Download Figure 1 Figure 2 Introduction: Before beginning this activity, let`s

Figure 1
Figure 2
Introduction:
Before beginning this activity, let’s become familiar with terms of oxygenated and
deoxygenated. All blood vessels bringing blood to the heart’s right side and
leaving from the right ventricle contain blood that is deoxygenated. Deoxygenated
blood is blood that is low in oxygen and high in carbon dioxide.
All blood vessels bringing blood to the heart’s left side and leaving from the left
ventricle contain oxygenated blood. Oxygenated blood is blood that is high in
oxygen and low in carbon dioxide.
You can get a good look at the inside parts of the heart by dissecting one. A sheep
heart is a good subject because it is similar in size and shape to the human model.
Purpose:
In this investigation you will:
 Observe the outside and inside of a sheep’s heart
 Locate, draw, and label heart parts

Materials:
 Sheep Heart
 Dissecting pan
 Probes
Procedure:
Part 1:
1. Place the heart in the dissecting pan so that it looks like the heart in figure 1.
(The right side of the heart is on your left side. The left side of the heart is on
your right.)
2. Draw the front of the heart and label the Right Ventricle, Left Ventricle,
Right Atrium, Left Atrium, Pulmonary Artery, Pulmonary Veins, and
Aorta (Use Fig.2 to help you label)
Draw and label the outside of the sheep heart here.
Part 2:
1. Insert your dissecting scissors into the superior vena cava and make an
incision down through the wall of the right atrium and ventricle, as
shown by the dotted line in the external heart picture. Pull the two sides
apart and look for three flaps of membrane. These membranes form the
tricuspid valve between the right atrium and the right ventricle. The
membranes are connected to flaps of muscle called the papillary muscles
by tendons called the chordae tendinae or "heartstrings." This valve
allows blood to
enter the ventricle
from the atrium,
but prevents
backflow from the
ventricle into the
atrium
Figure 3
3. The largest chamber is the _______________________
4. Examine the thickness of the muscle that makes up the sides of the heart
ventricles. Examine the walls of the aorta for thickness too.
5. Which chamber, the atrium or ventricle has thicker walls?
_____________________________
6. Draw the inside of the heart. (Pick one side to draw). Use
the Figure 4 to help you.
7. Label the Right Atrium, Left Atrium, Right Ventricle, Left
Ventricle, Aorta, Pulmonary Artery and Pulmonary Vein
Figure 4