How do IM injections enter the bloodstream?

Tachy55

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Can someone explain exactly how medications injected via IM get into the bloodstream? I understand there is a rich supply of blood vessels in muscle, but how exactly does it get into the vascular system. Just through the simple concept of diffusion? I've looked online and have not found the desired answer.
 

Summit

Critical Crazy
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Yes, you are on the right track with diffusion, but it is more complex than that and depends on what was injected. Research the following concepts:
absorption (pharmacokinetics)
capillary wall transport (macromolocules)
cell transport (active and passive) <-very important in general although less so here

This is why A&P I&II should be a requirement (because the prereq is Bio I and anyone who had Bio I knows the answer).
 

E tank

Caution: Paralyzing Agent
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th (2).jpg


Pretend this isn't a cell, but a short axis cross section of a capillary and the red oxygen dots are medicine. Drug moves along a concentration gradient from high to low. A simplification, but you get the idea.
 

phideux

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Magic!
 

Qulevrius

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Yes, you are on the right track with diffusion, but it is more complex than that and depends on what was injected. Research the following concepts:
absorption (pharmacokinetics)
capillary wall transport (macromolocules)
cell transport (active and passive) <-very important in general although less so here

This is why A&P I&II should be a requirement (because the prereq is Bio I and anyone who had Bio I knows the answer).

Bio I touches on it very lightly (only addressing the plasma membrane), but A&P gives much more comprehensive information, including ion channels, osmosis, concentration gradient etc. Just my $.02
 
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