Video Transcript
What type of blood vessels surround and deliver blood to body cells, tissues, and
alveoli?
To answer this question, we first need to understand what body cells, tissues, and
alveoli need from blood.
Alveoli are small sac-like structures found in the lungs. Alveoli are surrounded by a network of capillaries which carry blood to and away from
the lungs. It is here that the oxygen we breathe in moves from the lungs and into the
bloodstream. The oxygen diffuses into the red blood cells, which are then taken away from the
lungs by the capillaries. This oxygenated blood is then taken to body cells, which require oxygen to carry out
cellular respiration. The oxygen diffuses from the red blood cells and into the body cells.
The mitochondria then use this oxygen to break down glucose as part of cellular
respiration, releasing energy in the process. This energy is then used to power important metabolic reactions in the cell and
provide us with the energy we need to function. The reason that capillaries are well adapted to allow the transport of oxygen into
and out of them is because they are only one cell thick. This means that oxygen can easily diffuse across a short pathway, from the alveoli
and into the capillaries. When this oxygenated blood reaches body cells, oxygen can easily diffuse back out of
the capillaries and into the body cells.
Veins and arteries are the other major blood vessels. Substances cannot diffuse easily out of these blood vessels, as their walls are much
thicker than those of capillaries.
So, the type of blood vessels that surround and deliver blood to body cells, tissues,
and alveoli are capillaries.
