Cardiovascular

=** Even the Tin Man agrees: You can't live without the heart ! **= media type="custom" key="4879773" align="center"

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=** What is the Cardiovascular System? **= The cardiovascular system, also referred to as the circulatory system, consists of the main organ of the body - the heart in conjunction with the capillaries, arteries, and veins, arterioles and venules. Adults have about 60,000 miles of blood vessels. The heart itself has three tissue layers: the epicardium, (outer layer) the myocardium, (middle layer) and endocardium (innner layer). The heart continuously goes through a cycle of contraction and relaxation. The contraction phase is called systole. The relaxation phase (when the heart's chambers are re-filling) is called diastole. When your blood pressure is measured at the doctor's office, they are actually measuring the pressure when your heart is in the each phase. = What Does the Cardiovascular System Do? = The cardiovascular system works to maintain homeostasis in the body through blood circulation. The heart acts as a pump that propels blood throughout the body, sending oxygen, nutrients, and hormones (produced by the endocrine system) to the places where they are needed. It also the action of the heart that carries carbon dioxide and other wastes from the tissues. Heart rate is controlled by signals transmitted from the autonomic nervous system (which controls automatic functions) to the sinoatrial (SA) node. This system can double your heart rate in three to five seconds. =** What are the Parts of the Cardiovascular System? **= The cardiovascular system consists of two parts. There is the pulmonary system, which moves the blood in a continuous cycle from the heart, to the lungs, and back to the heart again. Another component is the systemic circulation, which gives nutrients to various tissues throughout the body. The heart has four chambers: two atria and two ventricles. During a heartbeat, the two atria recieve the blood and the two ventricles expel the blood. The two atria are divided by the atrial septum, and the two ventricles are divided by the ventricular septum. = Why is the Cardiovascular System Important? = The cardiovascular system is the most vital in the body. Without it, our essential bodily functions would fail, and ultimately lead to death.

All Information and Pictures Credited to... Google Image Search Anthony's Textbook of Anatomy & Physiology: 17th Edition Glogster.com Image Database http://kidshealth.org/parent/general/body_basics/heart.html# http://www.fi.edu/learn/heart/systems/pulmonary.html http://kidshealth.org/teen/your_body/body_basics/heart.html http://www.fi.edu/learn/heart/systems/systemic.html []