because it has very small lumen
Glucose and oxygen are transported from the blood to cells through capillary walls by a process called diffusion. The concentration gradient between the blood and the cells allows these molecules to passively move across the capillary walls. Once inside the cells, glucose and oxygen are used for energy production through cellular respiration.
They are called capillary vessels. Some are so narrow that hemoglobin cells have to queue to go through them.
Because the glucose in capillary blood is not fully delivered to the cells yet. Once the blood leaves the capillary and enters the vein, the glucose has then been delivered to the cells and the blood is considered used.
The round cells that move in the blood capillaries are called RED BLOOD CELLS.
I Believe so
The blood cells must move through the capillaries in a single file line because the diameter of the capillary is only slightly larger than the diameter of the blood cells - there isn't room for two blood cells to go through side by side.
Capillary
Red blood cells are concaved (dented) to increase surface area. Their shape also allows them to bend and squeeze into and through those tiny little capillary blood vessels.
Capillary endothelium
'c' heart pumps oxygen rich blood, 'a' oxygen rich blood arrives at capillaries, 'd' oxygen moves through capillary walls, 'b' oxygen enters body cells.
Capillaries, which are only one cell thick. The walls are semipermeable to the cell membranes in the body and are so narrow that red blood cells must pass through in a line, one behind the other. Oxygen and nutrients diffuse from the capillary to the body cells at the arterial end of the capillary while CO2 and other metabolic wastes enter the capillary at the venous end, because of diffusion gradients between the cell and the plasma and cells in the capillary.
capillary tube is not really sealed securely. there are tiny gaps between the cells that forms the wall of cappilary tubes which allows certain materials to pass through (eg. nutrients, oxygen, carbon dioxide). It is just not permeable to your blood cells cause if it does, your body will be insufficient of blood cells