Which system includes the heart and blood vessels?

The heart and blood vessels are integral components of the circulatory system. This system is primarily responsible for transporting blood throughout the body, facilitating the delivery of oxygen and nutrients to tissues while removing waste products like carbon dioxide. The heart acts as the pump that drives the circulation, and the blood vessels, which include arteries, veins, and capillaries, form a vast network that carries blood to all parts of the body.

The circulatory system plays a critical role in maintaining homeostasis, regulating body temperature, and supporting the immune system. Understanding this system is fundamental in veterinary medicine, as it applies to the health and treatment of animals, particularly in cases involving cardiovascular conditions or surgeries.

The other options pertain to different body systems that do not encompass the heart and its associated vessels. For example, the nervous system is focused on the brain, spinal cord, and nerves, responsible for transmitting signals throughout the body; the gastrointestinal system involves organs related to digestion and nutrient absorption; and the integumentary system includes the skin, hair, and nails, which protect the body and help regulate temperature. Each system has distinct functions and structures, highlighting the importance of the circulatory system in overall physiology.