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Urinary system.

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So the urinary system is really quite simplistic when you compare it to other bodily systems.

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However, it's fundamental when it comes to the function and regularity within your body.

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So as you can see on the image, the urinary system is made up of 
two kidneys right-hand side and left hand side,

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Ureter down into the bladder, and then urethra 
which excretes the waste products from your body.

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So the overall functions then of the urinary system is that it 
helps us to regulate within our body and maintain homeostasis.

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So it helps to regulate your blood volume, the regulation of lots of different types of electrolytes, 
including sodium potassium, chlorine,

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as well as regulating the electrolyte of hydrogen, 
which in turn regulates your acid base balances

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and your water balance hydration within the body.

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And all of this takes place in a really important structure, which is housed inside the kidney, 
known as the nephron.

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The nephron is housed within the structure of the pyramid inside the kidney.

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So we're going to have a look at a kidney dissection in order to see the pyramid 
where these all important nephrons are living.

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So in terms of physiology, the kidneys are located on the posterior, the back of the body.

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So when we're working down the ribs, you're looking at rib 10, 11, and 12 in the small of the back.

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and the kidneys are located in the lateral, moving away from the midline,


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the lateral aspect of the body

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with ribs, 10, 11, and 12 acting as a form of protection for that organ.

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The kidney itself in humans then on average is around 11cm 
in length, 6cm in width and approximately 3cm in depth.

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So when we look at the external structures of the kidney, 
we can actually see this really lovely, dark red, almost brown in its colour appearance

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and this is known as the cortex, which again, provides a lot of protection for this organ.

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When we turn it over, we can actually see we've got a slightly different structure 
and this is the ureter.

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And the ureter is what's bringing the waste products that's been filtered out of the blood in the kidney

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away to the bladder and lets the body excrete that waste product through urine.

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Ordinarily, which isn't on this sample, we would have a renal artery, 
that's bringing blood into the kidney

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where the filtration of electrolytes, hydrogen ions,
acid based balance, water and blood volume takes place.

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Those can be reabsorbed into the blood 
or any waste products then come through the ureter or into the renal vein,

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which brings that blood away from the kidney to the rest of the body.

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In order to make the incision, we're going to work on the lateral aspect of the kidney, 

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working in towards the medial aspect on the coronal plane, so it would open up like a book.

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And then once we can see inside, we could see those all 
important pyramids, which are housing the nephrons.

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So in completing your dissection, there are several pieces of equipment that you need to use. 

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So first, when you are using your scalpel, you need to be 
extremely careful with the sharp blade that's involved

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that you are courting the organ that you're working with and not yourself.

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So always when you're doing these dissections, 
make sure that the blade is working away from you and your fingers.

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So when we're making the incision, as I say,
we're going to work on the most lateral aspect down the Coronal plane.

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So the kidney is going to be opened up just like a book.

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Into the organ, mindful of your fingers.

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If you were working in pairs, doing the dissection, 
one person would complete this task with the other person, nowhere near that organ. 

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So following the line that you've made on your first incision, 
continuing that through...

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medially into the body.

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So using your forceps, you can start to walk up and up the organ from your incision, 
making sure you're staying on that coronal plane.

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And continue through and as you're cutting it open, 
you can see already, you start see a lot of color changes

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and these are those all important structures inside your kidney,
the pyramids, medula and renal pelvis.

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You may see some liquid appearing just like now, which is urine still within the kidney.

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So equally, you will get quite a potent fragrance.

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So again, staying on that plane, you can see now opening up the organ it's quite symmetrical 

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And we can see the structures inside.

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When we look at the internal structures of the kidney, 
we can see that we've got this darker brown margin

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being the cortex that we saw on the external structure, 
which provides protection for the kidney.

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Moving further in then, we can see quite a large area 
of this pinky white material, which is the renal pelvis.

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And the renal pelvis then is elongated towards the cortex.

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These elongations are known as the Medula 

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and it's in between Medula that we see this very red structure known as the renal pyramid.

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And it's inside the pyramid that we find the nephrons 
and it can be up to 2 million nephrons per pyramid.

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So the nephron is what's the most important part 
being the site of filtration, reabsorption, secretion, and excretion.

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And the waste products then that are not reabsorbed back into the blood.

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Are excreted from individual nephrons to the Medula. 

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This continues down into the renal pelvis 
and then we can see with the ureter that waste product goes through the ureter

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out away from the kidney to the bladder and then removed from the body via the urethra. 

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So as I said at the beginning, this is a really simple system
within the body, but comparable, it's fundamental to your functions and regulations as well. 

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So we've seen this very simplistic kidney when we open it up in dissection, 
we can appreciate the complexity internally, 

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which then gives to the regulations of your blood volume, 
electrolytes, water, and acid base balances 

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and removing those waste products from your body all down to those nephrons inside the pyramids.