Transcript Heart Dissection Walk Through

Heart Dissection Walk Through
“Don’t Break My Heart, My Achy Breaky Heart”
Step 1 – What to Expect When you
First See the Heart
When you first obtain your heart, you will see
 a lot of white fatty tissue surrounding it. It is usually a waste of time to
try to remove this tissue.
 a lot of tiny blood vessels on the outside of the heart (these feed the
tissue of the heart – remember the heart itself needs oxygen too!)
 a shape you may not expect – often the packaging and preserving
process can cause this
How will you know which side is front, back, right, left?
 The front side of the heart curves; the backside is flatter.
 The front has a couple of key features:
1) a large pulmonary artery that extends off the top
2) the flaps of the auricles covering the top of the both of the
2 atria (upper chambers)
Front Side of Heart
Back Side of Heart
Remember that if you are looking at the back
of the heart, then the right and left sides
are the same as your right and left hand.
Step 2 - Supplies You Will Be Given
BEFORE - Prepare the Area
newspapers
DURING - To Dissect
Probes
Scissors Blades
DURING - To mark specific structures
Pencils
Wool
AFTER - Clean-Up
Paper Towel
Gloves
Lab Questions (pre-read them so you are prepared)
Step 3 – Locate the 4 Main Vessels
(2 arteries, 2 veins)
 Use your fingers to probe around the top of the heart. Four
major vessels can be found entering the heart:
Two arteries
 Pulmonary artery (from __________)
(aorta is a little behind it)
 Aorta (from _________)
Two veins
 Superior vena cava (from _____________)
 Pulmonary vein (from _______________)
Aorta
Pulmonary Artery
 Aorta *may be covered by fat, so use your fingers to poke
around until you find the opening. Push your finger all
the way in the aorta and you will feel inside of the left
ventricle.
 The left ventricle has a very thick wall, unlike the right ventricle.
Why do you think this is so? _________________________
Insert your finger through the pulmonary vessel to feel the left
ventricle and you will notice and feel that it is much thinner than the
left side of the heart.
 With your fingers or probes in the aorta and the pulmonary artery
you should notice that they criss-cross each other, with the
pulmonary artery in the front.
Step 3 – 2 Major Veins
The two major veins that enter the heart
can be found on the backside because
both enter the atria.
On the left side, you should be able to find
the opening of the pulmonary vein as it
enters the left atrium.
The superior vena cava enters the right
atrium.
In many preserved hearts, the heart was cut
at these points, so you won't see the
vessels themselves, you will just find the
openings. Again, use your fingers to feel
around the heart to find the openings.
Pulmonary
Artery
Pulmonary
Vein
Aorta
Superior Vema
Cava
Step 5 – Make the Incision
Now that you have all of the vessels located and marked, you can
now open the heart to view the inner chambers.
Use the superior vena cava and pulmonary vein as guides for where
to cut.
You are basically going to be cutting each side of the heart so that
you can look inside.
The heart below is marked to show you where the two incisions
should be made.
STEP ONE
STEP TWO
Step 6 – Viewing the 4 Chambers
 At this point it is helpful to have 2 hands
 one hand holds the heart apart so you can take a peek inside
 one hand to use a probe to locate the specific parts
 Your colored pencils you used to mark the heart in step 2 can
also now be used to see where those vessels connect within
the heart.
Example: the aorta pencil can now be seen ending in
the left ventricle.You can also now see how
much thicker the walls of the left ventricle
are compared to the right ventricle.
Step 7 -Other Obvious Structures
*chordae tendinae
These tendons hold the heart valves in place, sometimes they
are called the "heartstrings". When someone is attracted to
someone else we can say “They are pulling on your
heartstrings”
*valves
*were probably cut when the heart was opened, but if you
follow the "cords" they should lead you to a thin flap of skin
that opens and closes to let blood in/out of the heart
*atrioventricular (bicuspid) valve (left side)
*tricuspid valve (right side)
Step 8– Trace the Path of the Blood
 Using wool trace the path of blood from the
right atrium to the left ventricle.
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Superior Vena Cava (vein from body)
Right atrium
Left atrium
Pulmonary Artery
Pulmonary Veins
Left Atrium
Left Ventricle
Aorta (artery to the body)
DID YOU SUCCEED?
Step 9 – Clean-Up
 Clean up
 Newspaper , paper towel, wool -- garbage.
 Wash and dry scissors, probes, blades, pencils
 Wipe the table area. Rinse. Repeat until there is
no streaking.
 Return the dissection tray to the area indicated.
 Lab Summary sheet to be completed and turned in.
Plux Demo (trachea, heart, lungs)
 Identify the *trachea
*bronchi
*bronchiole tubes (if visible)
*alveoli
• Touch the lungs of the pig and think about how they
feel
 What do you think will happen to the lungs if the
teacher were to blow air into the trachea?