1. Sheep Heart Dissection

2. SAFETY REMINDERS:
*Scalpels are very sharp—always cut AWAY from yourself, with no fingers in the way
*Putting on/taking off scalpels is just as dangerous—ask for help if you’re unsure!
*When you have gloves on, don’t touch anything you can’t wash---if you touch your pencil and get formalin on it, then put that same pencil in your mouth tomorrow….

3. How are the parietal and visceral pericardial layers different?
Gather your dissection equipment and a sheep heart.
Rinse the sheep heart thoroughly with cold water to remove excess preservatives and to flush out blood clots.
If the pericardial sac is intact, then remove the outer layer from its attachment points.
Carefully pull the visceral pericardium (epicardium) away from the myocardium.
How are the parietal and visceral pericardial layers different?

4. Examine the external surface of the heart
Examine the external surface of the heart. Notice the accumulation of ADIPOSE tissue.
This adipose usually accumulates along the boundaries of the heart chambers and along the coronary arteries. Remove as much adipose as possible.
Now you should be able to identify the APEX (bottom left "point" of the heart) and the AURICLES (earlike flaps projecting from the atria).
Carefully scrape away a little adipose tissue so you can see the coronary arteries.

6. Interventricular septum
Anterior view
Pulmonary trunk
Right auricle
Right atrium
Left auricle
Left atrium
Right ventricle
Interventricular septum
Left ventricle

7. Superior view
Superior vena cava
Aorta
Pulmonary trunk
Pulmonary vein

8. Pumps blood to the entire body, through the systemic circuit
5. Squeeze each ventricle.
Which is thicker?
That’s the LEFT VENTRICLE—Why’s it thicker than the right?
Pumps blood to the entire body, through the systemic circuit
The right ventricle pumps only to the lungs through the pulmonary circuit.

9. Locate the PULMONARY TRUNK & AORTA on the superior aspect of the heart.
The pulmonary trunk divides into the left and right pulmonary arteries.
The aorta will be thicker walled and be just behind the pulmonary trunk.
Clear the adipose away from these arteries.

10. LIGAMENTUM ARTERIOSUM
(bypasses the lungs in fetus, ductus arteriosus, pulmonary trunk and aorta connection)

11. PULMONARY SEMILUNAR VALVE
Pulmonary trunk—cut through anterior wall until you see WHICH valve?
Extend the cut through pulm trunk into Rt ventricle
PULMONARY SEMILUNAR VALVE

12. (RIGHT ATRIOVENTRICULAR VALVE)
SCISSORS CUT down/around/up through AV valve—cut alongside the probe to see internal right atrium and WHICH valve?
Probe into the superior vena cava
through right atrium out the inferior vena cava
TRICUSPID
(RIGHT ATRIOVENTRICULAR VALVE)

13. Frontal section Pulmonary trunk via pulmonary SL valve
Pulmonary veins into left atrium
Right atrium
Tricuspid AV valve (chordae tendinae, muscles
Bicuspid AV valve w/chordae tendinae, papillary muscles
Right ventricle w/thinner myocardium
Aortic SL valve, out aorta
Interventricular septum
Left ventricle w/thicker myocardium

14. 11. Pin back the cut edges of superior vena cava, right atrium, right ventricle

15. Right ventricle—papillary muscles, chordae tendineae, tricuspid valve

16. Dispose of solid matter in biohazard bag
Wash ALL PINS, TRAYS, INSTRUMENTS, return to proper place.
Gloves—dispose of in biohazard bag.
WASH HANDS…

17. Sheep heart website