Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: chris on 17/05/2017 20:17:58

Title: Why might a nose bleed produce purple-coloured blood?
Post by: chris on 17/05/2017 20:17:58

Michelle asks:

What does it mean when someone's nose is bleeding and the blood is coming out purple?

What do you think?

Title: Re: Why might a nose bleed produce purple-coloured blood?
Post by: evan_au on 17/05/2017 21:50:37

Blood from veins (venous blood (https://en.wikipedia.org/wiki/Venous_blood)) has a lower oxygen content than blood in arteries, and is a darker, more purple color than the bright red blood of arteries.

If someone has poor lung function, it is possible that even their arterial blood has low oxygen content, and arterial blood could appear to have a blue tint too, as well as their lips.