Download Lab: Heart Dissection DATE: HOUR

Anatomy & Physiology
NAME: __________________ PARTNER: __________________
Lab: Heart Dissection
DATE: ___________________ HOUR: _________
The hearts that you will be dissecting today is that of a sheep. The sheep heart is similar to human heart in the
appearance and structure, though it is larger.
Objectives:
You will determine:
1.
2.
3.
4.
The mass of the heart
Width at the widest point
Length of the heart from the top to the apex
Thickness of the outer walls of the right and left ventricles
You will identify the major structures listed below:
1.
2.
3.
4.
5.
6.
7.
8.
9.
18.
Right atrium
Left atrium
Right ventricle
Left ventricle
Interventricular septum
Pulmonary artery
Aorta
Coronary vessels
Myocardium
Pulmonary artery semilunar valve
10.
11.
12.
13.
14.
15.
16.
17.
Apex
Doral surface
Ventral surface
Vena cava (superior and inferior)
Pulmonary veins
Mitral (bicuspid) valves
Tricuspid valve
Aortic semilunar valve
Materials:
Apron & goggles
Rubber gloves
Dissection kit
Dissection tray
Disinfectant spray / wipes
Paper towels
Triple beam balance / electronic scale
Metric ruler
Procedure:
(Record your data in the next section)
1. Obtain a heart from your instructor and determine its mass.
Mass of heart: ________________________________ [1]
2. Determine the dorsal and the ventral surfaces of the heart.
3. Determine the width at the widest point.
Width of heart at widest point: ______________________________ [1]
4. Determine the length of the heart at the highest point to the apex.
Length of the heart top superior surface to apex: _____________________________ [1]
5. Locate and observe the coronary vessels. What are their functions? [2]
6. Turn your heart so that the ventral surface is facing up and the dorsal surface is against the bottom of the
dissecting tray. Locate the pulmonary artery and dorsal surface of the aorta. How do your know these are
arteries? (hint: look at the walls of the vessels) [2]
7. Insert your finger into the pulmonary artery. Where does your finger come out inside the heart? [1]
8. Insert your finger into the aorta. Where does your finger come out inside the heart? [1]
9. Locate the atria. How does their size compare to the ventricles? [2]
10. Using your scalpel cut the atria open along the ventral surface.
Thickness of left atrial myocardium: ___________________________________ [1]
Thickness of right atrial myocardium: ____________________________________ [1]
11. Describe the location and appearance of the interventricular septum. [2]
12. Using your scissors and scalpel cut down the outer lateral surface from the atrium down to the ventricles,
around the apex and up the other ventricle to the other atrium. Open the heart like a locket.
Thickness of the left ventricular myocardium at the widest point: __________________________ [1]
Thickness of the right ventricular myocardium at the widest point: __________________________ [1]
13. Why is the left ventricular wall wider than the right ventricular wall? [2]
14. Look inside the chambers and see if you can locate the right and left atrioventricular valves. They will appear as
white, stringy, or thread like structures.
How many flaps make up the right atrioventricular valve? ______________________ [1]
What is the other name for this valve: ___________________ [1]
How many flaps make up the left atrioventricular valve? ________________________ [1]
What is the other name for this valve: ___________________ [1]
15. What direction do the flaps move when they close? Why? [2]
16. Describe the appearance of the interior of the chambers. [4]
17. Again insert your finger in the aorta and the pulmonary artery and observe where your finger comes out. [1]
18. Was there any adipose tissue on the surface of your heart? _____________ [1]
What is the function of this tissue? [1]
19. Describe any irregularities in the heart your dissected. [2]
20. If there were and major irregularities, what was the probable cause? [2]
21. When you complete your dissection exercise, dispose of the heart in the trash cans indicated by your teacher.
Wash your dissecting instruments and dissection tray with soap and water, dry them, and then put them away.
22. Remove your rubber gloves and put them in the same trashcan as above. Wipe your desk area down with Lysol,
and dry it off.
23. Wash your hands thoroughly with soap and water.
Conclusion Questions
1. Which ventricle is thicker and why? [2]
2. What major vessels would have to be cut when removing a heart during a transplant? [4]
3. Where does blood go when it leaves the: [4]
a. left semilunar valve
b. Pulmonary vein
c. Mitral valve
d. Tricuspid valve
4. State whether the blood is oxygenated or deoxygenated when it is in these areas: [4]
a. Entering the lungs
b. Leaving the right side of the heart
c. Aortic semilunar valve
d. Entering the left atrium
5. What is the myocardium? [1]
6. Differentiate between the superior vena cava and the inferior vena cava in terms of where they deliver blood.
[2]
7. How could you recognize the chordae tendonae? [1]
8. Where did you find the coronary arteries? [1]
9. Label the diagram below:
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R