Human Circulatory System Overview

Study Notes

The circulatory system includes the heart and blood vessels, often referred to as the cardiovascular system.
The heart is a pump that circulates blood through the blood vessels. It has two halves, each with two chambers.
The heart's main function is to transfer oxygen-depleted blood from the body to the lungs and oxygen-rich blood back to the body.
The right side of the heart receives oxygen-depleted blood from the body, pumps it to the lungs for oxygenation, and receives oxygen-rich blood back.
The left side of the heart receives oxygen-rich blood from the lungs, pumps it to the rest of the body, and receives deoxygenated blood back.
The heart is surrounded by a double-layered protective shell called the pericardium.
The heart is composed of three layers: an outer fibrous layer, a middle muscular layer (myocardium), and an inner layer of heart tissue.
The myocardium contracts due to electrical impulses, also known as pacemaker cells, to initiate heartbeats.
The heart supplies the body with nutrients from food and removes waste products.
Blood vessels, including veins, arteries, and capillaries, transport blood throughout the body.
Large veins carry deoxygenated blood from the body to the heart, while arteries carry oxygenated blood from the heart to the body.
Capillaries are the smallest blood vessels and facilitate the exchange of nutrients and waste between the blood and body tissues.
The heart's main pumping chambers are the left and right ventricles.
The heart's electrical system is controlled by the sinoatrial node and the atrioventricular node.
The heart contracts and relaxes in a systematic manner to ensure efficient blood circulation.
The heart's valves prevent backflow of blood and maintain unidirectional blood flow.
Blood pressure is regulated by various factors, including the heart's pumping ability and the diameter of blood vessels.
The circulatory system plays a crucial role in maintaining homeostasis and supporting the body's metabolic processes.