Final answer:
The intrinsic control system of the heart involves mechanisms like the SA node within the heart, while the extrinsic control system involves neural and hormonal signals from outside the heart. Both systems work together to regulate cardiac output, which is the volume of blood the heart pumps and is affected by exercise and other factors.
Step-by-step explanation:
The intrinsic and extrinsic control systems are mechanisms by which the heart regulates cardiac output. The intrinsic system refers to mechanisms within the heart itself that respond to changes in blood volume or pressure; this includes the cardiac conduction system, which ensures the heart beats in a coordinated manner. The most prominent feature of the intrinsic system is the SA node (sinoatrial node), acting as the heart's natural pacemaker, setting the rhythm of the heartbeat.
The extrinsic control system involves neural and hormonal signals that originate outside the heart. The cardiovascular centers located in the medulla oblongata of the brain regulate heart rate through the autonomic nervous system. These centers respond to various factors such as exercise, emotional stress, and blood pressure changes by adjusting heart rate and strength of heart contractions. Hormones like adrenaline can also affect the heart rate, and increase cardiac output.
Together, these systems ensure that cardiac output meets the body's demands. Cardiac output is calculated by multiplying the heart rate by the stroke volume, or the amount of blood pumped by the heart with each beat. Factors such as exercise increase cardiac output and heart rate, as the body needs more oxygen and nutrients during physical activity.