Circulatory System

Left atrium

Chamber on the LEFT side of the heart where blood from the lungs enters

Left ventricle

Chamber on the LEFT side of the heart where blood is pumped into the body and oxygenated

Pulmonary veins

Vessels on the LEFT side that take blood from the lungs into the left atrium; blood is oxygenated

Aorta

Blood vessel on the LEFT side that takes blood from the left ventricle to the rest of the body; blood is oxygenated

Bicuspid atrioventricular valve

Valve on the LEFT side that separates the left atrium from the left ventricle and prevents backward blood flow

Aortic semilunar valve

Valve on the LEFT side that separates the left ventricle from the aorta and prevents backward blood flow; blood is oxygenated

Deoxygenated blood

Blood from the body that flows through the vena cavae, right atrium, tricuspid valve, right ventricle, and pulmonary semilunar valve before reaching the lungs

Oxygenated blood

Blood from the lungs that flows through the pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, and aorta before reaching the body

Systemic Pathway

Pathway that moves oxygenated blood to the rest of the body via the aorta and returns deoxygenated blood from the body to the heart via the vena cavae

Pulmonary Pathway

Pathway that moves deoxygenated blood to the lungs via the pulmonary arteries for gas exchange, and returns oxygenated blood back to the heart via the pulmonary veins

Coronary Pathway

Pathway that provides oxygenated blood to the heart through the coronary arteries branching from the aorta, and returns deoxygenated blood to the pulmonary system through the coronary veins

Arteries

Blood vessels that carry blood AWAY from the heart, except for pulmonary arteries, with highly elastic walls that help maintain blood flow in one direction

Capillaries

Smallest blood vessels with walls only 1-cell thick, allowing material exchange like gases, fluids, and nutrients; found throughout the body in a fine network

Venules

Small veins connecting capillaries to larger veins

Veins

Blood vessels that carry blood TOWARDS the heart, except for pulmonary veins, with thin walls and one-way valves to prevent flow reversal

Sinoatrial (SA) node

Bundle of specialized muscle tissue in the right atrium wall that acts as the body's pacemaker by generating electrical signals for heart contraction

Atrioventricular (AV) node

Node that transmits signals from the SA node through specialized fibers like the Bundle of His and Purkinje Fibres to cause ventricles to contract and pump blood

Cardiac cycle

Heart cycle with two phases: Systole (ventricles contract) and Diastole (ventricles relax); includes the closing of valves to prevent blood flow back into the heart or arteries

Electrocardiogram (ECG)

Tool that tracks the electrical signals in the heart nodes to monitor heart activity

Blood Pressure

Pressure exerted by blood against vessel walls, measured in mmHg; includes systolic pressure (during ventricular contraction) and diastolic pressure (during ventricular relaxation)

Heart Rate

Number of heart beats per minute

Stroke Volume

Volume of blood pumped per heart beat, measured in mL/beat

Cardiac Output

Volume of blood pumped per minute, calculated by multiplying heart rate (beats/min) by stroke volume (mL/beat)

Functions of Blood

Includes transportation of gases, hormones, nutrients, and waste; homeostatic regulation through vasodilation, vasoconstriction, and clotting; and disorders like hemophilia and leukemia