1. Dissection 101: Reasons to Use the Dissection Video and
Accompanying PowerPoint Presentation
Reduce the number of specimens used by a class
Increase the quality of the dissection for the students
Review opportunity, increasing the learning experience for the students
Student unable to dissect due to pregnancy or hypersensitivity to the preservatives
Student chooses not to dissect due to ethical/moral reasons
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2. Dissection 101:
Safety Considerations
Age appropriate activity for the children in your care
Material Safety Data Sheet (MSDS) available for accident reference
Poison control number/phone readily available
Latex free gloves, eye protection and apron/lab coat
Eyewash station, shower and sink
Sharp instruments (cut away from self and others)
Sharps and specimen(s) disposal
Encourage students to report all accidents
Basic science laboratory rules (strictly enforced)
As an educator you are responsible for the implementation of the dissection activity described in the video and PowerPoint. You must have safety procedures and rules established for your classroom and make sure all of the students follow the rules to ensure a safe environment. South Dakota Public Broadcasting and Dakota State University cannot in any way be responsible or liable for any injury as a result of performing the described dissection. Complete the dissection if you feel it is appropriate and safe for your individual class.
Have fun and stay safe!
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3. Dissection 101:
Sheep Heart
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4. Sheep Heart Dissection 101: Getting Started
Use water to rinse the excess preservative from your heart
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5. Sheep Heart Dissection 101: Sheep Heart Click
The sheep heart is an excellent specimen to use for comparative human anatomy in both size and function. The sheep heart is mammalian, having four chambers like the human heart, which includes two atria and two ventricles. The blood flow through the sheep heart is like that of the human heart, in which the blood is pumped from the right side of the heart to the lungs and then from the left side of the heart to the body.
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6. Dissection 101: Sheep Heart Orientation: 1st Example
Anterior view (front)
Posterior view (back)
It is easiest to distinguish the posterior and anterior of the heart by observing
the ventricles. Each heart will
look a little different, but there are specific things to look for. The following slides show three different hearts. (Also, anatomic left and right are from the viewpoint of the specimen. For example, the left ventricle is an anatomical term describing the ventricle on the left side, but it will appear, many times, on the right side when viewed in books, on your tray, and in this PowerPoint.)
Things to
look for:
Right
Ventricle
Right Ventricle
Left
Ventricle
Apex
Anterior view points right; posterior view points left
Posterior interventricular sulcus runs
more vertical
Anterior interventricular sulcus runs
diagonal to the left
The left ventricle has more
resistance when pressed, because the
wall (muscle) is much thicker.
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7. Dissection 101: Sheep Heart Orientation: 2nd Example (different heart)
Anterior view (front)
Posterior view (back)
Things to
look for:
Right
Ventricle
Right Ventricle
Left Ventricles
Apex
Anterior view points right; posterior view points left
Posterior interventricular sulcus runs
more vertical
Anterior interventricular sulcus runs
diagonal to the left
The left ventricle has more
resistance when pressed, because the
wall (muscle) is much thicker.
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8. Dissection 101: Sheep Heart Orientation: 3rd Example (different view)
The connective tissue and fat have been removed from the heart on the left.
Right
Ventricle
Left Ventricles
Right Ventricle
Anterior view (front)
Posterior view (back)
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9. Dissection 101: Sheep Heart Left atrium Structures
Right ventricle – Muscular structure of the heart that pumps oxygen poor blood to the lungs
Right atrium (atria: plural) – Muscular structure of the heart that pumps oxygen poor blood to the right ventricle
Left ventricle – Muscular structure of the heart that pumps oxygen rich blood to the body
Left atrium (atria: plural) – Muscular structure of the heart that pumps oxygen rich blood to the left ventricle
Apex – Inferior pointed region of the heart (left ventricle)
Auricle – Outer ear like region of the left and right atria
Anterior view (front) tilted down
Anterior view (front)
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10. Sheep Heart Dissection 101:
There are many vessels entering and leaving the heart. In general, larger vessels leaving the heart are called arteries and larger vessels carrying blood to the heart are called veins. It can be very difficult to identify the vessels, especially if some have been removed by the supplier. On the following slide we will identify vessels which can be easily identified. Many of the other vessels will be identified later with the use of probes that will follow the flow of blood from the heart.
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11. Sheep Heart Dissection 101: R. A. L. A. R. V. L. V. Click
Easily Identified Vessels
Brachiocephalic artery – Forms right subclavian artery and common carotid artery; oxygen rich
Aorta – Oxygen rich blood from left ventricle to the body
Ligamentum arteriosum – Remnant of ductus arteriosus during fetal development
R. A.
L. A.
Pulmonary Trunk (artery) – Oxygen poor blood from right ventricle to lungs via right and left pulmonary arteries
R. V.
Close-up ligamentum arteriosum
L. V.
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12. Sheep Heart Dissection 101: Getting Started – Initial Cuts
(YouTube Version)
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13. Dissection 101: Sheep Heart Dissection
Use probes to identify the superior and inferior vena cava, which supply oxygen poor blood to the right atrium from the body.
Right atrium
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14. Dissection 101: Sheep Heart Dissection
Use the superior vena cava probe, as a guide, to cut down through the wall of the right atrium and right ventricle
Right atrium
Right ventricle
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15. Dissection 101: Sheep Heart
Right atrioventricular (AV) valve (also called tricuspid valve) – Prevents backflow of blood into right atrium when right ventricle pumps blood to lungs
Right atrium
Right ventricle
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16. Tricuspid valve (right AV valve)
Sheep Heart
Dissection 101:
Tricuspid valve (right AV valve)
Chordae tendineae - Chord like structures (tendon) that connect the tricuspid valve to the papillary muscle
Right atrium
Papillary muscle – Contracts preventing tricuspid valve from entering the atrium when ventricle pumps blood
Right ventricle
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17. Use a probe to locate the pulmonary trunk
Sheep Heart
Dissection 101:
Right ventricle
Use a probe to locate the pulmonary trunk
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18. Dissection 101: Sheep Heart
Once the pulmonary trunk is located, cut the right ventricle along the probe to expose the semilunar valves and pulmonary trunk
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19. Cut right ventricle (probe removed)
Sheep Heart
Dissection 101:
Pulmonary trunk
Pulmonary semilunar valve – Prevents backflow of blood from pulmonary trunk into right ventricle
Close-up view
Cut right ventricle (probe removed)
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20. Dissection 101: Sheep Heart
Left atrium
Left atrium
Use a probe to locate the insertion of the pulmonary veins, which bring oxygen rich blood from the lungs to the left atrium; then cut the left atrium along the probe
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21. Dissection 101: Sheep Heart Left atrium L. V.
Probe is passing through the mitral valve into the left ventricle
Cut along the probe to expose the interior of the left ventricle
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22. Close-up view mitral valve
Sheep Heart
Dissection 101:
Wall left ventricle
Left atrium
Left atrioventricular (AV) valve (also called bicuspid valve or mitral valve) – Prevents backflow of blood into left atrium when left ventricle pumps blood to body
Chordae tendineae
Papillary muscles
Close-up view mitral valve
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23. Dissection 101: Sheep Heart Exposing the Aortic Semilunar Valve
(YouTube Version)
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24. Dissection 101: Sheep Heart Aorta L. V.
Use a probe to locate the aorta; then cut the left ventricle along the probe exposing the aortic semilunar valve
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25. Dissection 101: Sheep Heart Aorta
Aortic semilunar valve – prevents backflow of blood from aorta into left ventricle
Mitral valve
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26. Dissection 101: Sheep Heart Produced by Dakota State University
and South Dakota Public Broadcasting
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