Our Body’s Built-In Filter- Part 2

Hello again!

I’m going to try to finish writing about the urinary system in this post today but there is quite a lot more material to cover so we’ll see how it goes!

So where were we…  I finished going through the basic functions and anatomy of the main organs of the urinary system last time. In this post, I will focus more on the details of how the kidneys filter out our blood to urine. It is quite a fascinating subject in my opinion so this will be fun going through all the details again! You will appreciate your wee so much more after this post (I hope)!!😆

If you have read my earlier post, you should know that the key organ of the urinary system, the star of the show,  are the bean-shaped kidneys. The kidneys are where blood is filtered out into the urine, maintaining our homoeostasis in blood pressure, blood pH, water, electrolytes, and red blood cell production. The kidneys also eliminate waste products such as nitrogenous wastes, toxins, and drugs through the urine.

Nephron drawing by me

The nephron is the functional unit of the kidneys and that is where all the filtration occurs and there are about a million nephrons per kidney! If I had to very briefly explain how the filtration occurs in each nephron, I would say that blood is forced through very narrow blood vessels where some of the fluid gets squeezed into a tube. That fluid then travels through a long tube giving away its nutrients if necessary, which results in urine.  That is basically how urine is produced but there is so much more than that!

Source: Educast

Firstly, let’s begin with blood entering the nephron. I’m not sure if I mentioned this before but anything “renal” has to do with the kidneys. Why did I say that? It is because the blood enters the nephron via the renal artery. It then goes through the afferent arteriole entering the glomerulus. The rest of the blood then exits the glomerulus through the efferent arteriole.

However,  when blood reaches the glomerulus, some fluids in the blood are pushed out into the bowman’s capsule where the filtration begins. As you can see in the diagram below, the filtered fluids start travelling from the bowman’s capsule through a long tube which has different parts and names to it. The fluids travel through the proximal convoluted tubule (PCT), down the descending limb of the loop of Henle, up the ascending limb of the loop of Henle,  through the distal convoluted tubule (DCT), and finally to the collecting duct.

As the filtered fluids travel through the different tubes with different functions, the fluids get filtered even more as it reaches the collecting duct.  Starting from where the fluids first get filtered, the bowman’s capsule is responsible for catching the fluids from the glomerulus.

Then the next stop is the PCT. This is where most of the water in the fluid, bicarbonate ions, all of the glucose, amino acids, and most of the sodium, chlorine, and potassion ions are reabsorbed into to the blood capillaries depending on the current status of the body. If the water concentration in the blood capillaries is lower than the water concentration in the PCT, water will get reabsorbed to the blood capillaries through passive transport, which does not require any energy. However, when all of the glucose and amino acids molecules including some of the ions get reabsorbed, it is not through passive transport but rather active transport. This requires energy in the form of ATP which is why the simple cuboidal epithelial cells of the PCT have lots of mitochondria. Since there is a lot of reabsorption that occurs in the PCT, the inner lining of the cells have lots of tiny hair-like extensions called villi. The villi are there to help increase the surface area of which reabsorption can take place. And in the cell membranes of the PCT, there are tiny channels or holes to let the reabsorbed material into the cells so it can eventually reach the blood capillaries. There are two ways in which this happens, but I will explain that towards the end.

Phew!💦That was one long paragraph on such a small part of the nephron! You might want a short break from reading this as there is still a lot to go through!

Okie Dokie, let’s move on!

After travelling through the PCT, the fluids reach the loop of Henle. Since the loop of Henle is always in the shape of a ‘U’, the two parts are called the descending (going down) and ascending(going up) limbs of the loop of Henle. The loop of Henle also has simple epithelial cells like the PCT but it has fewer villi. I’m guessing this is because the loop of Henle has fewer substances it reabsorbs so there is no need for lots of villi. In the descending limb, water again will get reabsorbed depending on the body’s needs, decreasing the water concentration in the fluids. Since the water concentration has decreased in the descending limb, when the fluids reach the ascending limb, there is a higher concentration of sodium, chlorine, potassium, magnesium, and calcium ions in the tubule. This allows the magnesium and calcium ions get reabsorbed through passive transport, while the sodium, chlorine, and potassium ions get reabsorbed through active transport. The methods of which the ions get reabsorbed are different but doing so, the water and ion concentration in the fluids become more neutral.

Once the fluids travel through the loop of Henle, the fluids reach the DCT. The cells of the DCT again have the same type of cells as the other tubules mentioned before but they do not have villi. Once the fluids reach the DCT, there aren’t many substances available to be reabsorbed than hormones and some last minute reabsorption of water. The hormones that are reabsorbed are aldosterone -a steroid hormone, the antidiuretic hormone, and the parathyroid hormone which are both peptide hormones. These are all hormones that are related to water regulation in the body. The reabsorption of hormones will depend on the body’s current status and is a very complicated process so I will write about it when I learn about it!😅

Once the fluids have finished going through the DCT, it’s urine now! Whoop whoop! The freshly made urine travels to the collecting duct where it receives urine from other neighbouring nephrons. Also at this stage, if the body needs even more water, some water can be reabsorbed for the last time before it travels to the renal pyramid, to the major calyxes, and down the ureter, to the bladder.

So that is it for making urine in the nephron! But whoah wait, I’m not done yet! There are still some more to come on the urinary system but since I don’t want to bore you to death, I will finish up on the urinary system on my next post. Not sure when my next post will be since tomorrow is the last day of lectures for me before I will be taking 5days off for the Easter holidays! But I hope you learnt something new from this post and Happy Easter!!🐰🐰

xx

Our Body’s Built-In Filter!

Hello, again internet world!

To start off my revisions for Biology & Human Biology and Organic Chemistry, I will start with revising the information that has been stored in my brain most recently, which would be the Urinary System.

Source: Pinterest

I never knew much about the urinary system or how the kidney’s make urine so the past 2 weeks of lectures on the urinary system were all very new to me. And if I’m being honest here, I am quite unsure of what the kidneys are called in Korean (I’m Korean-American so I should know this🙈). But oh well,  I’ll learn it someday!

So, time to get crackin’ with my hair tied up,  some Jazz playing in the background, windows open for fresh air, got my big glass water bottle out for hydration, and most importantly I have just got back from the toilet having done a wee! The result of my kidney’s properly functioning!😁 (this is the type appreciation you gain when you learn about the human body lol)

Our urinary system has it’s main organ which are the Kidneys; kind of like the principle dancer in a ballet so to say. The main attraction who does the most dancing and gets most of the attention/credit. The rest of the organs are the Ureters, Bladder, and Urethra; in this case the corpse de ballet in a ballet. They don’t have as much of a big role, they’re not as appreciated as the principle dancer, but the ballet certainly would not be complete or functional without the corpse de ballet. And no, the ureter and the urethra are not the same (I didn’t know that either).

So what do these organs do? Since the kidneys have the biggest role in the urinary system, let’s start with the kidneys.

The kidneys are two fist-sized, bean-shaped organs that are near where your lowest ribs are. They also always have a friend, the adrenal glands (will explain this in the future) sitting on top of them. The kidneys have 3 layers of supportive tissue to protect, encase, and anchor them to their surrounding area. These layers are called the fibrous capsule, perineal fat capsule, and the renal fascia.

Source: Unknown

This diagram here is an illustration of the kidney anatomy, also called renal anatomy. You will start to notice that anything “renal” is related to the kidneys. There are about 8 lobes in each kidney, each compromised of the cortex, medulla, renal columns, calyces, and pelvis (no, not the pelvic bone).

As you can see, the cortex is in the outer region of the kidney and it is where ultrafiltration (filtration of blood to urine) occurs. The medulla is located more inwards than the cortex, and it makes up the renal pyramids as you can see in the diagram. The renal pyramids are made up of tons of nephrons (we’ll get to this) which is responsible for the main filtering job of our blood. Calyces are the tubes that collect freshly made urine from the pyramids and the funnel-shaped renal pelvis then sends the urine to the ureter which then eventually collects in our bladder.

Going back to the main organs in the urinary system, the ureters are the tubes connecting the kidneys to the bladder. But fun fact, urine doesn’t just go down through the ureter to the bladder because of gravity, it moves down through a movement called peristalsis which is movement caused from smooth muscles surrounding the ureter that kind of massages the urine down to the bladder in a wave-like contracting movement. It also has valve like folds to prevent urine from backflowing up to the kidneys.

Once the urine goes down the ureter through peristaltic movement, it is collected in the bladder until it is excreted from the body through the urethra. The urethra once again pushes urine out of the body through peristaltic movement.

So this is the very basics of the urinary system. Since the urinary system is very complicated with so much information, I will continue with how filtration happens in the next post.

If you are revising for an exam like me or have just read this from curiosity, either way, I hope this post wasn’t boring and that it was easy to understand my use of words.

Till next time!

xx

Mother’s Day Baking

Recently, it was Mother’s Day here in England where I am currently living in. Since I would not be able to celebrate Mother’s Day with my own mom this year, I wanted to do something nice for my partner James’ wonderful mum and nanny. As I love baking for others, I of course knew I would be baking something for them. I made cream puffs for my mom  last year(which she loved) so I thought it would be safe for me to make those again for James’ mum! But being who I am, I didn’t want to make the same thing for James’ nanny.

I started looking around Pinterest and YouTube to find something special for her. I stumbled upon EverydayFood’s “1 pot french pastry cream “recipe which I thought would be perfect for filling a small tart with the pastry cream and fruit garnished on top. It was also the perfect thing to make because I could use about half of the pastry cream for the tart, and the rest folded in some whipped cream for the filling of the cream puffs! A win win since I didn’t want any leftover cream!

EverydayFood  is a great channel on YouTube that introduces great recipes everyday from Martha Stewart’s test kitchen. The main host of the channel is Sarah Carey who is so bright, funny, honest, and down-to-earth which is great because she has such an up-lifting energy. The recipes she shares are just as great as Sarah herself, that I’ve been subscribed to their channel for about 3-4 years now.

Another star of the EverydayFood channel is Thomas Joseph. He started his show called “Kitchen Conundrums with Thomas Joseph” a few years ago where he shares tips and tricks to kitchen conundrums submitted by the viewers. He’s very organized and has lots of knowledge related to the sciences behind recipes which is great for someone like me who can be a bit of a  skeptic at times.

So I used EverydayFood’s recipes for both the pastry cream and the pastry for the cream puffs. I would’ve made the tart shell for the tart as well but since my tart tin is quite big, I decided to buy a smaller pre-baked tart shell this time.

I wish I took some pictures but everything turned out really well and James’ mum and nanny both enjoyed their baked goods.😊 The recipe videos are down below as I highly recommend you try making them yourselves!

xx

Make No-Fuss Pastry Cream – Kitchen Conundrums with Thomas Joseph

The Perfect Cream Puff – Kitchen Conundrums with Thomas Joseph

Introduction to this Blog

Hi there!

I’m Dain, currently a student at a university in London and a “retired” ballet dancer. I danced most of my life, and because food was such a big part of my life growing up, I am currently studying Human Nutrition to further understand the relationship between food and humans.

I have a huge passion for anything related food such as cooking, baking, healthy eating, nutrition, you name it! I am also a huge lover of plants and enjoy growing plants myself. Especially herbs for cooking! Since I am  a “retired” ballet dancer, I naturally have great interests in sports, different types of workouts and exercises, and still moving my own body as well. And last but not least…. I am a HUGE animal lover! I have a rescue dog named Tory who is currently living with my family in South Korea, whom I miss very much. Rescuing Tory has made a such big impact in my life that I cannot ignore animal/ pet related issues anymore when I hear about them! Although I have not been able to make a big difference myself for the well-being of animals, it is something that I wish to be working for in the future even if it may be a small difference I make.

I am starting this blog to share my love for food by giving you some of my favorite recipes that I’ve created, and also recipe ideas I get from youtubers, bloggers, famous chefs, etc.

This blog will also be used as a tool to help myself revise through material that I have learnt from university in the past school year. I believe trying to teach an idea to someone is a great way to actually learn something which is why I will be sharing the information I receive in the journey through my studies.

And there might be some occasional pictures of my dog Tory being shared in this blog since this blog is named after her.

I am not sure where I am going with starting this blog but we’ll see!

xx