KEY of HeartDissectionlab 2020-2021 - Sheep Heart Dissection Lab ... - Free Printable

Let’s go step by step to answer each question based on the heart diagram and standard anatomy knowledge.

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1. What are the four chambers of the heart in the correct order?

The heart has four chambers: two on top (atria) and two on bottom (ventricles). Blood flows in this order:

→ Right Atrium → Right Ventricle → Left Atrium → Left Ventricle

But note: blood doesn’t flow directly from right ventricle to left atrium — it goes through the lungs first. But if we’re listing the chambers in the order blood passes through them during one full circuit, it’s:

Right Atrium → Right Ventricle → (lungs) → Left Atrium → Left Ventricle

However, since the question says “in the correct order” without specifying circulation path, most textbooks list them as:

Right Atrium, Right Ventricle, Left Atrium, Left Ventricle

*(This is the typical anatomical listing order — upper right, lower right, upper left, lower left)*

✔ Final Answer for #1:
Right Atrium, Right Ventricle, Left Atrium, Left Ventricle

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2. How many chambers are located in the mammalian heart? List these chambers.

Mammals (including humans) have a four-chambered heart.

Chambers:
- Right Atrium
- Right Ventricle
- Left Atrium
- Left Ventricle

✔ Final Answer for #2:
Four chambers: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle

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3. Which structures are the pumping chambers of the heart?

The ventricles do the heavy pumping.

- Right Ventricle pumps blood to the lungs.
- Left Ventricle pumps blood to the whole body.

Atria just receive blood and push it down into ventricles — they don’t pump far.

✔ Final Answer for #3:
Right Ventricle and Left Ventricle

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4. Which structures are the receiving chambers of the heart?

The atria receive blood coming into the heart.

- Right Atrium receives deoxygenated blood from the body.
- Left Atrium receives oxygenated blood from the lungs.

✔ Final Answer for #4:
Right Atrium and Left Atrium

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5. Describe the role of the tricuspid valve when you consider the route that right ventricle takes after the right atrium contracts to move the blood to the pulmonary artery.

Let’s trace the path:

1. Right atrium contracts → pushes blood into right ventricle.
2. Between right atrium and right ventricle is the tricuspid valve.
3. When right atrium contracts, tricuspid valve OPENS to let blood flow into right ventricle.
4. Then, when right ventricle contracts, tricuspid valve CLOSES tightly so blood doesn’t flow back into the atrium.
5. Instead, blood is forced out through the pulmonary valve into the pulmonary artery → to the lungs.

So the tricuspid valve acts like a one-way door: opens to let blood in from atrium to ventricle, then slams shut when ventricle pumps to prevent backup.

✔ Final Answer for #5:
The tricuspid valve opens to allow blood to flow from the right atrium into the right ventricle. When the right ventricle contracts, the tricuspid valve closes to prevent blood from flowing back into the right atrium, ensuring blood moves forward into the pulmonary artery toward the lungs.

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Final Answer:
1. Right Atrium, Right Ventricle, Left Atrium, Left Ventricle
2. Four chambers: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle
3. Right Ventricle and Left Ventricle
4. Right Atrium and Left Atrium
5. The tricuspid valve opens to allow blood to flow from the right atrium into the right ventricle. When the right ventricle contracts, the tricuspid valve closes to prevent blood from flowing back into the right atrium, ensuring blood moves forward into the pulmonary artery toward the lungs.