 Welcome to nursing school explain in this second part of the process of pharmacokinetics How medications move through the body or how medications affect the body? So medications usually get absorbed first then they get distributed then they get metabolized and excreted So today we'll be focusing on the second part on Distribution but check out my other videos about the other topics over here so when we talk about distribution it means that The medication is being transported from the bloodstream once it's been absorbed to the intended site so whatever cell we are targeting to have a certain response and The distribution depends on several factors So any kind of vascular disease will inhibit the distribution Cardiac disease as well because then the pump is not functioning that helps to transport the medication to the site or any kind of States of decrease perfusion and so think about somebody who is maybe in a shock state in a hypobolimic shock That just does not have a lot of blood volume in their system The medication distribution is going to be inhibited by that and then we have to Consider the concept of permeability so permeability medications are either lipid or water soluble and lipid soluble medications they pass easily through the phospholipid bilayer Where water soluble? medications have difficulty passing through the phospholipid bilayer and Remember from your physiology class. I know for some of you it might have been a while this phospholipid bilayer is the cell membrane and so The there is an extracellular and an intracellular component because this is just the surrounding membrane of any cell and it has these Hydrophilic heads and the hydrophobic tails and on the other side the tails are first and the Hydrophilic heads are on the inside so it has this bilayer by meaning to this phospholipid bilayer and it is impenetrable to water so now That's why lipid soluble medications can pass through easily and water soluble medications not so much But we also have certain protein channels here and protein channels They act like a tunnel imagine you want to go from point A to point B And there's a big mountain that you can't get over so the protein channel serve like a tunnel that help us facilitate the the distribution of the medication into the cell and So like I said the phospholipid bilayer is impenetrable to water and these protein channels Mean that the medication binds to albumin, which is a plasma protein one of the most abundant ones and the distribution However depends on the availability of the binding sites So if there is not enough binding sites to bind the albumin that has now bound the medication The medication will stay in the bloodstream and therefore the patient might become toxic with this medication Circulating around in the bloodstream and not being able to be carried To the inside of the cell through this phospholipid bilayer to do to have its desired effects Now one more important part here is that the blood brain barrier as well as the blood placental and the blood testicular barrier they It says here that the lipid soluble medications can pass through and water soluble cannot pass through so for regular Cells besides the brain the placenta and the testicles with these gated protein channels medications can pass through But the blood brain barrier the placenta and the testicles are laid out in such a way that these things cannot pass through And that is mostly because our physiology has designed us in such a way that we don't want any harmful Fungi, toxins, bacteria, viruses to be passing through and affect our brain and our reproductive organs So again lipid soluble can and water soluble cannot pass through at all Which is then we have to think about different ways of making that happen So thank you for watching the second video in the pharmacokinetics series Also, check out the other videos on absorption metabolism and excretion So you have a little bit of a better understanding how medications work and how they are processed through the body And what the different factors are that affect the medication availability and its effect it can have Thanks for watching. See you soon