A sheep has so much fat around it's heart to protect the valves in  the heart. There is also a lot of fat there to maintain the body  temperature of the heart.
Definition and Causes. Upper respiratory tract infection (URI) is a nonspecific term used to describe acute infections involving the nose, paranasal sinuses, pharynx, larynx, trachea, and bronchi.The prototype is the illness known as the common cold, which is discussed here, in addition to pharyngitis, sinusitis, and tracheobronchitis.efinition and Causes. Upper respiratory tract infection (URI) is a nonspecific term used to describe acute infections involving the nose, paranasal sinuses, pharynx, larynx, trachea, and bronchi.
Bacterial or Viral Infections of the Respiratory Tract. Viral illnesses are the most common cause of upper respiratory symptoms. Symptoms of a viral illness often appear over several hours without prior illness. Common viral illnesses include colds and the flu (influenza). Bacterial respiratory tract infections are less common than viral infections. Bacterial infections may develop after a viral illness such as a cold or the flu. Bacterial infections may affect the upper or lower respiratory system, and symptoms tend to localize to one area. The most common sites of bacterial infections in the upper respiratory system are the sinuses and throat. Pneumonia is the most common bacterial infection of the lower respiratory system.