SCIENCE · INVESTIGATE AND EXPLAIN

Reject an oxygen-demand case without inventing a feasible steady state

Integrated oxygen supply links ventilation, diffusion, blood binding, regional mixing, circulation and tissue extraction. A change at one stage need not repair a limitation at another. Delivery is blood flow times arterial oxygen content, while uptake is the portion removed by tissues. Delivery and actual metabolic use are not the same quantity.

Learning outcome: Compare demands20 and30 at flow 4, then flow 6 at demand 30. Retain delivery, permitted uptake, unmet demand and venous content, and state an upstream observation that distinguishes low flow from low content.

Starting recap

Trace cardiovascular and respiratory anatomy, conserve pressure-flow and gas-content ledgers, and distinguish transport, storage, binding and feasible uptake under explicitly supplied nonclinical boundaries.

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Try

At flow 4, delivery is 40 and maximum allowed uptake 24. Requested demand 30 exceeds it by6. The displayed limited uptake 24 leaves venous content 4, and feasibility is rejected. Reporting demand 30 as fully met would contradict the supplied extraction boundary.

Open the experiment

Predict

Does a mathematically positive venous content guarantee that the requested demand is feasible?

Your prediction and reason

Experiment

Compare demands20 and30 at flow 4, then flow 6 at demand 30. Retain delivery, permitted uptake, unmet demand and venous content, and state an upstream observation that distinguishes low flow from low content.

Reject demands beyond a supplied oxygen-extraction boundary

Worked teaching model · synthetic values · Original arterial oxygen content 10, maximum extractable fraction 0.6. Delivery QCa; allowable uptake at most 0.6QCa. If demand exceeds the limit, report unmet demand and boundary uptake, not a fabricated feasible steady state. Fixed coefficients omit feedback and real physiological thresholds.

Flow: 4 volume/time Demand: 30 amount/time

Reset keeps your prediction, captures and practice history.

The requested demand is infeasible under the supplied flow/content/extraction boundary.

Rejecting the demand does not mean physiological need disappears: unmet demand marks failure of a steady supply assumption. Increasing flow or carried content changes delivery, while a constrained extraction fraction can remain limiting. No clinical threshold or safe activity follows.

Conditional quantities; each row retains its own unit
Quantity	Value	Unit
Oxygen delivery	40	amount/time
Maximum allowed uptake	24	amount/time
Requested demand	30	amount/time
Boundary-limited uptake	24	amount/time
Unmet demand	6	amount/time
Venous content under limited uptake	4	amount/volume
Demand feasible under supplied boundary	0	0 no / 1 yes

Original instructional diagrams and parameters, not individual physiological measurements, safety limits or treatment guidance.

The requested demand is infeasible under the supplied flow/content/extraction boundary.

Observation to attach to a capture

Captures preserve recipes and replay their calculated results. They are synthetic model evidence, not physical measurements.

Understand

1. Trace the anatomical pathway

2. Define the mechanism and boundary

The original finite packet fixes arterial content 10 and an imposed maximum extractable fraction 0.6. At flow Q, delivery is 10Q and maximum allowed uptake 6Q. A requested demand D is feasible only when D≤6Q. This is a deliberately stipulated boundary, not a human threshold, exercise limit or claim that extraction always reaches this fraction.

When demand exceeds the boundary, the model reports limited uptake 6Q and unmet demand D−6Q. It does not silently substitute a negative venous content or claim that the tissue’s need disappears. Venous content computed from the limited uptake is 10−uptake/Q; the failure label states that the requested steady demand cannot be supported under these assumptions.

Connecting the upstream models clarifies alternatives. Lower capacity at unchanged saturation can lower arterial content; unequal regional mixing can lower content despite one well-ventilated region; reduced flow can lower delivery despite unchanged content. Distinguishing these requires separate observations. Real compensatory responses, storage and injury are outside the model, so no personal risk or clinical conclusion is justified.

3. Reconstruct the original evidence

4. Predict and investigate

Predict first: Does a mathematically positive venous content guarantee that the requested demand is feasible?

5. Defend a changed transport case

Apply the mechanism to a changed boundary

At flow 6 and demand 30, find delivery, maximum uptake, actual requested uptake, unmet demand and venous content.

Retain the first response, units, uncertainty and any prior feedback exposure in the notebook before comparing this public explanation.

Compare a worked response

Delivery60 and maximum36 admit demand 30. Uptake is 30, unmet demand 0 and venous content 10−30/6=5. This is feasibility only within the fictional boundary, not certification for an actual person.

6. Preserve a bounded explanation

Retain your first prediction, full units and conservation checks, an alternative mechanism and a discriminating observation in the Anatomy course workspace. These invented data are not individual physiological values. Do not perform breath-holding, forced breathing, exercise challenges, blood sampling or personal measurements. Public answer exposure does not establish independent learner or practical competence.

Supporting anatomical mechanism, checked 30 October 2026. Original models, diagrams and exercises; no clinical interpretation or treatment guidance.

Apply

Public practice checks a specific claim. It does not establish independent mastery.

At flow 6 and demand 30, find delivery, maximum uptake, actual requested uptake, unmet demand and venous content.

Your explanation and limitations

Continue

Completion requires a saved prediction, at least one capture and a reflection. Presence checks do not grade your reasoning.

Skipping retains experiments and awards no mastery.

Previous: Infer flow only from a complete oxygen balance Next: Trace digestive transformations without losing atoms

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