Circulatory and Respiratory

 The next day we hit the respiratory and circulatory systems. We cut from the abdomen cavity into the thoracic cavity and found it heavy in fascia. When we opened the rib cage we cut through muscle and connective tissue. We located the larynx which followed by the trachea, (ridged and bumpy appearance) leading to the thyroid gland which is surrounded by the thymus. Attached to the thymus and thyroid gland is the cranial vena cava which leads to the heart and lungs. The heart lies in the pericardial cavity, the red areas are arteries and the blue areas are veins. We gently cut the pericardial sac which is a tough membrane composed of two coelomic epithelial linings, the parietal pericardium and the parietal pleura to expose the heart.  We traveled down to the lungs by following the trachea all the way down. The trachea branched into bronchi which lead to the right and left lobe of the lungs. We observed that the bronchi branch into smaller bronchi called bronchioles. Bronchioles branch into alveoli was so small you cannot see it through the naked eye. Its where the exchange of oxygen and carbon dioxide take place. 

In this picture you can see the cranial vena cava on top and to the right the aorta. Directly beneath the cranial vena cava lies the right atrium and below the right ventricle. The pale pink line towards the bottom is the coronary artery and vein. Opposite of the right atrium is the left atrium and below the left ventricle.