Physiology Week 12 Flashcards
(15 cards)
What happens during inspiration?
The diaphragm contracts, the ribcage expands, and air flows into the lungs due to lower pressure.
What happens during expiration?
The diaphragm relaxes, the ribcage moves down, and air is pushed out due to higher pressure.
How do muscles help in breathing?
Diaphragm and external intercostals contract for inspiration; relaxation causes expiration.
What additional muscles help in forced breathing?
Sternocleidomastoid, scalenes, and abdominal muscles.
How does quiet breathing differ from forced breathing?
Quiet breathing is passive; forced breathing uses extra muscles for deeper breaths.
What is alveolar (intrapulmonary) pressure?
Pressure inside the alveoli that changes with breathing.
What is intrapleural pressure?
Always negative pressure in the pleural cavity that prevents lung collapse.
What is external respiration?
Gas exchange between alveoli and blood (O₂ in, CO₂ out).
What is internal respiration?
Gas exchange between blood and tissues (O₂ to cells, CO₂ to blood).
How does partial pressure affect gas exchange?
Gases move from high to low partial pressure (O₂ into blood, CO₂ out).
Why is CO₂ more soluble in blood than O₂?
CO₂ has higher solubility, making it easier to dissolve and transport.
How does oxygen move in external respiration?
From alveoli (high O₂) to capillaries (low O₂).
How does CO₂ move in external respiration?
From capillaries (high CO₂) to alveoli (low CO₂) for exhalation.
How does oxygen move in internal respiration?
From capillaries (high O₂) to body tissues (low O₂).
How does CO₂ move in internal respiration?
From tissues (high CO₂) to capillaries (low CO₂) for transport to the lungs.
