The Circulatory System: The circulatory system delivers oxygen and nutrients to tissues and removes carbon dioxide and waste from tissues.
Blood circulation: Pulmonary Circuit - circulation between lung and heart releases carbon dioxide. Systemic Circuit - circulation between the heart and body delivers oxygen and nutrients and also picks up waste.
The Heart: Anatomy and Conduction: The main pump in the cardiovascular system which generates the pressure required to move blood through the system.
SA node: The heart has a unique, automatic electrical conducting system. The central nervous system (CNS) modulates the rate of contraction of the heart, but the heart can generate and maintain its own rhythm independent of the CNS. Sinoatrial node contains pacemaker cells, which create action potentials at a frequency that results in a normal heart rate of 70-80 beats/minute.
Electrocardiography: The electrocardiogram detects the electrical activity of each heartbeat as it develops over time. The P wave represents the depolarization as it spreads over the atria. The QRS complex corresponds to the current that spreads over the ventricles. The T wave represents the repolarization of the ventricles, during which time they become ready for the next contraction.
Oxygen Delivery to the Tissues
Blood pressure is generated by the heart and facilitates delivery of nutrients to the body.
Capillaries are the smallest blood vessels, where exchange takes place. Passive diffusion lets oxygen/ nutrients out of the blood into the tissue, and lets carbon dioxide/ waste out of the tissue into the blood. Hydrostatic pressure is caused by the blood pressure generated by the heart beating. Na+ and other electrolytes cause osmotic pressure.
Blood & Blood Vessels
Smooth muscle around arterioles modulates blood pressure by changing peripheral resistance. If systemic blood pressure is decreased, neuromodulation of the arterioles causes vasoconstriction, which, in turn, causes an increase in blood pressure.
Blood is made up of the following components: plasma contains water and proteins, red blood cells, white blood cells and platelets. Coagulation is an important process in which soluble proteins form an insoluble clot.
Oxygen is delivered to the tissues bound to hemoglobin. Hemoglobin is a metalloprotein, made up of 4 globin polypeptide chains with 4 imbedded oxygen-binding heme molecules.