Below is information about the structure and function of the feline cardiovascular system. We will tell you about the general structure of the heart and circulatory system, how the cardiovascular system works in cats, common diseases that affect the cardiovascular system, and common diagnostic tests performed in cats to evaluate the cardiovascular system.
What Is the Cardiovascular System?
A cat’s cardiovascular system (or circulatory system) is the system responsible for circulating blood throughout the body. It consists of the heart and blood vessels, namely arteries, veins and capillaries.
Where Is the Cardiovascular System Located?
The heart is located in the chest between the right and left lungs and is contained in a very thin sac called the pericardial sac. The heart extends approximately from the 3rd to the 4th rib of the cat.
Blood vessels leave the heart and form a conduit system throughout the body that carries blood to all organs, tissues and cells.
What Is the General Structure of a Cat’s Cardiovascular System?
The heart is the central organ that contracts rhythmically to pump blood continuously through the blood vessels. The rhythmic contraction is commonly referred to as the “heart beat”. The heart consists of four chambers:
Arteries are strong, muscular blood vessels that carry oxygen-rich blood from the heart to various parts of the body. The wall of an artery consists of an outer coat (tunica adventitia), a middle coat (tunica media), and an inner coat (tunica intima). Small blood vessels that branch off the arteries are called arterioles.
Veins are thin blood vessels that carry blood from various parts of the body or organs back towards the heart. Like arteries, veins have three coats, but the coats are not as thick. Because of their thin walls, veins are very compliant, and their volume and size vary with blood pressure. Veins also contain valves, which allow blood flow in only one direction, towards the heart. The valves stop blood from flowing backward towards the organs. Small blood vessels that lead from the capillaries to the larger veins are called venules.
Capillaries are the smallest of all blood vessels. Capillaries are so small, that in many instances only a few red blood cells can pass through the center of the capillary at a time. Capillaries usually lie between the arterioles and venules. Capillary walls act as a membrane that allows various substances to travel between the blood and the tissues. These substances include oxygen, carbon dioxide, water, electrolytes (e.g. sodium, potassium), nutrients, and minerals. The capillaries are the site of the greatest exchange of material between the blood and the tissues of the body.