Unit 03 · The Cardiovascular System
This unit follows the blood: the four heart chambers and the valves that keep it moving one way, the cardiac cycle you can hear as “lub-dub,” the split between the pulmonary and systemic circuits, the arteries, veins, and capillaries that carry it, and what blood pressure and pulse actually measure. Mastery means you can take a blood-pressure and pulse reading, interpret it, and trace a drop of blood through the whole loop — not just label a diagram.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Heart chambers & valves | Cannot name the four chambers or the valves between them. | Names the four chambers but cannot say which valve guards each or which side pumps where. | Names the four chambers and the valves on a model or specimen, and explains which side pumps to the lungs and which to the body. |
| The cardiac cycle & heart sounds | Cannot describe what happens in a single heartbeat. | Describes the heart filling and emptying but cannot link the “lub-dub” to the valves closing. | Walks through the cardiac cycle — fill, contract, eject — and ties the two heart sounds to the valves snapping shut. |
| Systemic & pulmonary circulation & blood vessels | Cannot tell the two circuits apart or name the three vessel types. | Names arteries, veins, and capillaries but cannot trace blood through the pulmonary and systemic loops. | Distinguishes arteries, veins, and capillaries by structure and traces a drop of blood through both the pulmonary and systemic circuits. |
| Blood pressure, pulse & blood composition | Cannot say what blood pressure or pulse measures, or what blood is made of. | Reads a pulse or a blood-pressure number but cannot explain what systolic and diastolic mean, or lists blood parts without their jobs. | Explains what pulse and the two blood-pressure numbers measure and names the parts of blood with what each one does. |
| Lab technique (BP, pulse & heart sounds) | Cannot take a pulse or place the stethoscope and cuff correctly. | Takes a pulse or a blood-pressure reading but cannot interpret the result or hear the heart sounds. | Measures pulse, blood pressure, and heart sounds with correct technique and interprets the readings against normal ranges. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“I heard the ‘lub’ when the valves between the atria and ventricles snapped shut as the ventricles squeezed, then the ‘dub’ when the valves out to the arteries closed. The pulse at the wrist is that same contraction pushing a pressure wave down the artery — I counted 72 in a minute.”
“The heart goes lub-dub. Blood pressure is… a number? I felt something at the wrist but I don’t know what it was.”
You demonstrate this unit by measuring pulse, blood pressure, and heart sounds and interpreting them aloud — and by tracing a drop of blood through the heart and both circuits — not a multiple-choice test. A criterion counts as mastered only when you can both take the reading at the bench and explain the anatomy behind it. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.