormones, and other essential substances throughout the body
• Heart


  • Powerful muscular organ that acts as a pump
• Blood vessels


  • Pathways or channels through which blood flows
• Heart chambers


  • Two atria (left and right)
  • Two ventricles (left and right)
• Blood flow through the heart

  1. Right side receives deoxygenated blood from the body and pumps it to the lungs for oxygenation

  2. Left side receives oxygenated blood from the lungs and pumps it to the rest of the body
• Types of blood vessels

  • Arteries
  • Veins
  • Capillaries
• Arteries


  Carry oxygenated blood away from the heart, except for the pulmonary artery which carries deoxygenated blood from the heart to the lungs. Pulmonary usually means related to lungs.
• Veins


  Carry deoxygenated blood back to the heart, except for the pulmonary vein which carries oxygenated blood from the lungs back to the heart
• Capillaries


  Tiny, thin-walled blood vessels that connect arteries to veins and allow the exchange of oxygen, nutrients, and waste products between the blood and the body's tissues
• Lungs


  • Remarkable organs that enable us to breathe and are adapted for gaseous exchange
• Gaseous exchange


  • Taking in oxygen from the air and releasing carbon dioxide, a waste product of respiration
• Adaptations of the lungs for gaseous exchange

  • Large surface area
  • Thin walls
  • Moist environment
  • Rich blood supply
• Large surface area of the lungs

  Achieved through the branching network of bronchi and bronchioles leading to alveoli, with alveoli surrounded by a dense network of capillaries
• Thin walls of alveoli and capillaries

  Enables easy diffusion of gases and reduces the diffusion distance
• Moist environment of alveoli

  Provides favorable conditions for gases to dissolve and diffuse efficiently, capturing oxygen and facilitating its movement into the bloodstream while enabling the removal of carbon dioxide
• Rich blood supply to the lungs

  Extensive network of capillaries surrounding the alveoli, ensuring a constant blood supply close to the air-filled alveoli to enhance the exchange of gases
• The heart and blood vessels work together to ensure that oxygenated blood is distributed efficiently throughout the body, while the lungs are specially adapted to facilitate the exchange of gases, allowing for the uptake of oxygen and the elimination of carbon dioxide