Gas exchange and internal transport
Diffusion across exchange surfaces and bulk transport serve different roles.
Key knowledge
Animal gas exchange relies on diffusion across surfaces, with surface area and diffusion distance constraining exchange. Many larger animals combine specialized respiratory surfaces with internal bulk transport. Circulatory systems distribute materials, while respiratory arrangements vary substantially among animal groups.
Conditions and scope
- Some animals use direct diffusion or tracheal systems; circulation is not the oxygen-delivery route in every animal.
- Exchange depends on geometry, diffusion gradients and tissue demands.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Mary Ann Clark, Matthew Douglas and Jung Choi — OpenStax, Rice University2 sources
Evidence and review
Source gas-exchange surfaces and open/closed circulation comparisons.
2026-10-10 · Checked diffusion/bulk-flow distinction and organismal variation.
Entry details
Permanent link to this entry ↗- Record identity
- bio-gas-exchange-circulation
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- university-reference.1
- Structured reference record
- University reference