Did you know, it takes a minute for blood to travel around the whole body!?
The human circulatory or vascular system is amazing, carrying an assortment of hormones, proteins, nutrients and also exchanging gases like oxygen and CO2 from cellular respiration e.g. from energy production in the electron transport chain of the mitochondria and the by products of cell growth!
As you can get a glimpse of from the slightly gory image here from Operating Theatre Live, that shows this system injected with resin, the vascular network starts with larger blood vessels that decrease in size to become the tiny complex network of micro capillaries that supply each of the 100,000 hair follicles on the scalp.
In some hair loss conditions such as androgenetic alopecia, also known as male or female pattern hair loss, part of the physiological change reported is the diminished blood supply and subsequent lower oxygen levels reported here as compared with non-affected areas of the scalp.
Many treatments for hair loss aim to improve blood flow and oxygenation to the hair follicles in a variety of different ways and mechanisms to improve and sustain growth of the hair fibre!
Image credit: Operating Theatre Live