Circulatory System Overview

The circulatory system is the body's transport system, carrying oxygen, nutrients, and waste throughout the body.

The heart is a muscular organ that pumps blood throughout the body. It pumps oxygenated blood to the body and deoxygenated blood to the lungs.

Arteries carry oxygenated blood away from the heart to the body.

Veins carry deoxygenated blood back to the heart from the body.

Capillaries are tiny blood vessels that connect arteries and veins, allowing for exchange of oxygen, nutrients, and waste between blood and cells.

The pacemaker, or sinoatrial (SA) node, is a group of cells in the right atrium that initiate and regulate heartbeats.

A pulse is the rhythmic expansion and relaxation of an artery wall caused by the heart's contractions.

Blood pressure is the force exerted by blood against the walls of blood vessels.

Deoxygenated blood flows from the right atrium to the right ventricle, then pumped to the lungs via the pulmonary arteries. Oxygenated blood then travels from the lungs to the left atrium, then the left ventricle, and finally pumped to the aorta to deliver oxygen to the body.

Oxygen-rich blood is carried away from the heart in large blood vessels called arteries. They have three layers: an outer connective tissue layer, a middle smooth muscle layer, and an inner endothelial tissue layer.

Microscopic vessels where exchange of substances and wastes occurs. Capillary walls are only one cell thick, allowing for easy diffusion of substances.

The largest blood vessels, carrying oxygen-poor blood back to the heart. Muscle contraction helps blood flow, and valves prevent backflow.

The clear yellowish portion of blood. It carries glucose, fats, vitamins, minerals, hormones, and waste products from cells.

Red blood cells transport oxygen to all body cells. They contain hemoglobin, an iron-containing protein that binds with oxygen.

Cell fragments responsible for blood clotting. They stick to wounds, release chemicals that form fibrin, and trap blood platelets and red blood cells to stop bleeding.

The body's disease fighters. They are produced in bone marrow and recognize and fight disease-causing organisms. Some produce chemicals to fight invaders, while others surround and kill them.

Antibodies are proteins found in plasma that recognize and bind to foreign substances like red blood cells with different markers, causing them to clump together.

The Rh factor is an additional marker on red blood cells that can cause complications during pregnancy. If a mother with Rh-negative blood is exposed to Rh-positive fetal blood, she will develop antibodies that can affect future pregnancies and potentially damage the fetus's red blood cells.

Atherosclerosis is a condition where arteries become blocked due to the buildup of plaque (blood clots and other matter), reducing blood flow.

Blood clots and other debris can obstruct blood flow in arteries. This can lead to a heart attack or stroke since the heart has to work harder to pump blood, and blood vessels can burst under pressure.

The aorta is the main artery that carries oxygenated blood from the heart to the rest of the body.

The pacemaker is located in the right atrium of the heart and it acts as the natural 'pacemaker' of the heart, controlling the heart rate.

The left ventricle is responsible for pumping oxygenated blood to the body through the aorta.

White blood cells are the key component of blood that fights disease by attacking and destroying foreign invaders like bacteria and viruses.