The Urinary System – Selective Reabsorption

Last week, we learned about the general filtration process that occurs in our kidneys. This week, we’ll learn just how our kidneys modify the filtrate to produce urine.

The filtrate that is in the renal tubule consists of water as well as other small molecules, like sugars and urea. Some of these molecules, like sugars, can return to the bloodstream in a ‘process’ known as selective reabsorption. It’s called ‘selective’ reabsorption because the bloodstream is picky as to what it absorbs from the tubule. The molecules that leave the tubule enter tiny blood vessels next to the tubule, which are called peritubular capillaries. The molecules can then be carried through the rest of the circulatory system, to provide our body cells with nutrients (if they’re sugars).

Parts of the Kidney

Selective reabsorption mainly occurs in the proximal tubule, which is the beginning of the tubule. The proximal tubule is just after the Bowman’s capsule. Whenever a molecule leaves, it is accompanies by water, which means a lot of water is reabsorbed by the bloodstream in this process.

By returning the molecules to the bloodstream, the remaining filtrate’s composition changes. As water leaves, the concentration of particles in the tubule increases.

Hormones can affect what is reabsorbed in the distal tubule. These hormones are the anitidiuretic hormone (ADH), which is also known as vasopressin, and aldosterone. They’ll be discussed next week when we talk about Concentration and Dilution!

The Urinary System – Filtration

Last week, we talked about the basics of the urinary system, including the organs involved. This week, let’s take a closer look at what happens in the kidney, starting with filtration. The posts will be segmented because there will be a lot of new terms coming your way, and I would hate for you to get overwhelmed! So let’s learn how our bodies makes our pee, step by step.

Parts of the kidney

The basic functional unit within the kidneys is known as the nephron. This consists of all of the numbered portions, starting at the glomerulus (5) and ending at the distal tubule (6). 

The main components involved in filtration are the arteries, and the glomerulus.

Filtration

It is at the Bowman’s capsule where the filtration of blood occurs. The blood from the renal artery (renal means ‘kidney’) flows into a smaller version of an artery, known as the afferent arteriole. The name sounds weird, but ‘afferent’ basically means ‘towards something’. So this arteriole is moving blood towards the glomerulus. So this arteriole can also be referred to as the afferent glomerular arteriole.

The afferent arteriole then branches to form tiny blood vessels known as capillaries. These capillaries form a ball-like structure, which is part of the glomerulus (5). The capillaries are therefore called the glomerular capillaries.

The blood from the capillaries continues to flow into the next vessel, which is another arteriole, named the efferent arteriole. ‘Efferent’ means ‘away from something’, so the blood is moving away from the glomerulus. So this arteriole can also be referred to as the efferent glomerular arteriole.

This movement of the blood increases the amount of pressure within the capillaries, causing fluids to leak out. These fluids pass through a filter-like membrane, known as the glomerular basement membrane. Some substances are too large to pass through the basement membrane and, therefore, continue to circulate through the bloodstream.

The filtrate that goes through the glomerular basement membrane enters the Bowman’s capsule. The space inside the Bowman’s capsule is continuous with the rest of the tubule, which includes the proximal tubule, the loop of Henle and the distal tubule. The filtrate is concentrated and modified within these components of the tubule, which will be discussed next week.

And that is, thankfully, all there is to the filtration process for the urinary system! Next week, we’ll learn about what happens to the filtrate in the tubule.

The Urinary System – Basics

Before we can talk about how alcohol affects your urinary system, it’s important to understand the urinary system and how it usually works first. This will be a pretty general overview, though I will also provide a molecular overview of the system next week!

So let’s start learning about how urine is made!

The Urine Pathway

The organs involved in your urinary system:

  • Liver – synthesizes urea and releases it into the blood
  • Kidneys – filters the blood for urea, sodium, bicarbonate and water. If they are high levels of any of them, the kidneys will divert them from the bloodstream, and produces urine.
  • Bladder – the products of urine move from the kidney to your bladder, then to the urethra to be released.

The bladder actually has two muscles that control the release of urine: the internal and external sphincter. The internal sphincter relaxes on its own accord, thanks to your sympathetic nervous system. It is the external sphincter that helps you control whether you pee your pants or not.

And those are the basics of the urinary system! Next week, we’ll be looking at the detailed pathway (for you keeners (: ).

Alcohol – Effects on the Body

I’m a university student and you can bet that I’ve seen a lot of people under the influence of alcohol. They can be loud, giggly, emotional, and sometimes really tired.

I wanted to see just what effects alcohol has on our bodies, so posts about the different effects of alcohol will be popping up every now and then. For now, I thought it would be cool to see the list of effects alcohol has been found to have on our bodies.

Some of these effects are real extremes, so take them lightly. 🙂

List of the effects of alcohol on our body

Short-term effects

  • Nausea
  • Diarrhea
  • Makes you urinate more frequently (stay tuned, we’ll be talking about this one shortly!)
  • Flushed appearance
  • Reduced cognitive and motor skills(which is why you shouldn’t drink and drive!)
  • Loss of inhibitions and more confidence
  • Blurred vision (aka beer goggles) and slurred speech
  • Intense moods, e.g. aggression, elation, depression
  • Headache
  • Blackouts
  • Alcohol poisoning, which is really lethal

Diseases/conditions (in extreme cases!!!)

  • Can lead to the development of heart disease after long-term excessive use.
  • Potential cancer developing effects
  • May cause pancreatitis, which can lead to the development of diabetes
  • Liver disease
  • High blood pressure
  • Depression and/or anxiety
  • Weakened immune system
  • Anemia

Effects on our reproductive systems?!

  • Linked to damaging fertility (extreme case)
  • Small amounts of alcohol can affect a woman’s menstrual cycle
  • Alcohol can reduce the amount of testosterone a man produces
  • May affect the quality of a man’s sperm

And this is just a sampling of all of the effects of alcohol. In a couple of weeks, we’ll be talking about urination so that we can get to explore the effects of alcohol on it the week after :).

So, take it easy with eggnog for now, ladies and gents. No need to binge drink, it may just lead to some unhealthy effects!

I will be on hiatus until the first week of January, due to the holidays but Happy holidays and Happy New Year 🙂 Stay safe!

Pins and Needles aka Parasthesia

Nowadays, it seems like my legs get a lot more sleep than I do. “#firstworldproblems, #universitywoes”. But, really, why do our limbs fall asleep and why do they tingle us so uncomfortably when they do?

Pins and Needles

The sleeping of our limbs, also termed ‘parasthesia’, is the result of our nerves acting abnormally due to an increased pressure on them for a prolonged period of time. Our nerves essentially act as little messengers between our limbs and our brain. So this prolonged pressure on the nerves results in the loss of communication between the limbs and our brain.

There is also a prolonged pressure placed on our blood vessels, which results in our nerves not receiving enough oxygen or nutrients.

So, in response to this pressure, nerves, much like how we respond to pressure, can react in to different ways: They can either become unresponsive and wait until the pressure has been removed, or they will essentially begin to spaz out and rapidly send signals in hopes of sending them in the right direction.

Now, the latter causes a problem because we have a lot of different nerves feeding our brains with a lot of different information: some inform us about temperature, some others about pressure on our skin and so forth. So when the nerves start spastically sending signals, the brain is unable to fully interpret what is happening and gets a mix of signals about warmth and numb sensations as well as conflicting signals about being cold and tingling sensations. This is why our sleeping limbs are described as having pins and needles. The mix of signals results in a mix of sensations, including an odd duality of numbness and tingling.

How to wake up your limbs

Many people try to hit their limbs that have fallen asleep. That doesn’t really do anything, unfortunately. The best we can do is to change our positions to remove the pressure and wait for the blood flow and nerve responses to return to normal.

And that’s all there is to know about pins and needles. Ironically, my foot has now fallen asleep so it’s time to practice what I preach.

 

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Prostate Cancer – Risks and Prevention

The end of Movember is upon us, so I thought it would be good to cover a tidbit on the risks and prevention tips in regards to prostate cancer!

Risk Factors for Prostate Cancer

There are four main categories for the risk factors:

  • Age: Men who are over the age of 40 with a family history of prostate cancer and are African Americans, for other men there is an increased risk after the age of 50. 60% of individuals with prostate cancer were found to be over the age of 65.
  • Family History: As mentioned in the point above, family history plays a role in a man’s risks for prostate cancer. Your risk is doubled if any close male blood relative has or had the disease.
  • Race: African Americans have been found to have the highest rate of prostate cancer in the world.
  • Diet: If you’re not eating healthily (i.e. all meat, no vegetables), then your risk for developing prostate cancer increases. High fiber diets with low red meat/fatty foods consumption is recommended as an alternative diet to help lower your risks.

Tips to maintain and monitor your prostate

  • After you reach the age of 40, it is recommended that you get your prostate checked every year. Prostate cancer is a slow growing cancer, so it doesn’t always display symptoms. This is why it is so important to get your prostate checked yearly.
  • Exercising regularly to stay physically active is important in maintaining your health. Also, maintaining a healthy body weight is important as obesity appears to play a role in the development of cancers
  • Watch what you eat! I’m not saying that you need to count how many fries you eat, but make sure to incorporate more vegetables and fiber into your diet and try to stay away from the red meats and fatty foods when you can! Fish is also very helpful. Some studies found that diets that were high in calcium were also linked to the development of cancers, so let’s not take too many calcium supplements (if your doctor recommends you take a calcium supplement, stick to how much they tell you to take).
  • There are also drugs that help stop the conversion of testosterone into another hormone (dihydrotestosterone), which has been found to promote prostate growth. This growth can lead to abnormal growth (in order words, too much growth).

And those are the risks and prevention tips for prostate cancer! Know your body, stay safe and have a great weekend! 🙂

 

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American Cancer Society. 2013. Can cancer be prevented?. Cancer.org. <http://www.cancer.org/cancer/prostatecancer/detailedguide/prostate-cancer-risk-factors> November 28, 2013.

Men’s Health Network. 2005. Risk factors. ProstateHealthGuide.org. <http://www.prostatehealthguide.com/cancer_risk.html> November 28, 2013.

Prostate

When I hear November, I think ‘Movember’. The month of the ‘staches. And just like their moustaches, females are unable to have the type of cancer that the month raises awareness for: prostate cancer. But what is the prostate? What does it do normally? Warning: Children, talk to your parents if you’re reading this. There’s a wee wee on here.

What is the prostate?

The prostate is an organ only found in men. It sits below the bladder and wraps around the urethra (which is a tube that carries urine [and sperm for men] from the bladder to the external environment). It has three lobes: the left, center and right lobes, and is part muscle and part glandular.

Now pick up a walnut. That’s approximately the size of a man’s prostate. That’s pretty small for an organ!

So what does this walnut-sized organ do?

The prostate is important for secreting fluid that is slightly alkaline, which will form part of the seminal fluid. The seminal fluid is the fluid that carries sperm from the urethra to the tip of the penis.

The prostate also helps in male climax (or orgasm). Its muscular portion will help the propelling of sperm and its own secreting fluid into the urethra, where it will then exit.

The Male Reproductive System, including the prostate.

The growth of cells in the prostate is stimulated by the male hormone, testosterone.

And those are the basics of the prostate! Join me next week when we talk more about the prostate.

 

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Blisters

My roommate’s boots were extremely vicious today, causing these alarmingly large blisters to form on the back of her heels. But what allows boots, and other footwear, the right to ruin our days so easily with the formation of blisters? How do they even do it?

Let’s start with the basics: What’s a blister?

A blister is a layer of skin, more specifically one of the epidermis layers, that splits from the other layers of skin, allowing pus to squeeze between them.

Pus is the term used to describe the blood serum (without red blood cells and clotting factors) that usually consists of water, white blood cells, blood proteins in addition to a few other things (it can sometimes have bacteria, gross).

How do blisters form?

Footwear can cause blisters as a result of the friction between the two. This friction leads to the uppermost layers of the epidermis peeling away from some of the other layers, without falling off. This is is normally referred to as a Friction Blister (fitting, right?). Some footwear need to be broken into so that they don’t keep rubbing against your skin too often.

But there are things other than friction that can cause blisters too! These factors are:

  • Heat (sunburns can lead to blisters!)
  • Chemical reactions
  • Medical conditions (like cold sores or the chicken pox)

Don’t burst your bubble

Like most other things the body does, the formation of the blister is actually a good thing. If they remain intact, then the liquid in the blister will be reabsorbed after a new layer of skin has been formed underneath the blister and the old layer of skin will peel away completely.

If you pop the blister, however, it can lead  to the further infection of your skin since the unhealed area has been exposed. The raised layer of skin and the pus act as a protective shield against infections and allows your body to regenerate its new skin in peace.

However, if they hurt too much then you may need to let the pus out using sterile equipment, a sterilized needle or blade. It may hurt a lot when the pus in the blister has infectious particles or intrusive particles. If the pus is white/yellow, then it definitely contained infectious particles (this differs from healthy pus, which would be clear). If your skin around the blister is red or warm for a long time, that’s another sign of infection! If you think your blister is infected, it is best to get medical attention.

For the most part, the blisters are here to help us with our silly needs like uncomfortable (but fancy!) shoes or going out in the sun without sunscreen. They’ve got our backs, for sure, so let’s let them be.

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Risk Factors for Breast Cancer

Last week, we talked about breast cancer and how you can take certain steps to be aware of your breast health.
This week, we’ll look at a list of risk factors that have been linked to the development of breast cancer. By knowing these risk factors ahead of time, we can help in reducing our risk of breast cancer.
Risk factors
Risk factors increase one’s chances of developing breast cancer. Studies that have looked for risk factors look for things that are common in people who develop breast cancer than in others. You should know thought that risk factors don’t always act at the same magnitude, so take this with a grain of salt. Risk factors don’t always lead to the disease, so please don’t create a checklist and start to freak out. It’ll really help no one.
Luckily, some risk factors are modifiable so you do have some control over your health. Others aren’t as easy to hear about, as they might have to do with your genes, or other uncontrollable traits.

Modifiable Risk Factors for Breast Cancer

  • Body weight
  • Physical activity
  • Alcohol use
    • is a known carcinogen (cancer-inducing agent).
    • Depends on how much you drink and how often
  • Smoking
  • Hormone replacement therapy and contraceptives
    • Estrogen and progesterones can sometimes increase our risk of breast cancer
    • Synthetic hormones can also increase this risk
  • Pregnancy and breastfeeding
    • Having gone through pregnancy and breastfeeding can actually lower your risk of getting breast cancer. Now, I’m not saying “Go make babies now!”. But, I mean, babies are cute…
    • Having a child after the age of 35 may bring about a slight increase of risk, much like not having a child at all (This is just for you, ladies. Men, your breasts don’t care if you have kids or not)
  • Radiation exposure

Non- modifiable Risk factors

  • Gender and age
    • Women have a greater risk than men because of those specialized lobules they have.
    • Risk increases as you age
  • History of cancer (family or personal)
  • Early menstruation/late menopause
  • Breast density or conditions
  • BRCA gene mutations

Factors that aren’t risk factors

  • Deodorants or antiperspirants
  • Bras
  • Breast Implants
  • Stress
  • Abortion

Now remember, risk factors don’t always lead to the disease but it’s always good to look after yourself! So take care, know your body and stay healthy 🙂

References

Canadian Breast Cancer Foundation. 2013. Breast Cancer Risk Factors. CBCF.orghttp://www.cbcf.org/central/AboutBreastHealth/PreventionRiskReduction/risk_factors/Pages/default.aspx. November 7, 2013.

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Breast Health

The month of October was Breast Cancer Awareness Month, so naturally I’m talking about Breast Health on the first of November. But since all diseases need year-long awareness, let me carry this one into November.

Who needs to monitor their breast health?

We all have breasts! That’s right, breasts for everyone! The only difference between female and male breasts is that male breasts lack specialized lobules, which are divisions of the breast required to aid in the production and excretion of milk. Apparently, Mother Nature thought men didn’t need to be able to produce milk, but I’m sure there are plenty of mothers out there that would argue otherwise.

Either way, there is only one difference between male and female breasts, which means that both women and men need to continuously monitor their breast health.

Why monitor breast health?

Breast cancer usually originates in the lobules of your breasts, which is probably a super great reason to keep an eye on them. And a scary one.

But I thought men don’t have lobules, so why do they get breast cancer? is probably what you’re thinking. Well, calm down, I’ll explain.

Men don’t have the lobules required to produce milk; they do, however, have lobules. The good ol’, regular lobules that give your breast its mass. So guys, girls, everyone, check your breasts regularly.

How do you do it though?

Here are some tips brought to us by the Canadian Breast Cancer Foundation:

  • Know how your breasts normally look and feel
  • Look and feel for changes, such as
    • Lumps
    • Thickening of the skin
    • Nipple changes and/or discharges
    • Redness of any part of the breast
    • Skin changes (rashes, colour, etc)
    • Dimpling or puckering of the skin or nipple
    • Swelling or pain in the breast area or under arm

Make sure to look and feel at each of these regions:

  • Each whole breast
  • Under and above each breast
  • Under both arms

If you’re ever worried, contact your family physician and set up an appointment. It is always better to be safe.

Next week we’ll look at the established Risk factors for Breast cancer to keep this ball of awareness rolling. Hope your Halloween night was great! Stay safe, lovelies! 🙂

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