Yes they are tubes. They are filled with blood.
yes
Yes, but it will be a little darker inside the veins.
because you blood is inside your veins.
blood
The internode space. The space between the two leafe nodes. The spaces between leaf veins are called areoles.
Veins have thinner walls compared to arteries. They also have larger lumens than arteries which is the space inside the vessel. Lastly they have one-way valves to help keep the blood flowing in one direction.
Veins, in most animal circulatory systems, carry deoxygenated blood from the tissues back to the heart.The exception are the pulmonary veins, which carry oxygenated blood to the heart.There is also a lining inside the veins made of epithelial tissue.
The blood in veins is not under direct pressure from the heart. It has little valves inside to prevent blood from flowing backwards away from the heart. These valves inside the veins prevent the backflow of blood in veins. They encourage the one-directional flow of blood to the heart.
device to view inside veins
There are three types of veins, superficial veins that are just beneath the surface of the skin, deep veins that are large blood vessels found deep inside muscles, and perforator veins that connect the superficial veins to the deep veins.
intra (inside) vascular (veins).. what is found in your veins? Cut it to find out!
Valves in the veins prevent the blood from flowing backward or from pooling.
Inside of your veins and arteries.