Heart Dissection Lab - Suburban Science - Free Printable

Student Lab Worksheet: Heart Dissection

The worksheet provided focuses on the external and internal anatomy of the heart. Below is a detailed explanation and solution for each part of the worksheet.

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#### External Anatomy
1. Label the apex, right atrium, left atrium, and interventricular groove in the image below.

- Apex: The pointed, lower tip of the heart.
- Right Atrium: The upper chamber on the right side of the heart.
- Left Atrium: The upper chamber on the left side of the heart.
- Interventricular Groove: The groove that separates the left and right ventricles on the surface of the heart.


2. Name and describe the two loops of the mammalian circulatory system.

- Pulmonary Circulation: This loop carries deoxygenated blood from the heart to the lungs (via the pulmonary arteries) and returns oxygenated blood back to the heart (via the pulmonary veins). It involves the right side of the heart.
- Systemic Circulation: This loop carries oxygenated blood from the heart to the body tissues (via the aorta) and returns deoxygenated blood back to the heart (via the superior and inferior vena cava). It involves the left side of the heart.

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#### Internal Anatomy
3. What is the purpose of the tricuspid valve and where is it located?

- Purpose: The tricuspid valve prevents backflow of blood from the right ventricle into the right atrium during ventricular contraction (systole).
- Location: It is located between the right atrium and the right ventricle.

4. What is likely different between the tricuspid valve and the bicuspid valve?

- Number of Leaflets:
- Tricuspid Valve: Has three leaflets (cusps).
- Bicuspid Valve: Has two leaflets (also called the mitral valve).
- Location:
- Tricuspid Valve: Between the right atrium and right ventricle.
- Bicuspid Valve: Between the left atrium and left ventricle.
- Function:
- Both valves prevent backflow of blood, but the bicuspid valve is associated with the higher-pressure left side of the heart, which pumps blood to the entire body, while the tricuspid valve is associated with the lower-pressure right side of the heart, which pumps blood only to the lungs.

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#### Dorsal Side of the Heart
5. Label the following structures on the dorsal side of the heart using the following terms: left ventricle, chordae tendineae, right atrium, right ventricle, left atrium, aorta, tricuspid valve, bicuspid valve, aortic semilunar valve, papillary muscles, interventricular septum, apex.

- Left Ventricle: The thick-walled pumping chamber that sends oxygenated blood to the body via the aorta.
- Chordae Tendineae: Cord-like structures that attach the valve cusps to the papillary muscles, preventing the valves from being pushed backward into the atria during ventricular contraction.
- Right Atrium: Receives deoxygenated blood from the body via the superior and inferior vena cava.
- Right Ventricle: Pumps deoxygenated blood to the lungs via the pulmonary arteries.
- Left Atrium: Receives oxygenated blood from the lungs via the pulmonary veins.
- Aorta: The major artery that carries oxygenated blood from the left ventricle to the body.
- Tricuspid Valve: Located between the right atrium and right ventricle, preventing backflow of blood.
- Bicuspid Valve: Located between the left atrium and left ventricle, preventing backflow of blood.
- Aortic Semilunar Valve: Prevents backflow of blood from the aorta into the left ventricle.
- Papillary Muscles: Muscles within the ventricles that anchor the chordae tendineae to the valve cusps.
- Interventricular Septum: The muscular wall that separates the left and right ventricles.
- Apex: The pointed, lower tip of the heart.


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#### Flow of Blood Through the Heart
6. Follow the flow of blood through the heart.

- Body tissues → superior & inferior vena cava → right atrium → right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → aorta → body tissues

- Explanation:
1. Deoxygenated blood from the body enters the right atrium via the superior and inferior vena cava.
2. Blood flows from the right atrium into the right ventricle.
3. The right ventricle pumps blood into the pulmonary arteries, which carry it to the lungs for gas exchange.
4. Oxygenated blood returns to the heart via the pulmonary veins, entering the left atrium.
5. Blood flows from the left atrium into the left ventricle.
6. The left ventricle pumps oxygenated blood into the aorta, which distributes it to the body tissues.

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Summary of Solutions

1. External Labels: Apex, right atrium, left atrium, interventricular groove.
2. Circulatory Loops: Pulmonary circulation (right side) and systemic circulation (left side).
3. Tricuspid Valve: Prevents backflow from the right ventricle to the right atrium; located between them.
4. Valve Differences: Tricuspid valve has three leaflets, while the bicuspid valve has two; they are located on opposite sides of the heart.
5. Dorsal Labels: Left ventricle, chordae tendineae, right atrium, right ventricle, left atrium, aorta, tricuspid valve, bicuspid valve, aortic semilunar valve, papillary muscles, interventricular septum, apex.
6. Blood Flow: Body tissues → vena cava → right atrium → right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → aorta → body tissues.

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This completes the worksheet. If you have any further questions or need additional clarification, feel free to ask!