Sheet Heart Dissection Lab
Safety and Respect
1. The tray is the boundary
a) No tissue parts should be outside of the tray, for any reason, at any time.
2. Preserving fluid should not be splashed or spilled if possible.
3. Wash hands thoroughly before and after handling materials. Use non-latex gloves.
4. Respect
a) The heart is a complex, complicated, and entirely awesome organ. It deserves respect for what it can teach us.
Please be respectful of this resource.
5. Safety
a) Scalpels are made for cutting flesh. Be careful. Do not have the scalpel in your hand while reaching for
anything else.
b) Use probes for examining the tissue – not the scalpel. Scalpels are for cutting only.
6. Cleanup
a) Return heart to labeled baggie for your group
b) Trays: rinse off and pat down with paper towel
c) Lab tools (probe, scalpel, etc.): rinse off and place back on tray
d) Place tray on back counter and throw away any used paper towels
e) Place baggie with heart in designated area for your class period
Review of structures
Review the diagram and label the main parts of the heart
4 chambers (left and right atrium, left and right ventricle)
4 major vessels (aorta, vena cava, pulmonary vein and artery)
4 valves (tricuspid, pulmonary, mitral, aortic)
Observation: External Anatomy
Most heart diagrams show the left atrium and ventricle on the right side of the diagram. Imagine the heart in the
body of a person facing you. The left side of their heart is on their left, but since you are facing them, it is on
your right.
Identify the right and left sides of the heart. Look closely and on one side you will see a diagonal line of blood
vessels that divide the heart. The half that includes all of the apex (pointed end) of the
heart is the left side. Confirm this by squeezing each half of the heart. The left half will feel much firmer and
more muscular than the right side. (The left side of the heart is stronger because it has to pump blood to the
whole body. The right side only pumps blood to the lungs.)
Place a plain gray pin on the apex of the heart.
What are the coronary blood vessels?_________________________
________________________________________________________
Identify and sketch the anterior and posterior views
Anterior (front)
Posterior (back)
What is the major distinguishing feature that tells you it’s the anterior view?
What is the major distinguishing feature that tells you it’s the posterior view?
Identify the base of the heart (top with major vessels). Examine the flaps of darker tissue on the top of the heart.
These ear-like flaps are called auricles. Find the large opening at the top of the heart next to the right auricle.
This is the opening to the superior vena cava, which brings blood from the top half of the body to the right
atrium (the atria are the top chambers in the heart). Stick a probe down this vessel. You should feel it open
into the right atrium. A little down and to the left of the superior vena cava there is another blood vessel
opening. Insert your probe into this; it should also lead into the right atrium. This is the inferior vena cava,
which brings blood from the lower tissues. You can also see another blood vessel next to the left auricle. This is
a pulmonary vein that brings blood from the lungs into the left atrium.
Sticking straight up from the center of the heart is the largest blood vessel you will see. This is the aorta, which
takes oxygenated blood from the left ventricle to the rest of the body (the ventricles are the lower chambers of
the heart). The aorta branches into more than one artery right after it leaves the heart, so it may have more than
one opening on your heart specimen. Look carefully at the openings and you should be able to see that they are
connected to each other.
Behind and to the left of the aorta there is another large vessel. This is the pulmonary artery
which takes blood from the right ventricle to the lungs.
Place the following pins on the major
vessels of the heart:
Dark blue (2): auricles
Light blue/turquoise (2): Superior and
Inferior Vena Cava
Purple: Pulmonary vein
Yellow: Pulmonary Artery
Pale Green: Aorta
Call Mrs. Crow or another teacher to
confirm the placing of the pins.
Observation: Internal Anatomy
Identify the two halves as either anterior or posterior. How can you tell? ___________________________
__________________________________________________________________________________________
Identify the right and left sides of the heart. How can you tell? ____________________________________
__________________________________________________________________________________________
Locate the four chambers of the heart, the left and right atriums, and the left and right ventricles. Place
pins in each of them.
Locate and place a pin in the septum. What is the septum’s purpose? ______________________________
_________________________________________________________________________________________
Sketch the inside of the heart and label the chambers and the septum.
Internal Anatomy
Take a ruler and measure in centimeters the width of the ventricle walls.
Width of left ventricle wall: _____________ cm
Width of right ventricle wall: ____________ cm
Width of septum: ___________ cm
Locate the tricuspid valve. What is its purpose? _______________________________________________
________________________________________________________________________________________
Locate the mitral valve. What is its purpose? _________________________________________________
________________________________________________________________________________________
Locate the chordae tendineae. What is its purpose? ____________________________________________
________________________________________________________________________________________
Locate the papillary muscles. What is its purpose? _____________________________________________
_________________________________________________________________________________________
Using the probe, trace the flow of blood through the main blood vessels and chambers of the heart.
1. Start with the vena cava.
2. From the vena cava into the right atrium
3. Through the tricuspid valve into the right ventricle
4. From the right ventricle into the pulmonary artery
5. From the artery, into the lungs, and back through the pulmonary veins
6. From the veins into the left atrium
7. From the left atrium, through the mitral valve, into the left ventricle
8. From the ventricle, into the aorta and to the body
Trace these steps many times with you group. I will ask each group to demonstrate this pathway.