Tag Archives: urinary system

The Urinary System

What Does The Urinary System Do?

The urinary system eliminates waste from the body, in the form of urine.

The kidneys remove waste from the blood. The waste combines with water to form urine. From the kidneys, urine travels down two thin tubes called ureters to the bladder. When the bladder is full, urine is discharged through the urethra.

Urinary System

What Makes Up The Urinary System?

Kidneys

A pair of purplish-brown organs located below the ribs toward the middle of the back. Their function is to remove liquid waste from the blood in the form of urine; keep a stable balance of salts and other substances in the blood; and produce erythropoietin, a hormone that aids the formation of red blood cells.

The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.

Ureters

Narrow tubes that carry urine from the kidneys to the bladder. Muscles in the ureter walls continually tighten and relax forcing urine downward, away from the kidneys. If urine backs up, or is allowed to stand still, a kidney infection can develop. About every 10 to 15 seconds, small amounts of urine are emptied into the bladder from the ureters.

Bladder

A triangle-shaped, hollow organ located in the lower abdomen. It is held in place by ligaments that are attached to other organs and the pelvic bones. The bladder’s walls relax and expand to store urine, and contract and flatten to empty urine through the urethra. The typical healthy adult bladder can store up to two cups of urine for two to five hours.

Sphincter muscles

Circular muscles that help keep urine from leaking by closing tightly like a rubber band around the opening of the bladder.

Nerves in the bladder

These alert a person when it is time to urinate, or empty the bladder.

Urethra

The tube that allows urine to pass outside the body. The brain signals the bladder muscles to tighten, which squeezes urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax to let urine exit the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

How Does The Urinary System Work?

Your body takes nutrients from food and uses them to maintain all bodily functions including energy and self-repair. After your body has taken what it needs from the food, waste products are left behind in the blood and in the bowel. The urinary system works with the lungs, skin, and intestines – all of which also excrete wastes – to keep the chemicals and water in your body balanced.

5 Interesting Facts About The Urinary System

  1. Adults pass about a quart and a half of urine each day.

  2. The volume of urine formed at night is about half that formed in the daytime.

  3. Normal urine is sterile. It contains fluids, salts and waste products, but it is free of bacteria, viruses and fungi.

  4. In ancient Egypt and Ireland, women stood to urinate. It was the men who sat or squatted.

  5. Since urine contains large amounts of urea, it is an excellent source of nitrogen for plants and a good accelerator for compost.

Adults eliminate about a quart and a half of urine each day. The amount depends on many factors, especially the amounts of fluid and food a person consumes and how much fluid is lost through sweat and breathing. Certain types of medications can also affect the amount of urine eliminated.

The urinary system removes a type of waste called urea from your blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys.

The kidneys are bean-shaped organs about the size of your fists. They are near the middle of the back, just below the rib cage. The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule. Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.

From the kidneys, urine travels down two thin tubes called ureters to the bladder. The ureters are about 8 to 10 inches long. Muscles in the ureter walls constantly tighten and relax to force urine downward away from the kidneys. If urine is allowed to stand still, or back up, a kidney infection can develop. Small amounts of urine are emptied into the bladder from the ureters about every 10 to 15 seconds.

The bladder is a hollow muscular organ shaped like a balloon. It sits in your pelvis and is held in place by ligaments attached to other organs and the pelvic bones. The bladder stores urine until you are ready to go to the bathroom to empty it. It swells into a round shape when it is full and gets smaller when empty. If the urinary system is healthy, the bladder can hold up to 16 ounces (2 cups) of urine comfortably for 2 to 5 hours.

Circular muscles called sphincters help keep urine from leaking. The sphincter muscles close tightly like a rubber band around the opening of the bladder into the urethra, the tube that allows urine to pass outside the body.

Nerves in the bladder tell you when it is time to urinate, or empty your bladder. As the bladder first fills with urine, you may notice a feeling that you need to urinate. The sensation to urinate becomes stronger as the bladder continues to fill and reaches its limit. At that point, nerves from the bladder send a message to the brain that the bladder is full, and your urge to empty your bladder intensifies.

When you urinate, the brain signals the bladder muscles to tighten, squeezing urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax. As these muscles relax, urine exits the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.

What Can Go Wrong With Your Urinary System?

Problems in the urinary system can be caused by aging, illness, or injury. They range in severity from easy to treat to life threatening. These are examples:

Benign Prostatic Hyperplasia (BPH)

BPH is a condition in men that affects the prostate gland, which is part of the male reproductive system. The prostate is located at the bottom of the bladder and surrounds the urethra. BPH is an enlargement of the prostate gland that can interfere with urinary function in older men. It causes blockage by squeezing the urethra, which can make it difficult to urinate. Men with BPH frequently have other bladder symptoms including an increase in frequency of bladder emptying both during the day and at night. Most men over age 60 have some BPH, but not all have problems with blockage. There are many different treatment options for BPH.

Painful Bladder Syndrome/Interstitial cystitis (PBS/IC)

PBS is a chronic bladder disorder also known as frequency-urgency-dysuria syndrome. In this disorder, the bladder wall can become inflamed and irritated. The inflammation can lead to scarring and stiffening of the bladder, decreased bladder capacity, pinpoint bleeding, and, in rare cases, ulcers in the bladder lining. The cause of IC is unknown at this time.

Kidney Stones

This is the term commonly used to refer to stones, or calculi, in the urinary system. Stones form in the kidneys and may be found anywhere in the urinary system. They vary in size. Some stones cause great pain while others cause very little. The aim of treatment is to remove the stones, prevent infection, and prevent recurrence. Both nonsurgical and surgical treatments are used. Kidney stones affect men more often than women.

Prostatitis

Prostatitis is inflammation of the prostate gland that results in urinary frequency and urgency, burning or painful urination, a condition called dysuria, and pain in the lower back and genital area, among other symptoms. In some cases, prostatitis is caused by bacterial infection and can be treated with antibiotics. But the more common forms of prostatitis are not associated with any known infecting organism. Antibiotics are often ineffective in treating the nonbacterial forms of prostatitis.

Proteinuria

Proteinuria is the presence of abnormal amounts of protein in the urine. Healthy kidneys take wastes out of the blood but leave in protein. Protein in the urine does not cause a problem by itself. But it may be a sign that your kidneys are not working properly.

Renal (Kidney) Failure

Renal Failure results when the kidneys are not able to regulate water and chemicals in the body or remove waste products from your blood. Acute renal failure (ARF) is the sudden onset of kidney failure. This condition can be caused by an accident that injures the kidneys, loss of a lot of blood, or some drugs or poisons. ARF may lead to permanent loss of kidney function. But if the kidneys are not seriously damaged, they may recover. Chronic kidney disease (CKD) is the gradual reduction of kidney function that may lead to permanent kidney failure, or end-stage renal disease (ESRD). You may go several years without knowing you have CKD.

Urinary Tract Infections (UTIs)

UTIs are caused by bacteria in the urinary tract. Women get UTIs more often than men. UTIs are treated with antibiotics. Drinking lots of fluids also helps by flushing out the bacteria.

The name of the UTI depends on its location in the urinary tract. An infection in the bladder is called cystitis. If the infection is in one or both of the kidneys, the infection is called pyelonephritis. This type of UTI can cause serious damage to the kidneys if it is not adequately treated.

Urinary Incontinence

Urinary Incontinence, or loss of bladder control, is the involuntary passage of urine. There are many causes and types of incontinence, and many treatment options. Treatments range from simple exercises to surgery. Women are affected by urinary incontinence more often than men.

Urinary Retention

Urinary Retention, or bladder-emptying problems, is a common urological problem with many possible causes. Normally, urination can be initiated voluntarily and the bladder empties completely. Urinary retention is the abnormal holding of urine in the bladder. Acute urinary retention is the sudden inability to urinate, causing pain and discomfort. Causes can include an obstruction in the urinary system, stress, or neurologic problems. Chronic urinary retention refers to the persistent presence of urine left in the bladder after incomplete emptying. Common causes of chronic urinary retention are bladder muscle failure, nerve damage, or obstructions in the urinary tract. Treatment for urinary retention depends on the cause.

How Do Your Keep Your Urinary System Healthy?

To keep your urinary system healthy, follow these tips . . .

  1. Drink water when you feel thirsty.

    When you urinate, you are eliminating waste products from your system. To keep your urine flowing normally and avoid blockages, be sure to drink when you are thirsty. The American Dietetic Association recommends eight 8oz. glasses per day.

  2. Go easy on the salt, which makes you retain water.

    Too much salt in your diet keeps the salt/mineral/water balance in your kidneys off kilter. A high-sodium diet has been associated with elevated blood pressure. Long-term, uncontrolled high blood pressure can lead to kidney damage. A high-salt diet may also contribute to the development of kidney stones. Paying attention to sodium labels on processed foods and reducing intake of canned soups and vegetables, luncheon meats, hot dogs, and sausages, may help you lower your risk for developing calcium-based kidney stones.

  3. Consider reducing your caffeine intake.

    Drinking caffeinated beverages may irritate your bladder and serve as a diuretic (increase your need to urinate). The more caffeine you drink, the more you may have to urinate.

This article is part of a series called “Your Body: An Owner’s Manual” which explains how your body systems work and how to maintain them. The first article in the series included a picture of my wife, fitness coach Kathie Lamir, who exemplifies a healthy body. Pictures of Kathie were so well received that I have included one with each article in the series

Fitness Authority Kathie Lamir

Your Body: An Owner’s Manual

There was a time when I didn’t know much more about the human body than that my wife’s was beautiful!

Fitness Guru Kathie LamirSee what I mean?

How strange, I thought. We only get one body. It has to last a lifetime. And the better it works, the better we feel. Why wouldn’t we want to know everything about how it works and how to maintain it?

Yet most of us don’t. We know more about the insides of our car than how our body functions.

Maybe that’s because cars come with owner’s manuals, but your body doesn’t.

Well, problem solved.

This article introduces a 12-part series that will explain how your body works. This series is the instruction manual for your body that you never got.

This initial article will briefly describe the 11 human body systems.

Articles about each of the body systems will follow, one a day. Each article will answer these questions . . .

  1. What Does The System Do?

  2. What Makes Up The System?

  3. How Does The System Work?

  4. What Can Go Wrong With The System?

  5. How Do You Keep The System Healthy?

And each article will include “5 Interesting Facts About The System.”

Before starting this discussion of our body systems, however, you must understand that dividing your body into 11 systems for the purpose of studying them does not mean that they are independent systems. Far from it, they are interconnected and dependent on each other.

In fact, some body parts are part of multiple systems. For example, the long bones (like the femur) are not only part of the skeletal system, but they are also part of the circulatory system because they manufacture blood cells. And the ovaries are part of the endocrine system as well as the reproductive system. More about all of this later . . .

These are the 11 main human body systems, presented in alphabetical order.

Circulatory System

The circulatory system is made up of your heart, blood vessels and blood. Your heart pumps oxygen-rich blood from your left ventricle into your biggest artery, the aorta. From there, the aorta branches into smaller arteries, which then branch into even-smaller arteries that travel all over the body. When blood reaches the smallest blood vessels, called capillaries, an exchange occurs. Oxygen, nutrients and hormones are deposited into the cells and waste material from the cells, such as carbon dioxide, is collected for the return trip to the heart.

Veins carry the blood back to the heart where it enters the right atria, passes through the right ventricle and is sent to your lungs where, in capillaries in the lungs, the waste carbon dioxide is deposited and oxygen is picked up. The newly oxygenated blood returns to the heart and, this time, it enters the left atria. From there it goes to the left ventricle and, from there, it is pumped again .

Click here to learn more about your circulatory system.

Digestive System

Your digestive system consists of organs that break down food into the protein, vitamins, minerals, carbohydrates and fats that your body uses for energy and for building and repairing cells and tissues.

Food passes from your mouth down through a muscular tube called the esophagus, and into the stomach, where food continues to be broken down. The partially digested food passes into the small intestines where it is broken down into nutrients which enter the bloodstream through tiny hair-like projections called villi. The liver, the gallbladder and the pancreas produce enzymes and substances that help with digestion in the small intestine.

The last section of the digestive tract is the large intestine, which includes the cecum, colon, and rectum. Indigestible remains of food are eliminated through the anus.

Click here to learn more about your digestive system.

Endocrine System

The endocrine system is made up of a group of glands that produce the body’s long-distance messengers, or hormones. Hormones are chemicals that control body functions such as metabolism, growth, and sexual development. The glands, which include the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pineal body, pancreas, ovaries, and testes, release hormones directly into the bloodstream, which transports the hormones to organs and tissues throughout the body.

Click here to learn more about your endocrine system.

Immune System

The immune system is our body’s defense system against infections and diseases. Organs, tissues, cells, and cell products work together to respond to dangerous organisms (like viruses or bacteria) and substances that may enter the body from the environment.

An anatomic response physically prevents threatening substances from entering your body. Examples of the anatomic system include the mucous membranes and the skin. If substances do get by, the inflammatory response goes on attack.

The inflammatory system works by excreting the invaders from your body. Sneezing, runny noses, and fever are examples of the inflammatory system at work.

When the inflammatory response fails, the immune response goes to work. This is the central part of the immune system and it is made up of white blood cells, which fight infection by gobbling up antigens. About a quarter of white blood cells, called the lymphocytes, migrate to the lymph nodes and produce antibodies which fight disease.

Click here to learn more about your immune system.

Lymphatic System

The lymphatic system has three main purposes. It removes excess fluid and waste products from the spaces between the cells and returns them to the blood stream. It aids the immune system in destroying and removing waste, debris, dead blood cells, pathogens, toxins, and cancer cells. And it also absorbs fats and fat-soluble vitamins from the digestive system and delivers these nutrients to be used by the cells of the body.

Click here to learn more about your lymphatic system.

Muscular System

The muscular system is made up of tissues that work with the skeletal system to control movement of the body. Some muscles—like the ones in your arms and legs—are voluntary, meaning that you decide when to move them. Other muscles, like the ones in your stomach, heart, intestines and other organs, are involuntary. This means that they are controlled automatically by the nervous system and hormones—you often don’t even realize they’re at work.

Muscles also generate heat to help regulate your body’s temperature and maintain your posture.

Click here to learn more about your muscular system.

Nervous System

The nervous system is the control system and the network of communication for your body.

Think of your brain as a central computer that controls all voluntary and involuntary bodily functions.

Your “computer” acts through a network that relays messages back and forth from the brain to different parts of the body.

This “network” consists of the spinal cord and nerves. The spinal cord runs from the brain down through the back to nerves which branch out to every organ and part of your body.

When a message comes into the brain from anywhere in the body, the brain tells the body how to react. For example, if you accidentally touch a hot stove, the nerves in your skin shoot a message of pain to your brain. The brain then sends a message back telling the muscles in your hand to pull away. Fortunately, all of this occurs lightning fast.

Click here to learn more about your nervous system.

Reproductive System

The reproductive system allows humans to produce children. Sperm from the male, which is produced in the testes, fertilizes the female’s egg, or ovum, in the fallopian tube. The fertilized egg travels from the fallopian tube to the uterus, where the fetus develops over a period of nine months.

Click here to learn more about your reproductive system.

Respiratory System

The respiratory system brings air into the body and removes carbon dioxide. It includes the nose, trachea, and lungs.

When you breathe in, air enters your nose or mouth and goes down a long tube called the trachea. The trachea branches into two bronchial tubes, or primary bronchi, which go to the lungs. The primary bronchi branch off into even smaller bronchial tubes, or bronchioles. The bronchioles end in the alveoli, or air sacs. Oxygen follows this path and passes through the walls of the air sacs and blood vessels and enters the blood stream. At the same time, carbon dioxide passes into the lungs and is exhaled.

Click here to learn more about your respiratory system.

Skeletal System

The skeletal system has a number of functions, some obvious and some less so. Of course, it supports your body and gives it structure.

However, in addition, your skeletal system works with the bones to allow movement, protects your internal organs, produces blood (in the bone marrow) and stores minerals such as calcium and phosphorous which it releases into the blood when necessary.

Click here to learn more about your skeletal system.

Urinary System

The urinary system eliminates waste from the body, as urine. The kidneys remove waste from the blood. The waste combines with water to form urine. From the kidneys, urine travels down two thin tubes called ureters to the bladder. When the bladder is full, urine is discharged through the urethra.

Click here to learn more about your urinary system.

Oh . . . if you want to learn more from the world’s greatest personal trainer, my wife Kathie Lamir, this is her website.