biology: respiration

• What happens to the diaphragm muscles during inhalation?

  Diaphragm muscles contract and the diaphragm flattens downwards.
• What is the role of external intercostal muscles during inhalation?

  External intercostal muscles contract while internal intercostal muscles relax.
• How do the ribs move during inhalation and what is the effect on the thoracic cavity volume?

  The ribs move upwards and outwards, increasing the thoracic cavity volume.
• What happens to the air pressure in the lungs during inhalation?

  The air pressure in the lungs decreases as the volume increases.
• What causes air to be forced into the lungs during inhalation?

  The air pressure in the lungs becomes lower than the atmospheric pressure.
• What happens to the diaphragm muscles during exhalation?

  Diaphragm muscles relax and the diaphragm arches upwards.
• What is the role of internal intercostal muscles during exhalation?

  Internal intercostal muscles contract while external intercostal muscles relax.
• How do the ribs move during exhalation and what is the effect on the thoracic cavity volume?

  The ribs move downwards and inwards, decreasing the thoracic cavity volume.
• What happens to the sternum during exhalation?

  The sternum moves down to its original position.
• What happens to the air pressure inside the lungs during exhalation?

  The air pressure inside the lungs increases as the volume decreases.
• What causes air to be forced out of the lungs during exhalation?

  The air pressure inside the lungs becomes higher than the atmospheric pressure.
• What is the immediate effect of carbon monoxide on red blood cells?


  It reduces their ability to transport oxygen by binding irreversibly to haemoglobin.
• How does carbon monoxide affect oxygen supply to body cells?


  It prevents haemoglobin from binding to oxygen, leading to less oxygen supplied to body cells.
• What is the consequence of decreased oxygen supply to vital organs due to carbon monoxide?


  It can lead to organ failure, particularly in the heart and brain.
• What are the long-term effects of carbon monoxide exposure?


  It can cause breathlessness and increases the risk of organ failure.
• How does carbon monoxide contribute to cardiovascular issues?


  It increases the rate at which fats are deposited on arterial walls, raising the risk of blood clots and atherosclerosis.
• What immediate effect does nicotine have on the body?


  It releases more adrenaline, increasing heart rate and blood pressure.
• What are the long-term effects of nicotine on the arteries?


  It leads to the narrowing of arteries, increasing the risk of blood clots and heart disease.
• What immediate effect does tar have on the respiratory system?


  It causes excessive mucus production that constricts airways.
• How does tar affect breathing rate?


  It increases the breathing rate to take in more air.
• What are the long-term effects of tar on the respiratory system?

  • Paralyses cilia lining the air passages
  • Increased mucus production, trapping bacteria and dust
  • Higher risk of chronic bronchitis and emphysema
  • Carcinogenic, leading to uncontrolled cell division
  • Reduces efficiency of gas exchange by coating inner alveoli walls， decreasing SA：V
• How does tar affect the efficiency of gas exchange in the lungs?


  It reduces the surface area to volume ratio for gas exchange.
• What is a consequence of tar paralyzing the cilia in the air passages?

  Dust trapped mucus cannot be removed, leading to lung infections.
• What health risks are associated with the excessive mucus production caused by tar?


  It increases the risk of chronic bronchitis and emphysema.
• How does tar contribute to lung infections?


  By trapping more bacteria and dust due to increased mucus production.
• What is chronic bronchitis characterized by?


  Inflamed epithelium lining the air passages
• What happens to mucus secretion in chronic bronchitis?


  Excessive mucus is secreted by the epithelium’s gland cells
• How do irritants affect cilia in chronic bronchitis?


  Cilia are paralyzed by irritants, dust trapped mucus cannot be removed
• What are the symptoms of chronic bronchitis?


  • Blocked airways
  • Breathing difficulties
  • Persistent coughing
  • Increased risk of lung infections
• What is a key symptom of emphysema related to bronchitis?


  Persistent and violent coughing
• What happens to the partition walls between alveoli in emphysema?


  They break down, decreasing surface area for gas exchange
• How does emphysema affect lung elasticity?


  Lungs lose elasticity and become inflated with air
• What are the symptoms of emphysema?


  • Breathing difficulties
  • Wheezing
  • Breathlessness
• What is lung cancer characterized by?


  Uncontrolled cell division
• chronic bronchitis

  • epithelium lining the air passages become inflamed
  • excess mucus is secreted by the epithelium
  • cilia is paralysed by tar and irritants
  • dust trapped mucus cannot be removed
  • air ways are blocked
• emphysema

  • due to prolonged persistent and violent coughing of chronic bronchitis
  • partition walls between alveoli break down, decreasing surface area to volume ratio for gas exchange
  • reduces efficiency of gas exchange between the alveoli and the blood in the capillaries
  • lungs lose elasticity