Identification of External Anatomical Features of a Sheep Heart

Preparation for Dissection

• Materials Needed:
  • Gloves
  • Dissecting kit
  • Dissecting tray
  • Sheep heart specimen
• Preparation Steps:
  1. Cut open the bag containing the sheep heart.
  2. Discard the bag into the trash.
  3. Rinse the heart thoroughly with water to remove preservatives.
  4. Run water into large blood vessels to expel blood clots.

Positioning the Heart for Examination

• Place the heart in a dissecting tray with the anterior surface facing up.
• Some sheep heart specimens may have the pericardial sac still attached.
• Locate the visceral pericardium:
  • Appears as a thin transparent layer on the heart's surface.

Observing Anatomical Features

• Adipose Tissue:
  • Found along the paths of various blood vessels.
  • Located in the loose connective tissue beneath the visceral pericardium.

Anterior View of the Heart

• Orientation: Apex down, base up.
• Key Structures to Identify:
  • Left and right ventricles
  • Left and right atria
  • Coronary sulcus between atria and ventricles.
  • Anterior interventricular sulcus:
    • Contains fat.
    • Removing fat reveals underlying vessels.
  • Pulmonary trunk from the right ventricle.
  • Ascending aorta and brachiocephalic trunk from the left ventricle.

Posterior View of the Heart

• Repositioning: Turn the heart so the posterior side is facing up.
• Key Structures to Identify:
  • Ventricles and atria remain visible.
  • Left and right sides correspond to your own left and right.
  • Posterior interventricular sulcus
  • Superior and inferior vena cava:
    • Both lead to the right atrium.
    • A probe can be inserted in one and exit through the other.