Circulatory System Worksheet | PDF - Free Printable

This is a worksheet on the human circulatory system that asks you to color-code the heart diagram based on whether the structures contain deoxygenated or oxygenated blood.

Let me break down the solution step by step.

Step 1: Understand the Task

The instructions are:
- b. Color structures containing deoxygenated blood blue.
- c. Color structures containing oxygenated blood red.

I need to identify which parts of the heart and associated vessels carry which type of blood.

Step 2: Analyze the Heart's Blood Flow

The human heart has four chambers and two main circuits: pulmonary (lungs) and systemic (body).

- Deoxygenated Blood Pathway (Blue):
- Enters the heart via the Superior Vena Cava and Inferior Vena Cava.
- Flows into the Right Atrium.
- Then into the Right Ventricle.
- Is pumped out through the Pulmonary Artery to the lungs for oxygenation.

- Oxygenated Blood Pathway (Red):
- Returns from the lungs via the Pulmonary Veins.
- Enters the Left Atrium.
- Then flows into the Left Ventricle.
- Is pumped out through the Aorta to the rest of the body.

Step 3: Apply the Coloring Rules to Each Labeled Structure

Based on the above, here is how each structure should be colored:

- Superior Vena Cava: Carries deoxygenated blood → Blue
- Inferior Vena Cava: Carries deoxygenated blood → Blue
- Right Atrium: Receives deoxygenated blood → Blue
- Right Ventricle: Pumps deoxygenated blood → Blue
- Pulmonary Artery: Carries deoxygenated blood to lungs → Blue
- Pulmonary Vein: Carries oxygenated blood from lungs → Red
- Left Atrium: Receives oxygenated blood → Red
- Left Ventricle: Pumps oxygenated blood → Red
- Aorta: Carries oxygenated blood to body → Red

Step 4: Address the Valves

The valves (Tricuspid, Pulmonary, Mitral, Aortic) are not vessels themselves but control the flow between chambers and out of the heart. They should be colored based on the blood they are in contact with *at the point of flow*.

- Tricuspid Valve: Between Right Atrium and Right Ventricle → Both sides have deoxygenated blood → Blue
- Pulmonary Valve: Between Right Ventricle and Pulmonary Artery → Both sides have deoxygenated blood → Blue
- Mitral (Bicuspid) Valve: Between Left Atrium and Left Ventricle → Both sides have oxygenated blood → Red
- Aortic Valve: Between Left Ventricle and Aorta → Both sides have oxygenated blood → Red

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Final Solution Summary

To complete the worksheet, you would color the diagram as follows:

- Color BLUE (deoxygenated blood):
- Superior Vena Cava
- Inferior Vena Cava
- Right Atrium
- Right Ventricle
- Pulmonary Artery
- Tricuspid Valve
- Pulmonary Valve

- Color RED (oxygenated blood):
- Pulmonary Vein
- Left Atrium
- Left Ventricle
- Aorta
- Mitral Valve
- Aortic Valve

This coloring accurately reflects the path of blood flow through the heart, separating the deoxygenated (blue) circuit from the oxygenated (red) circuit.