Focus-Science and Technology - - Q & A -

Your skin’s most im­por­tant job is to keep out the bil­lions of harm­ful bac­te­ria that swarm over ev­ery sur­face. Any wound that pen­e­trates the der­mis layer and causes bleed­ing will al­low bac­te­ria to get in, so we have evolved a pre­cisely co­or­di­nated mech­a­nism to seal up the gap as quickly as pos­si­ble. The heal­ing process uses ex­tra col­la­gen pro­tein for the re­pair, so the new skin is ac­tu­ally stronger than be­fore. This shows as a vis­i­ble scar.

SMALL CUT 1. Hae­mosta­sis

When the skin is punc­tured, blood ves­sels con­tract and platelets re­lease fib­rin pro­teins that tan­gle to­gether to form a clot and seal the wound.

2. In­flam­ma­tion

Next the blood ves­sels ex­pand again to al­low white blood cells to flock to the wound site. These at­tack any bac­te­ria that got past the clot.

3. Pro­lif­er­a­tion

After a few days, fi­brob­last cells ar­rive and pro­duce col­la­gen. This pro­tein acts like a scaf­fold, while the der­mis cells re­pro­duce to close up the wound.

LARGE CUT 1. Keep it clean

Wash the open cut to pre­vent bac­te­ria get­ting trapped in­side. Don’t use dis­in­fec­tant be­cause this will kill your own cells that are try­ing to re­pair the wound.

2. Seal it

A plas­ter keeps dirt out and helps the clot form. If the wound is still bleed­ing after 10 min­utes with a plas­ter on, you may need stitches.

3. Scar­ring

The skin con­tin­u­ally re­builds the col­la­gen ma­trix for up to a year after the cut. This scar tis­sue will fade slightly for an­other year after that.

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