Lec 5 - MCB 136 Professor Terry Machen 3/10/09 Lecture 15...

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MCB 136 Professor Terry Machen 3/10/09 Lecture 15 ASUC Lecture Notes Online is the only authorized note-taking service at UC Berkeley. Do not share, copy or illegally distribute (electronically or otherwise) these notes. Our student-run program depends on your individual subscription for its continued existence. These notes are copyrighted by the University of California and are for your personal use only. D O N O T C O P Y Sharing or copying these notes is illegal and could end note taking for this course. LECTURE Constriction of Arteriolar Smooth Muscle: There are a number of figures that I will change just a little as I go through. I will post them on the website so that those of you who miss things can catch up on bSpace. Today we’ll talk about cardiovascular regulation. Basically what that means is that I will be going through the rest of the mechanisms for how blood flow to the capillaries, arterioles, and so forth maintains its proper balance to increase or decrease the amount of flow when appropriate. I will first go through a bunch of mechanisms and then regulation of blood pressure. I will mention these equations here that the GSIs will go over in discussion sections. Page 59 has to do with regulation of blood flow into and out of arterioles through constriction and dilation. The control of all this is sort of confusing and hard to get it all in one place. I’ve tried to do them on these next few slides. The arterioles in general are regulated by sympathetic constriction and dilation. The constriction is not uniform – it’s not in all vessels. In general it causes constriction, and you don’t need to remember the alpha receptor, but there are exceptions. The exceptions are: the brain, which isn’t really regulated much, but it is regulated according to CO 2 content and blood pH. Also, the coronary – blood flow to the heart, skeletal muscle, and liver, goes in the opposite direction. Instead of constricting, it dilates. If you think about this in terms of fight or flight emergency, what you want to do is increase blood flow to the places where you will need to beat your heart faster, your skeletal muscles are going to be working, and your liver is going to be pumping out glucose into the blood stream. Then there are a few hormones that also cause constriction, but we will ignore those for the time being. I will mostly talk about sympathetic and parasympathetic stimulation. Sympathetic stimulation releases epinephrine (E) and norepinephrine (NE), which cause the muscle, heart, and liver to dilate. Parasympathetic stimulation can also cause dilation, in two ways. In some vessels it causes a reduction in NE output inhibits restriction. It increases dilation by inhibiting restriction. Also, there is EDRF. ACh, the parasympathetic neurotransmitter, can also cause the release of nitric oxide and cause relaxation. This doesn’t happen everywhere, but happens in at least some blood vessels. Another way to dilate the blood vessels is
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Lec 5 - MCB 136 Professor Terry Machen 3/10/09 Lecture 15...

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