Download Heart dissection

Name ___________________________________________________ Date _______________________________
Biology 9
Heart Dissection Lab
Introduction
We will be dissecting hearts from adult pigs, whose circulatory systems are basically identical to those of humans. These
hearts are fresh from the butcher, so they are raw and not preserved. While the blood has been drained from them,
they will still be somewhat bloody, drippy, and messy.
Some important things to keep in mind:
I. Respect. Remember that this heart once belonged to a living animal. Treat it respectfully and try to learn as
much as you can in order to honor its life and death.
II. Safety. Since you will be working with raw meat, it is important not to touch your face with your messy
hands. You will wear aprons and gloves, and should wash your hands thoroughly with soap and water
afterwards.
III. More Safety. You will be working with scalpels, which are sharp. Never cut towards yourself, towards your
fingers, or towards another person with the scalpel.
IV. Patience. Dissections are always mushy and confusing. The pictures always make it look really nice and neat
inside, but when you open it up, it’s one big goopy mess and it’s always hard to figure anything out. Don’t panic
if it doesn’t look familiar at first. Be patient, poke around, look at the picture, and try to figure out what you
can. It’s okay if you can’t find everything; you’re looking at a real organ, not a diagram, and not everything is
going to be exactly where it’s “supposed” to be.
Pre-Lab: Before you begin the dissection, answer these pre-lab questions to review what you’re about to see.
1. Review the diagram of the heart, below. Then, for each structure, write a brief explanation of where it sends
blood and whether the blood it carries is oxygen-rich or oxygen-poor. Some examples are shown. You may
need to check your textbook (see Figure 37-2 on p. 944) for help.
Vena cava (superior and inferior) – Bring O2-poor
blood from the body to the right side of the heart.
Right side of the heart (atrium & ventricle) –
Pulmonary artery –
Pulmonary vein – Brings O2-rich blood from the
lungs to the left side of the heart.
Left side of the heart (atrium & ventricle) –
Aorta –
2. What is the difference between…
a) an atrium and a ventricle?
b) the left side and the right side of the heart?
c) an artery and a vein?
3. Which chambers of the heart do you think will have more/thicker muscle, the atria or the ventricles? Why?
4. Which side of the heart do you think will have more/thicker muscle, the left or the right side? Why?
5. Which artery do you expect to have thicker walls – the aorta or the pulmonary artery? Both carry blood
away from the heart, but one has to withstand stronger pumping than the other. Which one? Why?
6. A coronary artery is one that supplies the muscles of the heart itself with blood.
a. Why does the heart muscle need to receive blood flow? Make your answer nice and specific.
b. What do you think would happen if coronary arteries got clogged or blocked? Why?
7. The heart contains a number of different valves. Use your textbook (pages 944-945) to answer these
questions…
a. What is the function of valves in the heart?
b. Where are some of the valves located?
Procedure & Observations/Results
1. Assign roles to your team members. Each person must have an assigned role (if your group has 5 people, then 2
people can share one role). Keep in mind that everyone may have a turn touching/cutting the heart if they want.
Procedure Manager – This person reads each step aloud and checks it off when it has been completed. This
person should also record all answers and drawings in the packet as you go.
Person filling this role: __________________________________
Results Manager – This person makes sure everyone in the group discusses the answers to each question and
understands, and then records them in the lab packet. This person also draws sketches when needed.
Person filling this role: __________________________________
Materials Manager – This person is responsible for getting the dissecting materials for the group, keeping
track of them during the dissection, and cleaning them up when the dissection is over. This person will also help
with the actual dissection.
Person filling this role: __________________________________
Heart Manager – This person will lead the actual dissection, though she/he must let others help when they
want to. This person must be willing to get his/her hands into the heart!
Person filling this role: __________________________________
2. Everyone must get an apron, gloves, and goggles, then send the materials manager to get your dissecting
materials.
3. OBSERVATION INSTRUCTIONS: The Procedure Manager is to read and check off each step as your
group completes it.

Examine the heart carefully – pay attention to what it looks like and how it feels. Find both atria
and both ventricles - the atria are sort of like hollow flaps above the larger ventricles.

Look at the fat tissue (which in many cases marks the separation of chambers and the location of
the coronary arteries). Can you see the fat and the coronary arteries?

Also look for holes and vessels leading into and out of the heart.

Now, you must orient yourself to the heart – which side is the front? This is easiest to do by
locating the pulmonary artery and the aorta, and figuring out which is which. They are the light-pink
large vessels protruding from the top of the heart. If your pre-lab prediction was correct, you know
that the aorta should have thicker walls. Observe, and feel the walls of each vessel. Stick your
fingers down them – the pulmonary artery should lead into the right ventricle, while the aorta
should cross behind and lead into the left ventricle.

Once you have established this, lay your heart down so that its front is facing up and the right side is
on your left (the way that heart diagrams are usually shown).

Draw what you see in the space below. Label the left and right atria and ventricles, the pulmonary
artery, and the aorta. Then, write some descriptions: colors, textures, shapes, etc.. Note
anything interesting or surprising.
4. DISSECTION INSTRUCTIONS:

Find the holes in the right atrium (this is where blood would enter), and look inside. Try to see the
valve between the right atrium and the right ventricle. (It’s kind of hard to see, but it’s the stringy
tissue between the right atrium and the right ventricle.)

Describe what you see:

Does blood entering the right atrium carry oxygen-rich or oxygen-poor blood?

Insert your scissors into the holes in the right atrium, and cut down through the right atrium,
through the valve between the right atrium and the right ventricle and into the right ventricle.

Open up the walls of both chambers. Notice the amazing network of coronary arteries!

Describe or draw what you see:

How are the right atrium and ventricle different?

The pulmonary artery is the artery that leaves the right ventricle to go to the lungs. Feel in the right
ventricle and find the pulmonary artery.

Where would the pulmonary artery carry blood?

Does it carry oxygen-rich or oxygen-poor blood?

Cut open the pulmonary artery just a little bit from the top until you can see the valve between the
pulmonary vein and the left atrium (if you can – sometimes this is hard).

Now you will move on to the left side of the heart.

When the blood leaves the right ventricle through the pulmonary artery, it goes to the lungs, and
then comes back through the pulmonary vein. The pulmonary vein is the vein that enters the left
atrium, but it is not included in your heart. Find the left atrium, and try to see where the pulmonary
veins would enter.

Where is the pulmonary vein coming from?

Does the pulmonary vein carry oxygen-rich or oxygen-poor blood?

Cut through the walls of the left atrium, noticing the valve between it and the left ventricle.

Continue the cut down through the left atrium, through the valve between the left atrium and the
left ventricle and into the left ventricle.

What is the function of the left ventricle? Does it contain oxygen-rich or oxygen-poor blood, and
where does it pump blood?

Is the left ventricle thicker or thinner than the right ventricle? Why do you think this is?

The aorta is the big artery with the thickest walls. Stick your finger down the aorta into the
chamber that it leaves from.

Where is the aorta coming from? Where does it go (where does it transport blood)?

Does it carry oxygen-rich or oxygen-poor blood?

Cut open the aorta. Describe how its walls compare to those of the pulmonary artery.
Final Reflection (Complete on the reverse of this page)
Write 1-2 paragraphs describing the heart dissection. Include:
 What was it like? Describe the things you saw, felt, etc.
 What was most surprising or unexpected? What was coolest?
 What are two concrete things you learned about the heart from doing this dissection?