Presentation on theme: "Sheep Heart Dissection. SAFETY REMINDERS : *Scalpels are very sharp—always cut AWAY from yourself, with no fingers in the way *Putting on/taking off scalpels."— Presentation transcript:
Sheep Heart Dissection
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….
1.Gather your dissection equipment and a sheep heart. 2.Rinse the sheep heart thoroughly with cold water to remove excess preservatives and to flush out blood clots. 3.If the pericardial sac is intact, then remove the outer layer from its attachment points. 4.Carefully pull the visceral pericardium (epicardium) away from the myocardium. How are the parietal and visceral pericardial layers different?
5.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. APEX AURICLES 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.
Right ventricle Right atrium Left ventricle Left atrium Left auricle Right auricle Pulmonary trunk Interventricular septum Anterior view
Superior view Pulmonary trunk Aorta Pulmonary vein Superior vena cava
5. 5. Squeeze each ventricle. Which is thicker? LEFT VENTRICLE— 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.
PULMONARY TRUNK & AORTA 6.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.
LIGAMENTUM ARTERIOSUM (bypasses the lungs in fetus, ductus arteriosus, pulmonary trunk and aorta connection)
10.Pulmonary trunk 10.Pulmonary trunk—cut through anterior wall until you see WHICH valve? Extend the cut through pulm trunk into Rt ventricle PULMONARY SEMILUNAR VALVE
SCISSORS CUT down/around/up through AV valve—cut alongside the probe to see internal right atrium and WHICH valve? superior vena cava 9.Probe into the superior vena cava through right atrium out the inferior vena cava through right atrium out the inferior vena cava TRICUSPID (RIGHT ATRIOVENTRICULAR VALVE)
Frontal section Right ventricle w/thinner myocardium Right atrium Left ventricle w/thicker myocardium Bicuspid AV valve w/chordae tendinae, papillary muscles Pulmonary trunk via pulmonary SL valve Interventricular septum Tricuspid AV valve (chordae tendinae, muscles Pulmonary veins into left atrium Aortic SL valve, out aorta
11. Pin back the cut edges of superior vena cava, right atrium, right ventricle