Breathing

• What substances can trigger asthma attacks?

  Pollen, dust mites, cigarette smoke
• What happens to the bronchioles during an asthma attack?

  They release histamines causing inflammation
• What do histamines do during an asthma attack?

  They cause epithelial cells to swell
• What is the effect of excess mucus in the bronchioles?

  It narrows the airways, making breathing difficult
• What are the two ways to treat asthma?

  • Bronchodilators relax muscle cells in bronchioles
  • Preventative steroids reduce airway sensitivity
• How much greater is the force of the first breath a baby takes compared to normal inhalation?

  15-20 times greater
• What role do surfactants play in the lungs?

  They prevent alveoli from collapsing
• When do full-term babies produce enough surfactant?

  By the 30th week of pregnancy
• What is the function of the nasal cavity?

  Warms and moistens incoming air
• How does the trachea assist in breathing?

  It is lined with epithelial cells and mucus
• What supports the trachea during breathing?

  Rings of cartilage
• What is the role of pleural membranes?

  They lubricate and cushion the lungs
• What causes air to move in and out of the lungs?

  Pressure changes in the thorax
• What is the diaphragm's role during inhalation?

  It contracts and moves down
• What happens to thoracic pressure during exhalation?

  It increases, forcing air out
• What are the adaptations of alveoli for gas exchange?

  • Thin walls (one cell thick)
  • Large surface area
  • Surrounded by capillaries for blood supply
  • Elastic tissues for stretching and recoil
• Why are lungs located inside the body?

  To prevent water loss and protect them
• What maintains a steep concentration gradient for gases in the alveoli?

  Constant blood flow through capillaries
• What is mass flow in the context of gas exchange?

  Bulk movement due to pressure differences
• What is the diameter range of alveoli for O2 exchange?

  200-300 µm
• What is the primary function of alveoli?

  Main sites of gas exchange in the body
• What is the role of collagen and elastin in alveoli?

  They provide structural support and elasticity
• How does the structure of alveoli facilitate gas exchange?

  Thin walls reduce diffusion distance
• What is the significance of a good blood supply to alveoli?

  It maintains concentration gradients for gases
• What happens to the air in the alveoli during gas exchange?

  O2 enters blood, CO2 exits
• Why is expiration considered a passive process?

  No muscular contraction is required for expiration.
• What are the two steps involved in normal respiration?

  1. Inhalation: Diaphragm contracts, intercostal muscles lift ribs.
  2. Exhalation: Diaphragm and intercostal muscles relax.
• What happens to the diaphragm and intercostal muscles during exhalation?

  Both relax to reduce lung volume.
• What is the role of the diaphragm during inhalation?

  It contracts downward to expand lung volume.
• What do the intercostal muscles do during inhalation?

  They contract and lift the ribs.
• What are the differences between inhalation and exhalation?

  • Inhalation: Diaphragm contracts, intercostal muscles contract, lung volume expands.
  • Exhalation: Diaphragm relaxes, intercostal muscles relax, lung volume reduces.
• What defines a passive process in the respiratory system?

  A process that does not require muscle energy.
• What is the role of the thoracic cavity during expiration?

  It recoils to compress the lungs.
• What are the features of passive and active expiration?

  • Passive Expiration:
  • Mechanism: Lung elasticity
  • Effort: No muscle effort
  • Role: Normal breathing
  • Active Expiration:
  • Mechanism: Muscle activity
  • Effort: Requires muscle energy
  • Role: Heavy breathing/coughing
• What distinguishes passive expiration from active expiration?

  Passive expiration requires no muscle effort.
• What happens to the diaphragm during passive exhalation?

  It relaxes, allowing lung volume to reduce.
• What happens to the intercostal muscles when you breathe in?

  They contract
• What is the effect of intercostal muscle contraction on the ribcage?

  It pulls the ribcage upwards
• How does the chest volume change when you breathe in?

  The chest increases in volume
• What happens to the diaphragm when you breathe in?

  It contracts and moves down