Cardiovascular and Respiratory Lab

Dissection Protocol and mini-lab outline

Dissection Instructions for Gross Anatomy

1. Make an incision with your scalpel three inches below the vibrissae on the ventral surface.

2. Cut through the muscle layers with the scalpel in a straight line down the sagittal plane to a point one inch anterior to the umbilicus (cut 1 on next slide).

3. Go back with the scissors and cut through the sternum. 4. At the area parallel with the forearms cut on the

horizontal or transverse plane to the peripheral trunk. Follow the same procedure at the level of the diaphragm (cut 3 on next slide).

Stop – Observe – Draw Ventral Thoracic cavity in situ and label all visible structures. Note observations below your drawing.

Notes on Gross Anatomy

• Under your drawing make the following observations. – How is the heart oriented?– Is there a difference in the right and left lung?– Where is the diaphragm? Is it attached to

anything?– Other than the heart and lungs can you locate

any additional structures? If so label them on your diagram and indicate with a star.

Heart and Lung Removal1.Carefully locate the top of the thoracic cavity. Locate the

larynx with your finger. Gently remove the remaining muscle and glandular tissue from the larynx and follow it down clearing the top of the trachea as well.

2. Once you can clearly see the full respiratory tract, make an incision at the top of your larynx and begin removing the respiratory system and heart from the pig.

3. When removed, you can put your pig back in the bucket, but you will need to keep the removed organs in your pan.

4. Draw the removed organs in both a dorsal and ventral view labeling all identifiable parts on the lungs, heart and respiratory passages. Based on what you are seeing and feeling create predictions about the types of histology that exist in the following structures that may support the functions: Larynx, trachea, lungs, veins, arteries, heart.

Dissection of the Heart

1.If the pericardial membrane is still intact, remove it from the heart. Use a teasing needle and forceps carefully dissect the heart away from the rest of the viscera. The arteries will appear red and the veins blue because the pig has been double injected with latex.

2.Carefully remove the heart by cutting the arteries and veins. Try to leave some short pieces attached to the heart.

Observations of Blood Supply

• Observe the orientation of the blood supply coming into and leaving the heart.

• Draw the removed heart in the ventral and dorsal view. This is a form of observation/data for biological sciences. This will allow you to follow blood supply. You should designate blood vessels with a B or R to indicate color of the latex within.

• Label: Superior and Inferior vena cava, rt.& lf. Atria, rt. & lf. Ventricle, Cardiac veins, Coronary arteries, Pulmonary arch, Aortic arch, rt. & lf. Pulmonary arteries and veins.

Dissection Instructions for Gross Anatomy Internal

• Cut the heart in half along the frontal plane into dorsal and ventral halves.

• Draw both halves. Identify and label the following structures: Rt. and Lf. Atria, Rt. and Lf. Ventricles, Tricuspid valve, Bicuspid (mitral) valve, Pulmonary trunk, Aorta, Vena Cava (inferior and superior), Interatrial septum, interventricular septum.

• Reflect below your drawing. Are you seeing a clear separation of colors from the injection of latex? In other words, is there one side that is blue and another red? If not, why might this be the case. How does fetal and adult circulation differ?

Respiratory System

• Now that the heart is removed you should see the full respiratory system. Draw the removed organs in a dorsal and ventral drawing labeling: Larynx, Trachea, Right and Left Primary Bronchi, Rt. And Lf. Cardiac Lobe, Rt. And Lf. Diaphragmatic Lobes, Rt. Apical Lobe, Rt. Intermediate Lobe, and the Diaphragm.

Structure Dissections:

• Larynx: observe the epiglottis. Draw it (superior view) at the top of the larynx (glottis) and esophagus and label all three pieces.

Your final Cardiovascular/Respiratory Lab Observations shouldInclude:

1 In situ drawing of both systems with additional structures and observations1 ventral view of the removed organs with labels and observations1 dorsal view of the removed organs with labels and observations1 dorsal and 1 ventral view of external heart with blood flow indications1 internal drawing of both halves of sectioned heart with observations1 dorsal view of the respiratory structures1 ventral view of the respiratory structures1 superior view of the larynx

Drawings will be assessed on the Lab Drawing Rubric.