If dark red blood is flowing in a steady stream, where is the blood coming from?

If dark red blood is flowing in a steady stream, where is the blood coming from?

• A. Veins
• B. Arteries
• C. Capillaries
• D. Lymphatic system

Answer: (A)

The main idea here is that the color and flow pattern of bleeding tell you where it’s coming from. Dark red blood indicates deoxygenated blood, and a steady, non-pulsatile flow is typical of a venous bleed. Veins operate at much lower pressure than arteries, returning blood to the heart, so when they bleed, the flow tends to be continuous and steady rather than spurting. Arteries, on the other hand, carry oxygenated, bright red blood under higher pressure, and arterial bleeding is usually pulsatile or spurting due to that pressure. Capillaries tend to ooze blood slowly rather than flow in a steady stream. The lymphatic system carries lymph, not blood, so it wouldn’t present as a steady stream of dark red blood.

The main idea here is that the color and flow pattern of bleeding tell you where it’s coming from. Dark red blood indicates deoxygenated blood, and a steady, non-pulsatile flow is typical of a venous bleed. Veins operate at much lower pressure than arteries, returning blood to the heart, so when they bleed, the flow tends to be continuous and steady rather than spurting.

Arteries, on the other hand, carry oxygenated, bright red blood under higher pressure, and arterial bleeding is usually pulsatile or spurting due to that pressure. Capillaries tend to ooze blood slowly rather than flow in a steady stream. The lymphatic system carries lymph, not blood, so it wouldn’t present as a steady stream of dark red blood.