Advance Read: Respiratory and Circulatory Systems

Breathing Process

• Breathing delivers oxygen and removes carbon dioxide from the body
• Oxygen is carried in the blood to all cells and carbon dioxide is removed through exhalation

Mechanism of Breathing

• Inhalation:
  • Diaphragm tightens and moves downward to provide more space for lungs to expand
  • Intercostal muscles help widen the chest cavity
  • Air enters through the mouth and nose, passes through the windpipe, and into the lungs
• Exhalation:
  • Diaphragm moves upward and relaxes
  • Intercostal muscles relax and chest cavity decreases in size
  • Carbon dioxide is pushed out of the lungs and windpipe, and exits through the nose or mouth

Parts of the Respiratory System and Their Functions

Nasal Cavity (Nose and Mouth)

• Nose: normally used for inhalation, with tiny hairs (cilia) that act as a filter to catch dust and particles
• Mouth: used for breathing when more air is needed, especially during intense activity

Pharynx and Larynx

• Pharynx: the opening behind the nose and mouth, where air and food pass through
  • Lined with tissues called tonsils, which can partially obstruct the passage of air or food
  • Ends at the esophagus
• Larynx (voicebox):
  • Houses vocal chords and muscles used in producing sounds
  • Epiglottis found above the larynx, aids in closing it tightly to prevent food passage

Trachea and Bronchi

• Trachea (windpipe):
  • Tube responsible for directing air into and out of the lungs
  • Divides into two tubes at the end
• Bronchi:
  • Have several branches called bronchioles
  • Lead to air sacs called alveoli, where most gas exchange occurs

Lungs

• Cluster of bronchioles and alveoli, blood vessels, and elastic tissue
• Main function: to transfer oxygen into the bloodstream and excrete carbon dioxide into the air

Learn about the process of breathing, gas exchange, and the role of lungs in delivering oxygen and removing carbon dioxide from the body.