Urinary System Urinary System Anatomy and Anatomy and PhysiologyPhysiology

Part IPart I

Urinary SystemUrinary System Kidneys (2)Kidneys (2)

Most important excretory organMost important excretory organ Eliminate wasteEliminate waste

Ureters (2)Ureters (2) Bladder (1)Bladder (1) Urethra (1)Urethra (1) Nephron UnitNephron Unit

Functional unit of the kidneyFunctional unit of the kidney Formation of urineFormation of urine Tubular and vascular structuresTubular and vascular structures

Kidney Location and Kidney Location and ProtectionProtection

Kidneys are located in the posterior Kidneys are located in the posterior wall of the abdominal cavitywall of the abdominal cavity

In the In the retroperitonealretroperitoneal space space Connective tissue (renal fascia) hold Connective tissue (renal fascia) hold

the kidneys in placethe kidneys in place Adipose tissue cushion the kidneysAdipose tissue cushion the kidneys The lower rib cage partially enclose The lower rib cage partially enclose

the kidney and protect themthe kidney and protect them

Urinary System – Urinary System – Anterior/Posterior ViewsAnterior/Posterior Views

Kidney StructuresKidney Structures

Kidney is reddish-brownKidney is reddish-brown Looks like a beanLooks like a bean Approximately 4 inches x 2 inchesApproximately 4 inches x 2 inches Hilus – indentation where blood Hilus – indentation where blood

vessels and structures enter or exit vessels and structures enter or exit the kidneythe kidney

Three RegionsThree Regions in the kidney if sliced in the kidney if sliced in half – renal cortex, renal medulla, in half – renal cortex, renal medulla, renal pelvisrenal pelvis

Renal CortexRenal Cortex

Light, outside Light, outside regionregion

Cortex means Cortex means “bark”“bark”

Renal MedullaRenal Medulla

Dark, triangular Dark, triangular structurestructure

Form small cone Form small cone shaped regions shaped regions called called renal pyramids renal pyramids

Each pyramid is Each pyramid is separated by separated by renal renal columnscolumns

The lower ends of The lower ends of the pyramids point to the pyramids point to the renal pelvisthe renal pelvis

Renal pelvisRenal pelvis A basin that collects A basin that collects

the urine made by the the urine made by the kidney and helps form kidney and helps form the upper end of the the upper end of the ureterureter

The edges of the renal The edges of the renal pelvis closest to the pelvis closest to the renal pyramids are renal pyramids are called called calycescalyces

CalycesCalyces collect the collect the urine formed in the urine formed in the kidneykidney

How do they work?How do they work?

Need a blood supplyNeed a blood supply Brought to the kidney via the renal arteryBrought to the kidney via the renal artery Renal artery stems from the abdominal aortaRenal artery stems from the abdominal aorta 20-25% of cardiac output goes to the kidneys20-25% of cardiac output goes to the kidneys Smaller arteries supply blood to the nephron Smaller arteries supply blood to the nephron

unitunit Blood leaves the kidney via the renal veinsBlood leaves the kidney via the renal veins The renal veins empty into the inferior vena The renal veins empty into the inferior vena

cavacava

Functions of the KidneysFunctions of the Kidneys

Excrete nitrogenous waste from the bodyExcrete nitrogenous waste from the body UreaUrea AmmoniaAmmonia CreatinineCreatinine

Regulate blood volume Regulate blood volume Help regulate electrolyte content of the Help regulate electrolyte content of the

bloodblood Regulate acid-base balance (pH)Regulate acid-base balance (pH) Regulate blood pressureRegulate blood pressure Regulates red blood cell productionRegulates red blood cell production

The Formation of UrineThe Formation of Urine

The The Nephron UnitNephron Unit Each kidney contains about 1 million Each kidney contains about 1 million

nephron unitsnephron units The number does not increase after The number does not increase after

birthbirth They cannot be replaced if damagedThey cannot be replaced if damaged 2 parts2 parts

Tubular component (renal tubule)Tubular component (renal tubule) Vascular componentVascular component

Renal TubulesRenal Tubules

Glomerular capsule (Bowman’s Glomerular capsule (Bowman’s Capsule) – “C” shaped capsule Capsule) – “C” shaped capsule surrounding the glomerulussurrounding the glomerulus

Glomerulus – cluster of capillariesGlomerulus – cluster of capillaries Proximal convoluted tubuleProximal convoluted tubule Loop of Henle – ascending and Loop of Henle – ascending and

descending limbdescending limb Distal Convoluted tubuleDistal Convoluted tubule Collecting ductCollecting duct

NephronNephron

Renal VasculatureRenal Vasculature Receives blood from the renal arteryReceives blood from the renal artery Renal artery branches into the afferent arteriolesRenal artery branches into the afferent arterioles Afferent arterioles feed into Bowman’s capsuleAfferent arterioles feed into Bowman’s capsule The efferent arterioles exit Bowman’s capsuleThe efferent arterioles exit Bowman’s capsule The efferent arterioles form the peritubular The efferent arterioles form the peritubular

capillariescapillaries The peritubular capillaries empty into the The peritubular capillaries empty into the

venules, large veins, and then into the renal venules, large veins, and then into the renal veinsveins

It is imperative you know the relationship It is imperative you know the relationship between the tubular and vascular structures.between the tubular and vascular structures.

Urine FormationUrine Formation

Formed in the nephron unitFormed in the nephron unit Water and dissolved substances move Water and dissolved substances move

through the renal tubules and vesselsthrough the renal tubules and vessels Three processes are involved in urine Three processes are involved in urine

formationformation Glomerular filtrationGlomerular filtration Tubular reabsorptionTubular reabsorption Tubular secretionTubular secretion

Composition of UrineComposition of Urine

SterileSterile 95 % water95 % water Nitrogen containing waste – urea, uric Nitrogen containing waste – urea, uric

acid, ammonia, creatinineacid, ammonia, creatinine Electrolytes Electrolytes Light yellow color of urine is due to a Light yellow color of urine is due to a

pigment called urochromepigment called urochrome Urochrome is formed from the Urochrome is formed from the

breakdown of hemoglobin in the liverbreakdown of hemoglobin in the liver

Urine Specific GravityUrine Specific Gravity

Ratio of the amount of solute to the total Ratio of the amount of solute to the total volumevolume

Solute = substance dissolved in the urineSolute = substance dissolved in the urine The greater the solute = greater the The greater the solute = greater the

specific gravityspecific gravity Concentrated Urine = high specific gravityConcentrated Urine = high specific gravity

Ex. dehydrationEx. dehydration Dilute Urine = low specific gravityDilute Urine = low specific gravity

Ex. Overhydration, diabetes insipidusEx. Overhydration, diabetes insipidus

Urine CharacteristicsUrine Characteristics

Amount – 1500 ml in 24 hoursAmount – 1500 ml in 24 hours pH – average 6.0pH – average 6.0 Specific Gravity – heavier than water Specific Gravity – heavier than water

(1.001-1.035)(1.001-1.035) Color – yellow (amber, straw colored, Color – yellow (amber, straw colored,

concentrated, orange, brown, red, concentrated, orange, brown, red, sediment, clear or cloudy)sediment, clear or cloudy)

Dehydrated = deep yellow, darkDehydrated = deep yellow, dark Overhydrated = pale yellow, colorlessOverhydrated = pale yellow, colorless

Abnormal Abnormal Constituents Constituents of Urineof Urine

Albumin (protein)Albumin (protein) GlucoseGlucose Red blood cellsRed blood cells HemoglobinHemoglobin White blood cellsWhite blood cells Ketone bodiesKetone bodies BilirubinBilirubin

Urine TestingUrine Testing

UrinalysisUrinalysis Microscopic examMicroscopic exam Culture and sensitivityCulture and sensitivity Urine dipstickUrine dipstick Urine Drug and alcohol screeningUrine Drug and alcohol screening 24 hour urine testing24 hour urine testing

Your Plumbing – The Your Plumbing – The Urinary TractUrinary Tract

(Ureters, Urinary bladder, (Ureters, Urinary bladder, Urethra)Urethra) UretersUreters

Transport urine, they do not alter it Transport urine, they do not alter it in any wayin any way

Urine moves in response to gravity Urine moves in response to gravity and muscular movements called and muscular movements called peristalsis through ureters.peristalsis through ureters.

Your “Plumbing”Your “Plumbing”

The BladderThe Bladder Stores urine temporarily until eliminationStores urine temporarily until elimination Located behind the symphasis pubisLocated behind the symphasis pubis A distended bladder or full bladder can be palpated A distended bladder or full bladder can be palpated

above the syphasis in the abdominal cavity.above the syphasis in the abdominal cavity. Bladder has 4 layersBladder has 4 layers

Mucous membraneMucous membrane Submucosa Submucosa Detrusor muscle – involuntary smooth muscleDetrusor muscle – involuntary smooth muscle SerosaSerosa

Contain rugae to allow for stretchingContain rugae to allow for stretching Trigone – triangular area in the floor of the bladderTrigone – triangular area in the floor of the bladder

Urination – “Micturition”Urination – “Micturition” Expelling urine from the bladderExpelling urine from the bladder The urge to urinate (void) happened at about The urge to urinate (void) happened at about

200 ml of urine in the bladder200 ml of urine in the bladder At about 300 ml urine in the bladder, the urge At about 300 ml urine in the bladder, the urge

becomes more uncomfortablebecomes more uncomfortable Moderately full = 500 ml urineModerately full = 500 ml urine Overdistended bladder may have over 1000 ml Overdistended bladder may have over 1000 ml

urineurine Bacteria in your bladder doubles every 4 hours.Bacteria in your bladder doubles every 4 hours. Stimulated by stretch receptorsStimulated by stretch receptors

UrethraUrethra Carries urine from the bladder to the outside of Carries urine from the bladder to the outside of

the body the body Internal sphincter prevents urine from Internal sphincter prevents urine from

emptying; composed of smooth muscle; emptying; composed of smooth muscle; involuntaryinvoluntary

External sphincter at the upper portion of the External sphincter at the upper portion of the urethra allows you to resist the urge to urinate; urethra allows you to resist the urge to urinate; composed of skeletal muscle; voluntarycomposed of skeletal muscle; voluntary

Female – short, opens to the outside at the Female – short, opens to the outside at the urethral meatusurethral meatus

Male – longer, passes through the prostate Male – longer, passes through the prostate gland; carries urine and spermgland; carries urine and sperm

Urinary Retention and Urinary Retention and SuppressionSuppression

Retention - Inability to voidRetention - Inability to void Post operative; anesthesiaPost operative; anesthesia Bladder dysfunctionBladder dysfunction

Suppression – no urine formationSuppression – no urine formation Kidney dysfunctionKidney dysfunction

Data Collection & Data Collection & DocumentationDocumentation

Characteristics of urine Characteristics of urine ColorColor SedimentSediment Clear or cloudyClear or cloudy OdorOdor

How does the patient/resident void?How does the patient/resident void? Urinary diversions?Urinary diversions? Signs and symptomsSigns and symptoms

UrgencyUrgency FrequencyFrequency Burning sensationBurning sensation HesitancyHesitancy

What is the Costovertebral What is the Costovertebral Angle?Angle?

Costovertebral Angle

T12

T11

L1

12th Rib

R. Kidney L. Kidney

Region to assess for kidney tenderness

Disorders of the Urinary Disorders of the Urinary SystemSystem

GlomerulonephritisGlomerulonephritis Polycystic KidneyPolycystic Kidney PyelonephritisPyelonephritis Renal Calculi – kidney stonesRenal Calculi – kidney stones Renal FailureRenal Failure UTI – urinary tract infectionUTI – urinary tract infection

As We AgeAs We Age

By age 80 there is a 50% reduction in By age 80 there is a 50% reduction in nephron units; therefore a decreased nephron units; therefore a decreased ability to concentrate urineability to concentrate urine

Urinary bladder shrinks and becomes Urinary bladder shrinks and becomes less able to contract and relax; therefore less able to contract and relax; therefore the elderly must void frequentlythe elderly must void frequently

Bladder infection incidence increasesBladder infection incidence increases Increase in bladder incontinence due to Increase in bladder incontinence due to

weakened musclesweakened muscles