the.com/vein
the highway home, hauling tired blood back to refill its tank
means A vein is a blood vessel that carries blood back toward the heart, though the word also stretches to mean a streak of mineral in rock, a mood or style of expression, or a thin branching line in a leaf or insect wing.
from From Latin 'vena,' meaning a blood vessel or, by extension, a streak in stone or wood — the Romans already saw the metaphor running through the body, the earth, and the timber. It traveled into English through Old French 'veine.' The mineral and metaphorical senses ('a vein of gold,' 'in a lighter vein') were carried along inside the word from the very start, riding the same channel.
- low pressure
- Veins carry blood gently, no powerful heartbeat surge needed
- one-way valves
- Tiny flaps stop blood from sliding backward downhill
- blood storage
- Hold roughly 70 percent of your body's blood
- muscle pump
- Leg muscles squeeze veins to push blood upward
- why blue
- Skin scatters light; the blood inside stays red
great saphenous vein — longest vein in human body, runs from foot to groin
superior vena cava — major vein returning blood to heart from upper body
pulmonary veins — four veins carrying oxygenated blood from lungs to left atrium