13 Urinary System

Learning Objectives

  • Identify the anatomy of the urinary system
  • Describe the main functions of the urinary system
  • Spell the urinary system medical terms and use correct abbreviations
  • Identify the medical specialties associated with the urinary system

Chapter Thirteen: Table of Contents

What is it?

What Can Go Wrong?  – Diseases, Disorders, and Conditions of the Urinary System

How Do We Fix it or Make it Better?

Who Can Help? – Careers

Test Yourself

References, Attributions, and Image Descriptions

Introduction to the Urinary System

Term Word Breakdown Description
micturition
mik-chuhr-rIsh-uhn
mictur/o
desire to urinate

-tion
state of being

The process of releasing urine from the urinary bladder (urinating) Video explanation
nephrology
ni-frAH-luh-jee
-logy
study of

nephr/o
kideny

Nephrology deals with the study of the normal working of the kidneys as well as its diseases. Read more
renal pelvis
rEE-nl pEl-vuhs
-al
pertaining to

ren/o
kidney

The renal pelvis is a large cavity in the center of the kidney that collects the urine before it flows into the ureter. Read more
urinary tract
yUHR-ruh-nair-ee trAk
-ary
pertaining to

ur/o
urine

The urinary tract is the body’s drainage system for producing, storing, and excreting urine. For normal urination to occur, all body parts in the urinary tract need to work together, and in the correct order.

The urinary tract includes two kidneys, two ureters, a bladder, and a urethra.

urology
yu-rAH-luh-jee
-logy
study of

ur/o
urine

The field of medicine that specializes in diagnosing, treating, and managing diseases of the male and female urinary tract. Explanation of the difference between nephrology and urology

The urinary system has roles you may be well aware of. Cleansing the blood and ridding the body of wastes probably come to mind. However, there are additional, equally important functions, played by the system. Take, for example, regulation of pH, a function shared with the lungs and the buffers in the blood. Additionally, the regulation of blood pressure is a role shared with the heart and blood vessels. What about regulating the concentration of solutes in the blood? Did you know that the kidney is important in determining the concentration of red blood cells? Eighty-five percent of the erythropoietin (EPO) produced to stimulate red blood cell production is produced in the kidneys. The kidneys also perform the final synthesis step of vitamin D production, converting calcidiol to calcitriol, the active form of vitamin D. If the kidneys fail, these functions are compromised or lost altogether, with devastating effects on homeostasis.

Urinary System Word Parts

Click on prefixes, combining forms, and suffixes to reveal a list of word parts to memorize for the urinary system.

Introduction to the Urinary System

The urinary system has roles you may be well aware of. Cleansing the blood and ridding the body of wastes probably come to mind. However, there are additional, equally important functions, played by the system. Take, for example, regulation of pH, a function shared with the lungs and the buffers in the blood. Additionally, the regulation of blood pressure is a role shared with the heart and blood vessels. What about regulating the concentration of solutes in the blood? Did you know that the kidney is important in determining the concentration of red blood cells? Eighty-five percent of the erythropoietin (EPO) produced to stimulate red blood cell production is produced in the kidneys. The kidneys also perform the final synthesis step of vitamin D production, converting calcidiol to calcitriol, the active form of vitamin D. If the kidneys fail, these functions are compromised or lost altogether, with devastating effects on homeostasis.

Watch this video:

Media 8.1. Urinary System, Part 1: Crash Course A&P #38 [Online video]. Copyright 2015 by CrashCourse.

Urinary System Medical Terms

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Anatomy (Structures) of the Urinary System

Kidney(s)

The kidneys lie on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall, well protected by muscle, fat, and ribs. They are roughly the size of your fist. The male kidney is typically a bit larger than the female kidney. The kidneys are well vascularized, receiving about twenty-five percent of the cardiac output at rest. Figure 8.1 displays the location of the kidneys.

Diagram of a human torso showing the location of the kidneys within the torso.
Figure 8.1 Kidneys. The kidneys are slightly protected by the ribs and are surrounded by fat for protection (not shown). From Betts, et al., 2013. Licensed under CC BY 4.0.

Did You Know?

The right kidney is smaller than the left. It also sits slightly lower to make room for the liver located on the right side of your body.

Kidneys’ Internal Structure

A frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the medulla (see Figure 8.2). The renal columns are connective tissue extensions that radiate downward from the cortex through the medulla to separate the most characteristic features of the medulla, the renal pyramids and renal papillae. The papillae are bundles of collecting ducts that transport urine made by nephrons to the calyces of the kidney for excretion. The renal columns also serve to divide the kidney into 6–8 lobes and provide a supportive framework for vessels that enter and exit the cortex. The pyramids and renal columns taken together constitute the kidney lobes.

Left kidney diagram. Image description available.
Figure 8.2 Left Kidney. From Betts, et al., 2013. Licensed under CC BY 4.0. [Image description.]

Renal Hilum

The renal hilum is the entry and exit site for structures servicing the kidneys: vessels, nerves, lymphatics, and ureters. The medial-facing hila are tucked into the sweeping convex outline of the cortex. Emerging from the hilum is the renal pelvis, which is formed from the major and minor calyxes in the kidney. The smooth muscle in the renal pelvis funnels urine via peristalsis into the ureter. The renal arteries form directly from the descending aorta, whereas the renal veins return cleansed blood directly to the inferior vena cava. The artery, vein, and renal pelvis are arranged in an anterior-to-posterior order.

Nephrons and Vessels

The renal artery first divides into segmental arteries, followed by further branching to form interlobar arteries that pass through the renal columns to reach the cortex (see Figure 8.3). The interlobar arteries, in turn, branch into arcuate arteries, cortical radiate arteries, and then into afferent arterioles. The afferent arterioles service about 1.3 million nephrons in each kidney.

This figure shows the network of blood vessels and the blood flow in the kidneys.
Figure 8.3 Blood Flow in the Kidney. From Betts, et al., 2013. Licensed under CC BY 4.0.

Nephrons are the “functional units” of the kidney; they cleanse the blood and balance the constituents of the circulation. The afferent arterioles form a tuft of high-pressure capillaries about 200 µm in diameter, the glomerulus. The rest of the nephron consists of a continuous sophisticated tubule whose proximal end surrounds the glomerulus in an intimate embrace—this is Bowman’s capsule. The glomerulus and Bowman’s capsule together form the renal corpuscle. As mentioned earlier, these glomerular capillaries filter the blood based on particle size. After passing through the renal corpuscle, the capillaries form a second arteriole, the efferent arteriole (see Figure 8.4). These will next form a capillary network around the more distal portions of the nephron tubule, the peritubular capillaries and vasa recta, before returning to the venous system. As the glomerular filtrate progresses through the nephron, these capillary networks recover most of the solutes and water, and return them to the circulation. Since a capillary bed (the glomerulus) drains into a vessel that in turn forms a second capillary bed, the definition of a portal system is met. This is the only portal system in which an arteriole is found between the first and second capillary beds. (Portal systems also link the hypothalamus to the anterior pituitary, and the blood vessels of the digestive viscera to the liver.

This image shows the blood vessels and the direction of blood flow in the nephron.
Figure 8.4. Blood Flow in the Nephron. The two capillary beds are clearly shown in this figure. The efferent arteriole is the connecting vessel between the glomerulus and the peritubular capillaries and vasa recta. From Betts, et al., 2013. Licensed under CC BY 4.0.

Ureter(s)

The kidneys and ureters are completely retroperitoneal, and the bladder has a peritoneal covering only over the dome. As urine is formed, it drains into the calyces of the kidney, which merge to form the funnel-shaped renal pelvis in the hilum of each kidney. The hilum narrows to become the ureter of each kidney. As urine passes through the ureter, it does not passively drain into the bladder but rather is propelled by waves of peristalsis. The ureters are approximately 30 cm long. The inner mucosa is lined with transitional epithelium and scattered goblet cells that secrete protective mucus. The muscular layer of the ureter consists of longitudinal and circular smooth muscles that create the peristaltic contractions to move the urine into the bladder without the aid of gravity. Finally, a loose adventitial layer composed of collagen and fat anchors the ureters between the parietal peritoneum and the posterior abdominal wall.

Bladder

The urinary bladder collects urine from both ureters ( see Figure 8.5). The bladder lies anterior to the uterus in females, posterior to the pubic bone and anterior to the rectum. During late pregnancy, its capacity is reduced due to compression by the enlarging uterus, resulting in increased frequency of urination. In males, the anatomy is similar, minus the uterus, and with the addition of the prostate inferior to the bladder. The bladder is partially retroperitoneal (outside the peritoneal cavity) with its peritoneal-covered “dome” projecting into the abdomen when the bladder is distended with urine.

Cross-section of the bladder. Image description available.
Figure 8.5 Bladder. (a) Anterior cross section of the bladder. (b) The detrusor muscle of the bladder (source: monkey tissue) LM × 448. (Micrograph provided by the Regents of the University of Michigan Medical School © 2012). From Betts, et al., 2013. Licensed under CC BY 4.0. [Image description.]

Urethra

The urethra transports urine from the bladder to the outside of the body for disposal. The urethra is the only urologic organ that shows any significant anatomic difference between males and females; all other urine transport structures are identical (see Figure 8.6).

Diagrams of female and male genitalia. Image descriptions available.
Figure 8.6. Female and Male Urethras. The urethra transports urine from the bladder to the outside of the body. This image shows (a) a female urethra and (b) a male urethra. From Betts, et al., 2013. Licensed under CC BY 4.0. [Image description.]

The urethra in both males and females begins inferior and central to the two ureteral openings forming the three points of a triangular-shaped area at the base of the bladder called the trigone (Greek tri- = “triangle” and the root of the word “trigonometry”). The urethra tracks posterior and inferior to the pubic symphysis (see Figure 8.6). In both males and females, the proximal urethra is lined by transitional epithelium, whereas the terminal portion is a nonkeratinized, stratified squamous epithelium. In the male, pseudostratified columnar epithelium lines the urethra between these two cell types. Voiding is regulated by an involuntary autonomic nervous system-controlled internal urinary sphincter, consisting of smooth muscle and voluntary skeletal muscle that forms the external urinary sphincter below it.

Did You Know?

A healthy adult bladder can store up to 455 millilitres of urine for between two to five hours.

Micturition Reflex

Micturition is a less-often used, but proper term for urination or voiding. It results from an interplay of involuntary and voluntary actions by the internal and external urethral sphincters. When bladder volume reaches about 150 mL, an urge to void is sensed but is easily overridden. Voluntary control of urination relies on consciously preventing relaxation of the external urethral sphincter to maintain urinary continence. As the bladder fills, subsequent urges become harder to ignore. Ultimately, voluntary constraint fails with resulting incontinence, which will occur as bladder volume approaches 300 to 400 ml.

  • Normal micturition is a result of stretch receptors in the bladder wall that transmit nerve impulses to the sacral region of the spinal cord to generate a spinal reflex. The resulting parasympathetic neural outflow causes contraction of the detrusor muscle and relaxation of the involuntary internal urethral sphincter.
  • At the same time, the spinal cord inhibits somatic motor neurons, resulting in the relaxation of the skeletal muscle of the external urethral sphincter.
  • The micturition reflex is active in infants but with maturity, children learn to override the reflex by asserting external sphincter control, thereby delaying voiding (potty training). This reflex may be preserved even in the face of spinal cord injury that results in paraplegia or quadriplegia. However, relaxation of the external sphincter may not be possible in all cases, and therefore, periodic catheterization may be necessary for bladder emptying.

Nerves involved in the control of urination include the hypogastric, pelvic, and pudendal. Voluntary micturition requires an intact spinal cord and functional pudendal nerve arising from the sacral micturition center. Since the external urinary sphincter is voluntary skeletal muscle, actions by cholinergic neurons maintain contraction (and thereby continence) during filling of the bladder. At the same time, sympathetic nervous activity via the hypogastric nerves suppresses contraction of the detrusor muscle. With further bladder stretch, afferent signals traveling over sacral pelvic nerves activate parasympathetic neurons. This activates efferent neurons to release acetylcholine at the neuromuscular junctions, producing detrusor contraction and bladder emptying.

Concept Check

  • Describe two organs or structures essential to the urinary system.
  • Identify the structure within the kidneys which filters blood.
  • Name a commonly used term for the micturition reflex.

Anatomy Labeling Activity

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Physiology (Function) of the Urinary System

  • Remove waste products and medicines from the body
  • Balance the body’s fluids
  • Balance a variety of electrolytes
  • Release hormones to control blood pressure
  • Release a hormone to control red blood cell production
  • Help with bone health by controlling calcium and phosphorus

Having reviewed the anatomy of the urinary system now is the time to focus on physiology. You will discover that different parts of the nephron utilize specific processes to produce urine: filtration, reabsorption, and secretion. You will learn how each of these processes works and where they occur along the nephron and collecting ducts. The physiologic goal is to modify the composition of the plasma and, in doing so, produce the waste product urine.

Nephrons: The Functional Unit

Nephrons take a simple filtrate of the blood and modify it into urine. Many changes take place in the different parts of the nephron before urine is created for disposal. The term “forming urine” will be used hereafter to describe the filtrate as it is modified into true urine. The principal task of the nephron population is to balance the plasma to homeostatic set points and excrete potential toxins in the urine. They do this by accomplishing three principle functions—filtration, reabsorption, and secretion. They also have additional secondary functions that exert control in three areas: blood pressure (via the production of renin), red blood cell production (via the hormone EPO), and calcium absorption (via the conversion of calcidiol into calcitriol, the active form of vitamin D).

Loop of Henle

The descending and ascending portions of the loop of Henle (sometimes referred to as the nephron loop) are, of course, just continuations of the same tubule. They run adjacent and parallel to each other after having made a hairpin turn at the deepest point of their descent. The descending loop of Henle consists of an initial short, thick portion and long, thin portion, whereas the ascending loop consists of an initial short, thin portion followed by a long, thick portion. The descending and ascending thin portions consist of simple squamous epithelium. Different portions of the loop have different permeabilities for solutes and water.

Collecting Ducts

The collecting ducts are continuous with the nephron but are not technically part of it. In fact, each duct collects filtrate from several nephrons for final modification. Collecting ducts merge as they descend deeper in the medulla to form about 30 terminal ducts, which empty at a papilla.

Glomerular Filtration Rate (GFR)

The volume of filtrate formed by both kidneys per minute is termed the glomerular filtration rate (GFR). The heart pumps about 5 L blood per min under resting conditions. Approximately 20 percent or one liter enters the kidneys to be filtered. On average, this liter results in the production of about 125 mL/min filtrate produced in men (range of 90 to 140 mL/min) and 105 mL/min filtrate produced in women (range of 80 to 125 mL/min). This amount equates to a volume of about 180 L/day in men and 150 L/day in women. Ninety-nine percent of this filtrate is returned to the circulation by reabsorption so that only about 1–2 liters of urine are produced per day.

GFR is influenced by the hydrostatic pressure and colloid osmotic pressure on either side of the capillary membrane of the glomerulus. Recall that filtration occurs as pressure forces fluid and solutes through a semipermeable barrier with the solute movement constrained by particle size. Hydrostatic pressure is the pressure produced by a fluid against a surface. If you have fluid on both sides of a barrier, both fluids exert pressure in opposing directions. The net fluid movement will be in the direction of the lower pressure. Osmosis is the movement of solvent (water) across a membrane that is impermeable to a solute in the solution. This creates osmotic pressure which will exist until the solute concentration is the same on both sides of a semipermeable membrane. As long as the concentration differs, water will move. Glomerular filtration occurs when glomerular hydrostatic pressure exceeds the luminal hydrostatic pressure of Bowman’s capsule. There is also an opposing force, the osmotic pressure, which is typically higher in the glomerular capillary. To understand why this is so, look more closely at the microenvironment on either side of the filtration membrane.

You will find osmotic pressure exerted by the solutes inside the lumen of the capillary as well as inside of Bowman’s capsule. Since the filtration membrane limits the size of particles crossing the membrane, the osmotic pressure inside the glomerular capillary is higher than the osmotic pressure in Bowman’s capsule. Recall that cells and the medium-to-large proteins cannot pass between the podocyte processes or through the fenestrations of the capillary endothelial cells. This means that red and white blood cells, platelets, albumins, and other proteins too large to pass through the filter remain in the capillary, creating an average colloid osmotic pressure of 30 mm Hg within the capillary. The absence of proteins in Bowman’s space (the lumen within Bowman’s capsule) results in an osmotic pressure near zero. Thus, the only pressure moving fluid across the capillary wall into the lumen of Bowman’s space is hydrostatic pressure. Hydrostatic (fluid) pressure is sufficient to push water through the membrane despite the osmotic pressure working against it. The sum of all of the influences, both osmotic and hydrostatic, results in a net filtration pressure (NFP) of about 10 mm Hg (see Figure 8.7).

Net filtration pressure calculation. Image description available.
Figure 8.7 Net Filtration Pressure. The NFP is the sum of osmotic and hydrostatic pressures. From Betts, et al., 2013. Licensed under CC BY 4.0. [Image description.]

A proper concentration of solutes in the blood is important in maintaining osmotic pressure both in the glomerulus and systemically. There are disorders in which too much protein passes through the filtration slits into the kidney filtrate. This excess protein in the filtrate leads to a deficiency of circulating plasma proteins. In turn, the presence of protein in the urine increases its osmolarity; this holds more water in the filtrate and results in an increase in urine volume. Because there is less circulating protein, principally albumin, the osmotic pressure of the blood falls. Less osmotic pressure pulling water into the capillaries tips the balance towards hydrostatic pressure, which tends to push it out of the capillaries. The net effect is that water is lost from the circulation to interstitial tissues and cells. This “plumps up” the tissues and cells, a condition termed systemic edema.

Reabsorption and Secretion

The renal corpuscle filters the blood to create a filtrate that differs from blood mainly in the absence of cells and large proteins. From this point to the ends of the collecting ducts, the filtrate or forming urine is undergoing modification through secretion and reabsorption before true urine is produced. Here, some substances are reabsorbed, whereas others are secreted. Note the use of the term “reabsorbed.” All of these substances were “absorbed” in the digestive tract—99 percent of the water and most of the solutes filtered by the nephron must be reabsorbed. Water and substances that are reabsorbed are returned to the circulation by the peritubular and vasa recta capillaries.

It is vital that the flow of blood through the kidney is at a suitable rate to allow for filtration. This rate determines how much solute is retained or discarded, how much water is retained or discarded, and ultimately, the osmolarity of blood and the blood pressure of the body.

Urinalysis

Urinalysis (urine analysis) often provides clues to renal disease. Normally, only traces of protein are found in urine, and when higher amounts are found, damage to the glomeruli is the likely basis. Unusually large quantities of urine may point to diseases like diabetes mellitus or hypothalamic tumors that cause diabetes insipidus. The color of urine is determined mostly by the breakdown products of red blood cell destruction (see Figure 8.8). The “heme” of hemoglobin is converted by the liver into water-soluble forms that can be excreted into the bile and indirectly into the urine. This yellow pigment is urochrome. Urine color may also be affected by certain foods like beets, berries, and fava beans. A kidney stone or a cancer of the urinary system may produce sufficient bleeding to manifest as pink or even bright red urine. Diseases of the liver or obstructions of bile drainage from the liver impart a dark “tea” or “cola” hue to the urine. Dehydration produces darker, concentrated urine that may also possess the slight odor of ammonia. Most of the ammonia produced from protein breakdown is converted into urea by the liver, so ammonia is rarely detected in fresh urine. The strong ammonia odor you may detect in bathrooms or alleys is due to the breakdown of urea into ammonia by bacteria in the environment. About one in five people detect a distinctive odor in their urine after consuming asparagus; other foods such as onions, garlic, and fish can impart their own aromas! These food-caused odors are harmless.

Hydration chart. Image description available.
Figure 8.8 Urine Color. From Betts, et al., 2013. Licensed under CC BY 4.0. [Image description.]

Urine volume varies considerably. The normal range is one to two liters per day.  The kidneys must produce a minimum urine volume of about 500 mL/day to rid the body of wastes. Output below this level may be caused by severe dehydration or renal disease and is termed oliguria. The virtual absence of urine production is termed anuria. Excessive urine production is polyuria, which may be due to diabetes mellitus or diabetes insipidus. In diabetes mellitus, blood glucose levels exceed the number of available sodium-glucose transporters in the kidney, and glucose appears in the urine. The osmotic nature of glucose attracts water, leading to its loss in the urine. In the case of diabetes insipidus, insufficient pituitary antidiuretic hormone (ADH) release or insufficient numbers of ADH receptors in the collecting ducts means that too few water channels are inserted into the cell membranes that line the collecting ducts of the kidney. Insufficient numbers of water channels (aquaporins) reduce water absorption, resulting in high volumes of very dilute urine.

Concept Check

  • Contrast the following terms: oliguria, anuria and polyuria. What are the differences between these terms as they describe urinary output?
  • Explain how urine colour varies based on food consumed and/or hydration levels.

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Diseases, Disorders, and Conditions of the Urinary System

Term Word Breakdown Description
Urinary tract infection
UHR-ruh-nair-ee trAkt in-fEk-shuhn
-ary
pertaining to

urin/o
urine

UTIs are common infections that happen when bacteria, often from the skin or rectum, enter the urethra, and infect the urinary tract. The infections can affect several parts of the urinary tract, but the most common type is a bladder infection (cystitis).Read more

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Diseases, Disorders, and Conditions of the Kidney

Term Word Breakdown Description
calculogenesis -esis
state or condition

calcul/o
small pebble; stone

gen/o
to produce

The process of forming stones
calculus
kAl-kyuh-luhs
-us
noun ending denoting a structure

calcul/o
small pebble

Kidney stone
hydronephrosis -osis
condition, usually abnormal

hydr/o- fluid; water

nephr/o-
kidney; nephron

Enlargement of the kidney due to a backup of urine
nephrolithiasis -esis
state or condition

lith/o
stone

gen/o- arising from; produced by

Process of forming stones
lithogenesis -esis
state or condition

lith/o
stone

gen/o- arising from; produced by

Process of forming stones
nephrolithiasis -iasis
abnormal condition

nephr/o-
kidney; nephron

lith/o-
stone

Having kidney stones in the urinary system
nephropathy
ni-frAH-puh-thee
pathy
di-sease

nephr/o-
kidney; nephron

Any disease of the kidney
nephroptosis -ptosis
falling, drooping

nephr/o-
kidney; nephron

Abnormally low or drooping of a kidney
polycystic kidney disease
pah-lee-sIs-tik
kId-nee
di-zEEz
-ic
pertaining to

poly-
many, excessive

cyst/o
bladder; cyst; sac of fluid

A genetic disorder that causes many fluid-filled cysts to grow in your kidneys. Read more
pyelonephritis
pie-loh-ni-frIE-tuhs
-itis
inflammation

pyel/o-
pelvis

nephr/o- kidney; nephron

Inflammation and infection of the kidney caused by bacteria
renal failure
rEE-nl AY-lyuhr
The inability of the kidneys to filter waste from the blood properly Read more
acute renal failure (ARF)
uh-kyOOt rEE-nl fAY-lyuh
Occurs when the kidneys suddenly stop filtering waste products from the blood. Read more
chronic renal failure (CRF)
krAH-nik rEE-nl fAY-lyuhr
Kidney failure that comes on slowly. May not have symptoms at the beginning. Read more
end-stage renal disease (ESRD)
End-stayj rEE-nl di-zEEz
When you have permanent kidney failure that requires a regular course of dialysis or a kidney transplant
uremia
yu-rEE-mee-uh
-emia
blood condition

ur/o
urine

Urine in the blood
Occurs when the kidneys can't filter out waste. The waste products back up into the blood. . Read more

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Diseases, Disorders, and Conditions of the Bladder

Term Word Breakdown Description
cystitis
si-stIE-tuhs
-itis
inflammation

cyst/o
bladder; cyst; sac of fluid

Urinary tract infection that originates in the bladder (bladder infection)
cystocele
SIS-tuh-seel
-cele
bulge; henrnia

cyst/o
bladder; cyst; sac of fluid

A collapsed bladder.
The ligaments and muscles that hold the bladder in place stretch or weaken causing the bladder to sag.
Read more
incontinence
in-kAHn-tuh-nuhns
Uncontrolled leaking of urine or defecation. Read more
paruresis uresis
urination

par-
abnormal

Trouble urinating when other people are around. Also known as shy bladder syndrome. Read more

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Diseases, Disorders, and Conditions of the Urethra

Term Word Breakdown Description
epispadias -spadia
to tear; cut

epi-
Upon, outside of

Congenital (born with) abnormal opening of the “meatus” - the hole that urine comes out of). In boys with epispadias, the urethra opens in top of the penis rather than the tip. The space between this opening and tip of the penis appears like an open book (gutter). In girls with epispadias, the urethral opening is towards the clitoris or even belly area. Read more
hypospadias
hie-puh-spAY-dee-uhs
-spadia
to tear; cut

hypo-
under, deficient

A conditional where the opening of the urethra (“meatus” - the hole that urine
comes out of) is on the underside of the penis rather than
the tip of the penis (“distal” position). Read more
urethritis
yur-i-thrIE-tuhs
-itis
inflammation

urethr/o
urethrea

Inflammation of the urethra. Urethritis is commonly due to infection by bacteria, most often through sexual contact. It can typically be cured with antibiotics. Read more

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General Symptoms of Urinary Conditions

Term Word Breakdown Description
anuria
uh-nyUR-ee-uh
-ia
condition

an-
without; lacking

ur/o
urine

Lack of urine production
bacteriuria
bak-tir-ee-yUR-ee-uh
-ia
condition

bacteri/o
bacteria

ur/o
urine

The presence of bacteria in the urine
Read more
dysuria
dis-yUR-ee-uh
-ia
condition

dys-
difficult, abnormal bad: painful

ur/o
urine

Any discomfort associated with urination Read more
enuresis
en-yu-rEE-suhs
ur/o
urine

Bed-wetting
glycosuria
glie-koh-shUR-ee-uh
-ia
condition

glycos/o
sugar

ur/o
urine

When excess blood sugar (glucose) is passed into the urine. Read more
hematuria
hee-muh-tUR-ee-uh
-ia
condition

hemat/o
blood

ur/o
urine

Blood in the urine
nocturia
naw-ct-UR-ee-uh
-ia
condition

noct/o

ur/o
urine

Having to urinate more than once during the night. Read more
oliguria
all-ig0UR-ee-uh
-ia
condition

olig/o
few, little

ur/o
urine

Low urine output. Read more
polyuria
pah-lee-yUR-ee-uh
-ia
condition

poly-
many, excessive

ur/o
urine

When your body makes too much urine.
pyuria
pie-yUR-ee-uh
-ia
condition

py/o
pus

ur/o
urine

Pus in the urine. Comes for an infection. Can smell foul. Read more

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Diabetic Nephropathy

Diabetic nephropathy impacts the kidneys as a result of having diabetes mellitus type 1 or 2.  Higher levels of blood sugar can lead to high blood pressure and this additional pressure exerted on the kidneys causes destruction of the small filtering structures within the kidney. (Mayo Clinic Staff, 2019). To learn more about diabetic nephropathy visit the Mayo Clinic’s Diabetic Nephropathy web page.

Glomerulonephritis

Glomerulonephritis refers to acute or chronic nephritis that involves inflammation of the capillaries of the renal glomeruli. It has various causes, and is noted especially by blood or protein in the urine and by edema. If untreated, it could lead to kidney failure.

Hydronephrosis

Hydronephrosis is a condition whereby the kidneys begin to swell because of the retention of urine. Several conditions can cause hydronephrosis, such as a kidney stone or blood clot. Treatment will vary, depending on the cause (Cleveland Clinic, 2019). To learn more about hydronephrosis the Cleveland Clinic’s web page on hydronephrosis.

Polycystic Kidney Disease

Polycystic kidney disease (PKD) is a genetic disease where cysts grow inside the kidneys. The kidneys enlarge from the cystic collections and damage to the filtering structures of the kidneys can occur. As the disease progresses it may lead to chronic kidney disease (American Kidney Fund, 2020).  To learn more, visit the Kidney Fund’s PKD web page.

Renal Cell Carcinoma

Renal cell carcinoma is a cancer occurring in the kidney tubes where urine is produced or collected. This one of the most common cancers found within the kidneys. Removal of the cancerous lesions is the typical approach from a treatment perspective (Innovation for Patient Care, 2018). To learn more, visit Innovation for Patient Care’s web page on renal cell carcinoma.

Renal Failure

Renal failure occurs when kidneys suddenly or gradually become unable to filter waste products from blood. When kidneys stop filtering, high level of wastes may build. Two types exist acute kidney failure and chronic kidney failure (Mayo Clinic Staff, 2019a). To learn more about kidney failure visit the Mayo Clinic’s page on Chronic Kidney Failure.

Cystitis

Cystitis is inflammation of the urinary bladder, often caused by an infection. A chronic form of this condition is known as interstitial cystitis. Symptoms of cystitis include bladder pressure, voiding frequently, and pain (Mayo Clinic Staff, 2019b). To learn more about cystitis visit the Mayo Clinic’s page on Interstitial Cystitis.

Urinary Tract Infection

A urinary tract infection (UTI) is an infection caused by bacteria, or sometimes, fungi. The exact type of bacterial growth is determined by conducting urine for culture and sensitivity (C&S) testing. In rare cases a UTI may be caused by a virus (Lights & Boskey, 2019). For more information, visit Healthline’s web page on Urinary Tract Infections.

Urinary Incontinence

Urinary incontinence is a loss of bladder control. Those afflicted with the condition will experience urine leakage from the bladder. Weak bladder muscles are a risk factor for developing this condition (Kim & O’Connell, 2017). To learn more about this condition visit Healthline’s webpage Urologic Diseases.

Diagnostic Procedures

Term Word Breakdown Description
blood urea nitrogen (BUN)
blUHd yu-rEE-uh nIE-truh-juhn
A blood test that measures blood urea and nitrogen.

Urea nitrogen is a waste product that kidneys remove from your blood. A high BUN level is a sign that the kidneys are not working well.
Medline Plus

culture and sensitivity (C&S)
UHl-chuhr uhnd sen-suh-tIv-uh-tee
A culture is a tissue sample that is tested in a lab to see what microorganisms (germs) grow in it. The germs are then tested to determine what antibiotic or medications will be most effective in treating it (Courtesy of the National Library of Medicine
cystometry -metry
measurement of

cyst/o
bladder; cyst; sac of fluid

A test used to measure the filling and emptying of the bladder and how much urine the bladder can hold. It also measures the pressure inside the bladder and how full it is when you have the urge to go. American Urological Foundation
Intravenous pyelography (IVP)
in-truh-vEE-nuhs
-ous
pertaining to

intra-
within

ven/o
vein

-graphy
process of recording

pyel/o
pelvis

X Rays of the urinary tract. Dye is injected in to the vein using an IV line, The dye travels in the blood to the kidneys which filters it out. Courtesy of the National Library of Medicine Video explanation of IVP
kidneys, ureters, bladder x-ray (KUB)
kId-neez yUR-uh-tuhrz blAd-uhr Eks-ray
X-Ray of the kidneys ureter and bladder. No contrast material is used.
Medline Plus
retrograde pyelogram -gram
record or picture

pyel/o
pelvis

retro-
backward

A test completed to find out if a kidney stone or other blockage is interfering with the follow of urinary tract. Contrast dye is injected into the ureters. The test is like an intravenous pyelogram, but the with IVP, the dye is injected into a vein rather than injected into the ureter. American Urological Association
urinalysis (UA)
yuhr-ruh-nAl-uh-suhs
A urine test. It is often done to check for a urinary tract infections, kidney problems, or diabetes. Read more
urography -graphy
process of recording

ur/o
urine

An examination used to evaluate the kidneys, ureters and bladder. An IVP is a type of urography. Other types are Computed tomography (CT scans) and magnetic resonance imaging (MRIs) Radiologyinfo.org
ultrasonography -graphy
process of recording
The process of conducting an ultrasound, which is a procedure that takes pictures using sound.Read more
voiding cystourethrography
vOI-ding
-graphy
process of recording

cyst/o
bladder; cyst; sac of fluid

urethr/o
urethra

Test that shows the size of the bladder and how well it can drain. The test is called voiding because x-rays are taken while you pass urine into a container. Read more

Urinalysis

A urinalysis is microscopic group of urine testing. This test detects and measures several substances in the urine such as  products of normal and abnormal metabolism and bacteria (Lab Tests Online, 2020). To learn more about urinalysis visit Lab Tests Online’s Urinalysis web page.

Urine for C&S

Urine for culture and sensitivity. Urine produced by the kidneys is analyzed by way of a urine culture test which can detect and identify bacteria in the urine, which may be causing a urinary tract infection (UTI). If harmful bacteria is found a sensitivity report is generated.  This report lists antibiotics sensitive in the treatment of the bacteria present (Lab Tests Online, 2020a). To learn more about Urine for C&S, visit Lab Tests Online’s Urine Culture web page.

24 Hour Urine Collection

This is a test whereby all urinary output is collected over a 24-hour period of time. The analysis of urinary output over this extended period of time provides a greater indication of normal or abnormal kidney function (Lab Tests Online, 2017). To learn more a, visit Lab Tests Online’s 24-hour Urine Sample article.

CT Scan of Kidney

Computed tomography is a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce a variety of images. It provides detailed images of the kidney looking for disease, cancer, obstructions and other kidney conditions (Johns Hopkins Medicine, n.d.) . To learn more about a CT scan of the kidney visit

Intravenous Pyelogram

An intravenous pyelogram (IVP) is a specialized x-ray designed to produce views of the entire urinary tract. A dye is used to secure the enhanced imaging. The x-rays can also show how well the urinary tract is functioning and any identify any blockages (Canadian Cancer Society, 2020a). To learn more about IVP visit the Canadian Cancer Society’s IVP web page.

Kidney Scan

A kidney scan is an imaging test which views the kidneys. It is considered a nuclear imaging test as it uses radioactive tracers to pick up hot or cold spots within the kidney. These variation are are considered abnormal.

Johns Hopkins Medicine’s page on Computed Tomography (CT or CAT) Scan of the Kidney.

Medical and Surgical Procedures

Term Word Breakdown Description
catheterization
kath-uh-tuhr-ruh-zAY-shuhn
A tube placed in the body to drain and collect urine from the bladder. Read more on Medline Plus
cystectomy
sIs-tEk-tuh-mee
-ectomy
surgical removal

cyst/o
bladder; cyst; sac of fluid

Surgical removal of all or part of the bladder.
cystoscopy
si-stAH-skuh-pee
process of visually examining

cyst/o
bladder; cyst; sac of fluid

Procedure that allows a visual inspection of the bladder and and urethra Read more on Medline Plus
cystoscope
sIs-tuh-skohp
-scope
instrument for examination

cyst/o
bladder; cyst; sac of fluid

A tube with a small camera on the end. Used during cystoscopy. Read more on Medline Plus
hemodialysis
hee-moh-die-Al-uh-suhs
-lysis
break down, destruction, dissolving

hem/o
blood

dia-
across, through

Hemodialysis is a treatment to filter wastes and water from the blood when the kidneys are not functioning normally, Hemodialysis helps control blood pressure and balance important minerals, such as potassium, sodium, and calcium, in the blood. Hemodialysis is a treatment to filter wastes and water from your blood, as your kidneys did when they were healthy. Hemodialysis helps control blood pressure and balance important minerals, such as potassium, sodium, and calcium, in your blood.
lithotripsy
lIth-uh-trip-see
-tripsy
crushing

lith/o
stone

A medical procedure that uses high frequency sound (shock) waves or a laser to break up stones in your kidney, bladder, or ureter. Read more on Medline Plus
nephrectomy
ni-frEk-tuh-mee
-ectomy
surgical removal

nephro/o
kidney; nephron

To remove all or part of a kidney. Read more on Medline Plus
nephrolithotomy -otomy
to cut into

nephro/o
kidney; nephron

lith/o
stone

Surgical removal of a kidney stone. Read more at the National Kidney Foundation
nephropexy -pexy
surgical fixation

nephro/o
kidney; nephron

Surgical fixation of a floating kidney
urethroplasty -plasty
surgical repair

urethr/o
urethra

Surgical repair of the urethra

Cystoscopy

A cystoscopy is a  procedure allowing a physician to check for bladder or ureteral problems, such as bladder cancer.  An endoscope, also known as a cystoscope, containing a camera at the end of it is used (Canadian Cancer Society, 2020). To learn more about cystoscopy visit the Canadian Cancer Society’s Cystoscopy and Ureteroscopy web page .

Dialysis

Dialysis is a treatment that removes waste products from the blood when the kidneys are not fully functioning. This type of therapy is available at home or in a hospital or clinic and there are two main types: peritoneal dialysis and hemodialysis (Kidney Foundation, 2020). To learn more about dialysis visit the Kidney Foundation’s Dialysis web page.

Kidney Transplant

When kidneys fail or when a person is in end stage chronic kidney disease, a surgical procedure is performed in the form of a kidney transplant. This procedure involves harvesting a donor kidney which is transplanted into the recipient in need of a functioning kidney to support vital function of the urinary system.

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Drug Categories

Term Word Breakdown Description
diuretic
die-uhr-rEt-ik
-etic
pertaining to

dia-
across through
(The "a" is deleted)

ur/o
urine

Drugs that stimulate the production of urine

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Medical Specialties and Procedures Related to the Urinary System

Term Word Breakdown Description
nephrologist -ist
specialist

nephr/o
kidney

log/o
study of

A physician who studies and treats conditions of the kidneys
urologist
yu-rAH-luh-jist
-ist
specialist

ur/o
urine

log/o
study of

A physician who studies and treats conditions of the urinary tract

Urology is specialty that “addresses the medical and surgical treatment of disorders and diseases of the female urinary tract and the male urogenital system” (Canadian Medical Association, 2018). This specialty focuses on diagnosis, treatment, and surgical repair. Common clinical visits involve kidney stones, kidney failure and bladder dysfunction. To learn more about urology as a specialty visit the Urology Profile (PDF file) authored by the Canadian Medical Association.

Urologist

A urologist is a medical specialist involved in the diagnosis and treatment of urinary and male genitourinary system conditions, disorders, and diseases such as prostate disease, renal and bladder dysfunctions, and others (Canadian Medical Association, 2018).

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References

American Kidney Fund. (2020, June 17). Polycystic kidney disease. https://www.kidneyfund.org/kidney-disease/other-kidney-conditions/polycystic-kidney-disease.html

Canadian Medical Association. (2018, August). Urology profile. Canadian Medical Association Speciatly Profiles. https://www.cma.ca/sites/default/files/2019-01/urology-e.pdf

Canadian Cancer Society. (2020). Cystoscopy and ureteroscopy. Canadian Cancer Society: Cancer Information. https://www.cancer.ca/en/cancer-information/diagnosis-and-treatment/tests-and-procedures/cystoscopy/?region=on

Canadian Cancer Society. (2020a). Intravenous pyelogram. Canadian Cancer Society: Cancer Information. https://www.cancer.ca/en/cancer-information/diagnosis-and-treatment/tests-and-procedures/intravenous-pyelogram/?region=on

Cleveland Clinic. (2019, May 22). Hydronephrosis. https://my.clevelandclinic.org/health/diseases/15417-hydronephrosis

[CrashCourse]. (2015, October 12). Urinary system, part 1: Crash course A&P #38 [Video]. YouTube. https://www.youtube.com/watch?v=l128tW1H5a8

[CrashCourse]. (2015, June 22). Urinary system, part 2: Crash course A&P #39 [Video]. YouTube. https://youtu.be/DlqyyyvTI3k

Innovation for Patient Care. (2020, October 16). Renal cell carcinoma: The most common form of kidney cancer in adults. https://www.ipsen.ca/therapeutic-areas/oncology/renal-cell-carcinoma/

Johns Hopkins Medicine. (n.d.). Computed tomography (CT or CAT) scan of the kidney. John Hopkins Medicine: Health. https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/ct-scan-of-the-kidney

Kidney Foundation of Canada. (2020). Dialysis. Kidney Foundation. https://kidney.ca/Kidney-Health/Living-With-Kidney-Failure/Dialysis

Lab Tests Online. (2017, July 10). 24-hour urine sample. https://labtestsonline.org/glossary/urine-24

Lab Tests Online. (2020, June 16). Urinalysis. https://labtestsonline.org/tests/urinalysis

Lab Tests Online. (2020a, January 30). Urine culture. https://labtestsonline.org/tests/urinalysis

Lights, V., & Boskey, E. (2019, March 21). Everything you need to know about urinary tract infection. Healthline. https://www.healthline.com/health/urinary-tract-infection-adults

Mayo Clinic Staff. (2019a, August 15). Chronic kidney disease. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/chronic-kidney-disease/symptoms-causes/syc-20354521

Mayo Clinic Staff. (2019, September 19). Diabetic nephropathy. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/diabetic-nephropathy/symptoms-causes/syc-20354556

Mayo Clinic Staff. (2019b, September 14). Interstitial cystitis. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/interstitial-cystitis/symptoms-causes/syc-20354357

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Image Descriptions

Figure 8.2 image description: LeftThe left panel of this figure shows the location of the kidneys in the abdomen. The right panel shows the cross section of the kidney. [Return to Figure 8.2].

Figure 8.5 image description: The left panel of this figure shows the cross section of the bladder and the major parts are labeled. The right panel shows a micrograph of the bladder. [Return to Figure 8.5].

Figure 8.6 image description: Diagrams of the (a) female and (b) male genitalia highlighting the respective urethras. [Return to Figure 8.6].

Figure 8.7 image description: This figure shows the different pressures acting across the glomerulus including blood hydrostatic pressure, blood colloid osmotic pressure, capsular hydrostatic pressure. [Return to Figure 8.7].

Figure 8.8 image description: This color chart shows 8 different shades of yellow and associates each shade with stages of hydration (lightest 3 shades) or dehydration (remaining 5 darker shades). [Return to Figure 8.8].

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Unless otherwise indicated, this chapter contains material adapted from Anatomy and Physiology (on OpenStax), by Betts, et al. and is used under a a CC BY 4.0 international license. Download and access this book for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction.

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Medical Terminology for Healthcare Professions Copyright © 2023 by Jennifer Campbell is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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