CIRCULATORY - CARDIOVASCULAR

VEINS



Circulatory System:
" INTRODUCTION
" COMPONENTS OF THE CIRCULATORY SYSTEM
" OPERATION AND FUNCTION
" Systemic Circulation
" Pulmonary Circulation
" Additional Functions
" Blood Pressure
" DISEASES AND DISORDERS
" HEART
" BLOOD
Vasculature System:
" Arteries
" Veins
" Capillaries
" Vasculature of the Arm
" Vasculature of the Head
" Vasculature of the Leg
" Vasculature of the Torso

Veins

Vein, in anatomy, blood vessel that conducts the deoxygenated blood from the capillaries back to the heart. Three exceptions to this description exist: the pulmonary veins return blood from the lungs, where it has been oxygenated, to the heart; the portal veins receive blood from the pyloric, gastric, cystic, superior mesenteric, and splenic veins and, entering the liver, break up into small branches that pass through all parts of that organ; and the umbilical veins convey blood from the fetus to the mother's placenta. Veins enlarge as they proceed, gathering blood from their tributaries. They finally pour the blood through the superior and inferior venae cavae into the right atrium of the heart. Their coats are similar to those of the arteries, but thinner, and often transparent.

Veins

Veins are blood vessels that return blood to the heart from other parts of the body. This false-color electron micrograph shows red blood cells packed into a capillary, the smallest type of blood vessel. Blood flows from the capillaries into veins after oxygen has been exchanged.

World Health Organization