I know why I love to pee – the release, the relief and the wave of pleasure that follows a strong, voluminous release of fluid from the body! If I am honest, I even have a little song for moments of exquisite release!
Even babies look blissful when they release that pressure - involuntary as it may be for them!
But why do we love to pee? Why does it feel so satisfying to release and expel that liquid?
To fully understand the why we need to begin by looking at the what and how of our Urinary System. What is supposed to happen, how it is meant to happen and finally what actually happens if things go wrong. Let’s take a dive into the Urinary System together and explore what really makes us want to pee!
At first glance, our urinary system appears pretty basic – two kidneys, two ureters, one bladder and one urethra. However, upon closer inspection we find within each of these structures exist a variety of tissue layers, capsules, corpuscles, tubules, ducts and vessels which perform a bevy of powerful filtration processes for our bodies. And when I say a ‘bevy’ I do mean a BEVY! We rely on our urinary system to protect us from toxins, excesses and deficiencies; it is a principle regulatory system in the body for a wide variety of homeostatic measurements. Don't believe me? Check out how the Urinary System effects various other systems in the body.
BODY HOMEOSTASIS IMPACT
Integumentary
Kidneys convert Vitamin D precursor made in the skin into its active form - CALCITRIOL
Skeletal
Kidneys help to adjust blood levels of CALCIUM and PHOSPHATE
Muscular
Kidneys help to adjust blood CALCIUM LEVELS REQUIRED FOR CONTRACTION
Kidneys expel CREATININE – formed by muscle use/metabolism
Nervous
Kidneys perform GLUCONEOGENESIS to provide glucose for NEURONS especially during periods of fasting or starvation
Endocrine
Kidneys produce the hormones CALCITRIOL and ERYTHROPOIETIN
Lymphatic
Adjustment of water reabsorption affecting the VOLUME OF INTERSTITIAL FLUID and LYMPH – URINE FLUSHES OUT MICROBES
Respiratory
Lungs and Kidneys work together to help adjust pH of bodily fluids
Digestive
CALCITRIOL increases the absorption of CALCIUM in the GIT
Reproductive
In Males – URETHRA IS PASSAGEWAY FOR BOTH SEMEN AND URINE
Cardiovascular
Kidneys can alter BLOOD VOLUME and BLOOD PRESSURE by adjusting water reabsorption through the release of RENIN
Pretty impressive work for two kidneys, two ureters, one bladder and one urethra to pull off each and every minute that the body is alive. And the product of their work is that golden liquid we all love to release - urine!
What is urine?
Perhaps we are beginning to understand why we love to pee! Better pee health equals better overall health! Every time we expel that golden liquid from our urethras – sickness, dis-ease and imbalance are released from our bodies.
When the body is able to produce good urine it is a clear signal that multiple systems are functioning well.
When the body is unable to produce good urine it is a clear signal that sickness resides somewhere in the body.
How do we know if urine is good?
What does good urine contain?
· Water
· Urea
· Uric acid
· Creatinine
· Na, K, Cl, P, S
· Hormones
· Oxalates
· Normal color: light yellow/amber
· Normal odor: bland, not pungent (can smell sweet in diabetics)
· Normal pH: 6
What does good urine NOT contain …
· Amino acids (proteins like albumin)
· Leukocytes
· Erythrocytes
· Nitrites
· Platelets
How is urine formed?
There are three filtration processes in the production of this liquid gold – Glomerular Filtration, Tubular Reabsorption and Tubular Secretion. Just a quick little explanation of each before we move on is in order here. Each step in the process is critical for optimal urine production as well as for maintaining efficient homeostatic controls in the body.
Glomerular Filtration takes places via a tangled, leaky capillary network which has a large surface area to allow for optimal diffusion of substances to take place. This capillary network, which is 50 times leakier than normal capillaries, filters water and small particles from the blood for expulsion from the body. It also has the ability to keep larger particles (like plasma proteins and glucose) from entering the urine and returning those substances to the blood for general circulation. Clever little capillaries!
Blood constituents that get removed from the body via urine include toxins, urea, uric acid, creatinine, mineral salts, water, ketoacids and hormones. Blood constituents that remain in the blood include leukocytes, erythrocytes, platelets and plasma proteins (yup, we definitely want to keep those in our bodies!) Doctors can perform a blood test to determine the body’s Glomerular Filtration Rate (eGFR) which measures the amount of filtrate formed in the kidneys each minute (this is an estimated value). The eGFR is used to determine whether the glomeruli are performing well. An adult male will average about 125ml/min and an adult female averages 105 ml/min … anything over 90 is considered healthy and normal. This rate must be consistent for optimal homeostasis.
Tubular Reabsorption returns substances to the blood and this process takes place in the renal tubules and collecting ducts. Filtration substances like water, amino acids, glucose and electrolytes are reabsorbed into the blood through active and passive transport processes for general circulation throughout the body. The renal tubules are the final inspectors of all things blood related.
Did you know that the kidneys receive about 25% of all cardiac output!? That is a lot of pressure and a lot of filtering to do!
Tubular Secretion receives substances from the blood and expels it through collecting ducts via the urine. Filtration substances like waste products (creatinine, urea, uric acid), drugs (penicillin) and excess ions (H+) are moved through the tubules and into the collecting ducts for final removal.
When working optimally, these three filtration processes can protect and support the body from bone to blood to GIT to skin to, well everywhere! Without our urinary system we would be walking around in a soup of toxins and excesses – gross.
Why does the Urinary System produce urine? What is the purpose of the UT?
Basic Functions of UT and urinary processes
· Excretion of unwanted substances
· Maintenance of water and electrolyte balance
· pH regulation of bodily fluids
· Production of hormones (EPO & Calcitriol)
· Regulation of red blood cell production
· Regulation of blood glucose levels
· Regulation of blood pressure, volume and osmolarity (concentration of a solution) (kidneys can excrete and conserve water to help regulate blood pressure)
Urine is no simple matter!
And here you thought you were just hydrating and removing simple wastes! Oh no my friend, so much more than just liquid expulsion is happening. Let’s take a look now at one of the above functions in a bit more detail. The hormone production processes performed by our urinary system to learn how and why our bones, blood and immunity depend on a healthy UT (Urinary Tract).
Calcitriol
When UV rays hit our skin, a precursor to Vitamin D is synthesized, sent to the liver to create an inactive form of Vitamin D which is then sent to the kidneys. It is the kidneys which process that inactive-D into Calcitriol, which is the active form of Vitamin D and send it off into the blood.
Calcitriol assists in the absorption of calcium from our food in the GIT and helps move that calcium into our blood more efficiently. This increased calcium absorption from food increases bone formation as the calcitriol will stimulate optimal calcium and magnesium uptake from the GIT. Moreover, calcitriol reduces calcium loss in the kidneys and well as loss of PTH (parathyroid hormone), helping to further balance calcium and magnesium levels in the blood. A deficiency in calcitriol can present as Rickets or Osteomalacia – both conditions which present with soft/brittle bones due to a lack of minerals and nutrients reaching the bony matrix. Calcitriol ensure that the kidneys will stop excreting calcium into the urine, keeping it circulating in the blood for use by the body. Nice little hormone to have dancing in our bodies!
Erythropoietin (EPO)
Now this is a powerhouse of a hormone which our kidneys release which stimulates the production of red blood cells in the red bone marrow. Whilst 10% of EPO is produced in the liver, it is the kidneys that really save the day when it comes to our blood health.
When blood filters through the kidneys, it is ‘inspected’ for various substances, one of which is oxygen. If oxygen levels are low in the blood, the kidneys release EPO from the interstitial tissues and into the blood. When it reaches the bone marrow (via blood circulation) EPO stimulates the production of more red blood cells. Remember that it is the red blood cells that carry oxygen through the body so when the body is low on oxygen more red blood cells are created to balance the disparity. This is why renal failure/disease can present as Anemia – a group of blood disorders caused by low oxygen/hemoglobin levels in the red blood cells.
Note of interest? Have you heard about EPO doping in sports? With higher levels of EPO in their blood, athletes can increase the amount of oxygen in their muscles which will enhance endurance and recovery during training.
When it goes wrong. Painfully wrong.
So, what happens when the system is not working optimally? That is what we will explore next, the pathologies of a weakened or compromised urinary system. Maybe after reading about these painful disorders, we will remember to drink more water – and make better pee!
What are some of the signs and symptoms which indicate a problem with the urinary system? What types of tests can be done? Where do we begin?
Signs/Symptoms of Urinary Tract pathologies
1. Frequent and painful urination with urgency; but little urine production
2. Red Urine (blood or beetroot?!?)
3. Pain in the Loin (lower back: kidney)
4. Pain in Suprapubic area (lower abdominal: bladder)
5. High urine volume WITH great thirst (dehydration)
6. Low or no urine volume (Oliguria or Anuria)
7. Pallor (lack of EPO – Anemia) (bags underneath the eyes)
8. Frothy urine (Proteinuria – proteins present in urine)
9. Oedema (albumin present in interstitial tissues) (puffy face, legs)
10. Itchy skin (due to Uremia – poor waste excretion; skin attempts to release toxins)
11. Nausea and vomiting
12. Change in color? Dark? Cloudy? Frothy?
13. Change in odor? Asparagus? Lack of water? Diabetes?
14. Oedema
15. Exhaustion
Urinary Tract Infection (UTI)
These are infections/inflammations found anywhere in the urinary tract. These are microbial infections, of which a full 75% are caused by the E. coli bacteria. UTI’s are more prevalent in women due to a shorter urethra and its proximity to the anus as compared to the male urethra.
Infections can be caused by poor hygiene (wiping habits after a bowel movement), intercourse or catheter (bacteria pushed up into the body) or poor nutrition. A dipstick test (urine strips) will show the presence of leukocytes, erythrocytes and nitrates in the urine.
Cystitis
This is an infection of the bladder and it can be acute or chronic. Once more there is a higher prevalence in women for the reasons stated above but also in older men who may have an enlarged prostate gland.
Cystitis occurs when bacteria travel up the urethra and enters the bladder. An enlarged prostate will obstruct optimal urine flow out of the bladder and as the urine accumulates, bacteria are allowed time and opportunity to make a home and colonize the bladder, this is called Bladder Stasis. Pain from a cystitis infection will be predominantly in the lower abdominal region (the suprapubic region).
Pyelonephritis
This is an infection of the kidneys and it occurs when there is a microbial infection of the
renal pelvis and medulla regions of the kidneys. When bacteria travel up through the urethra, past the bladder, through the ureters and land in the kidneys, infection of the nephrons occurs, filling the with a purulent exudate (pus!). This is a much more serious condition which can lead to Septicemia, Renal Abscess, Renal Fibrosis, Secondary Hypertension and Renal Necrosis. A dipstick test will show similar results as UTI and Cystitis but with Pyelonephritis the strip will also show signs of protein present in the urine. When this happens, further testing is required such as blood tests for CRP/ESR/WBC, imaging with ultrasound and Urine Microscopy to look for casts, bacteria, proteins and blood cells.
Diabetic Nephropathy
(Diabetic Kidney Disease)
This is a common complication of both Type I and Type II diabetes and it occurs due to continuous damage to the blood vessels over time due to excessive glucose levels.
A full 40% of diabetics will develop Diabetic Nephropathy and Renal Failure accounts for about 10% of all diabetic deaths. Diabetes can elevate blood pressure which can lead to Glomerulosclerosis which can then lead to enlarged kidneys due to the increased blood pressure (remember that 25% of cardiac output goes straight to the kidneys!). Other causes of Diabetic Nephropathy include hypertension, obesity and smoking. Generally speaking, there are no initial signs and symptoms – unless you count all the symptoms from the plethora of possible underlying diseases. Once developed, the most notable sign would be the enlarged kidneys (which can be seen with ultrasound imaging) as this differentiates this pathology from other urinary system pathologies.
Renal Calculi (Kidney Stones)
Most kidney stones are formed from Calcium Oxalate and Phosphate, though they can sometimes be formed from uric acid (think Gout) or magnesium. Whilst 2% of the population will form kidney stones, the prevalence is 3:1 of men to women who will be diagnosed. This could be due to a higher prevalence of gout in men than in women. Stones can be stationary (remaining in the kidneys to do their damage) or migratory (causing damage throughout the UT as they travel). Causes include dehydration, hyperglycemia, hyperparathyroidism, Gout and renal anatomical abnormalities. One unique symptom of kidney stones is a radiating pain from the loin (lower back) to the groin region – known as Ureteric Colic. Kidney stones form due to an imbalance of water and minerals in body fluids and this imbalance can lower fluid volume, raising the concentration levels. Higher concentration levels (of say calcium) in the blood and low water levels in the blood can cause calcium to deposit and form stones. And this pathology is painful indeed as the body cannot typically pass any stone over 6mm – often surgery to remove the stones is required.
These are just a few of the pathologies that can take hold in the body when we do not care for our Urinary System. Yikes!
Do not fret, the good news is that with a little care and hydration, our urinary systems can bounce back, regenerate and even selectively reverse some of the damage already done.
Prevent with water – build with knowledge and heal with wisdom.
So the next time you expel urine, perhaps take a moment to be grateful for the hard work undertaken by your Urinary System just to keep you safe, balanced, strong and healthy. Maybe you could consider getting it a little gift to say 'thank you'? Something special, like a tall cool glass of pure, healing water. Cheers!
Learning Together
In this series we explore new knowledge together. Information presented in these articles is not intended to be used as medical advice, rather these writings are an effort to share what I am learning as I journey through life.
Please respectfully share any corrections or additional knowledge about this topic in the comments section below, thank you. Together we will keep learning, growing and creating our lives as we wish them to be.
Be well
Stop.Breathe.Focus.Move.Flow.
This is incredible information. To be quite honest, I think I
“simplified” the urinating process/its purpose. I find this intriguing and I’m looking fo to exploring this more.
Thank you.