Resp 1 Flashcards
What is the primary purpose of respiration in animals?
To supply ATP for cellular functions by consuming O₂ and producing CO₂ via mitochondrial respiration.
What are the two types of respiration in animals?
- External respiration – gas exchange between the environment and cells.
- Internal respiration – cellular use of O₂ to produce ATP (e.g., cellular respiration).
What is the oxygen transport pathway (O₂ cascade)?
A series of steps moving oxygen from the environment to mitochondria, and CO₂ in the reverse direction.
What are the 4 steps of external respiration?
- Ventilation
- Diffusion at respiratory surface
- Circulatory transport
- Diffusion into tissues
Why is external respiration more limiting in larger animals?
Because diffusion alone isn’t sufficient due to increased diffusion distance and decreased SA:V ratio.
How do small animals like marine worms perform gas exchange?
Through simple diffusion across their body surface.
What adaptations help large animals meet oxygen demands?
Specialized structures like gills and lungs, and ventilation mechanisms for bulk flow.
What are the physical challenges of respiration in water?
Low O₂ availability, low diffusion rate, and low solubility of O₂.
How do fish maximize oxygen extraction in water?
Using countercurrent exchange in gills: water flows opposite to blood, maintaining a constant O₂ gradient.
What happens if fish used concurrent flow instead of countercurrent?
The diffusion gradient would diminish quickly, reducing oxygen uptake efficiency.
How do insects perform gas exchange?
Through a tracheal system of air-filled tubes ending in fine tracheoles, bringing O₂ directly to tissues.
What are spiracles in insects?
Openings that regulate air intake, water loss, and dust exclusion.
How do birds ventilate their lungs?
With rigid lungs and expandable air sacs, requiring two cycles of inhalation/exhalation.
What is the key feature of gas exchange in birds?
Crosscurrent flow – air flows through parabronchi perpendicular to blood flow for efficient gas exchange.
What role does surface area to volume ratio (SA:V) play in respiration?
High SA:V: simple diffusion is effective. Low SA:V: needs specialized respiratory surfaces to compensate.
