Thyroid Gland

Thyroid Gland: the oval shaped gland is found in the neck ventral to the trachea and just below the larynx.

Bronchi

The trachea branches into each lung. These two tubes are called bronchial tubes. Inside the lungs these branch into smaller bronchioles that end with a grape-like cluster of air sacs or alveoli where oxygen and carbon dioxide are exchanged with capillaries.

Diaphragm

Since the pig is already open from the digestive system dissection, examine the diaphragm, a sheet of muscle that stretches across the abdominal cavity and separates it from the thoracic cavity where the lungs are located and in the center is the heart. It can be found right above the stomach and liver and under the lungs and heart. Once you locate this, the respiratory and circulatory is right on top. You may need to cut through the pig's sternum and expose the chest cavity (thoracic cavity) to view. You will need to cut up under the pig's throat and neck and make two more lateral incisions in order to fold back the flaps of shin covering the throat to expose the thoracic.

Pulmonary Veins

Pulmonary Veins: Consists of four vessels that return form lungs to the left atrium of the heart.

Pulmonary Arteries

Pulmonary Arteries: The pulmonary arteries carry deoxygenated blood from the heart to the lungs. These are the only arteries that carry deoxygenated blood. It begins at the base of the right ventricle then branches into two pulmonary arteries (left and right), which deliver de-oxygenated blood to the corresponding lung.

On the ventral surface of the heart passing dorsally and to the left is the large pulmonary artery. It originates in the right ventricle. Try tracing it its two branches to the lungs.

Pulmonary Trunk

Pulmonary Trunk: Is the artery that goes from the right ventricles to the lungs. It has two main branches (right and left pulmonary arteries).

Aorta

Locate the aorta, the largest systemic artery of the body. It leaves the left ventricle, curves to the left, dorsal to the pulmonary artery, and continues dorsally in a posterior direction along the left side of the vertebral column. The proximal curved portion of the aorta is called the aortic arch, while the next segment of the aorta within the thorax is known as he thoracic aorta.