AHS IAHS I

Functions of Urinary System Functions of Urinary System Excretion – removing nitrogenous Excretion – removing nitrogenous

wastes, certain salts and excess wastes, certain salts and excess water from blood.water from blood.

Maintain acid-base balanceMaintain acid-base balance Secrete waste products in the form Secrete waste products in the form

of urineof urine Eliminate urine from bladderEliminate urine from bladder

KIDNEYSKIDNEYS Bean-shaped organsBean-shaped organs

Located between Located between peritoneum and the peritoneum and the back muscles back muscles (RETROPERITONEAL)(RETROPERITONEAL)

RENAL PELVIS – funnel RENAL PELVIS – funnel shaped structure at shaped structure at the beginning of the the beginning of the ureterureter

MEDULLA MEDULLA Inner, striated Inner, striated

layerlayer Striated cones are Striated cones are

RENAL PYRAMIDSRENAL PYRAMIDS Base of each Base of each

pyramid faces pyramid faces cortex, while apex cortex, while apex empties into empties into cuplike cavities cuplike cavities called CALYCEScalled CALYCES

CORTEXCORTEX Composed of Composed of

millions of millions of microscopic microscopic functional units functional units called nephronscalled nephrons

Outer layer of the Outer layer of the kidneykidney

NEPHRONNEPHRON Functional unit of the Functional unit of the

kidneykidney Parts include:Parts include:

Bowman’s capsule Bowman’s capsule (double walled, surrounds (double walled, surrounds the glomerulus)the glomerulus)

Glomerulus (filters)Glomerulus (filters) Proximal convoluted Proximal convoluted

tubuletubule Loop of HenleLoop of Henle Distal convoluted tubuleDistal convoluted tubule Collecting tubuleCollecting tubule

Urine Formation in the NephronUrine Formation in the Nephron

FiltrationFiltration

ReabsorptionReabsorption

SecretionSecretion

FILTRATIONFILTRATION First step in urine formationFirst step in urine formation Blood from renal artery enters glomerulusBlood from renal artery enters glomerulus High blood pressure in glomerulus forces High blood pressure in glomerulus forces

fluid (FILTRATE) to filter into Bowman’s fluid (FILTRATE) to filter into Bowman’s capsulecapsule

Filtrate does not contain plasma proteins or Filtrate does not contain plasma proteins or RBCs – they’re too bigRBCs – they’re too big

Bowman’s capsule filters out 125cc of Bowman’s capsule filters out 125cc of fluid/min. – 7500cc/hourfluid/min. – 7500cc/hour

As filtrate continues through nephron, 90% of As filtrate continues through nephron, 90% of water is reabsorbedwater is reabsorbed

REABSORPTIONREABSORPTION Water and useful substances are Water and useful substances are

reabsorbedreabsorbed If blood levels of certain substances If blood levels of certain substances

are high (glucose, amino acids, are high (glucose, amino acids, vitamins, sodium) then those vitamins, sodium) then those substances will not be reabsorbed substances will not be reabsorbed

SECRETIONSECRETION Opposite of reabsorptionOpposite of reabsorption Secretion transports substances from Secretion transports substances from

blood into collecting tubulesblood into collecting tubules Substances include creatinine, Substances include creatinine,

hydrogen ions, potassium ions, and hydrogen ions, potassium ions, and some drugssome drugs

Electrolytes are selectively secreted Electrolytes are selectively secreted to maintain body’s acid-base balance to maintain body’s acid-base balance

Urinary OutputUrinary Output Ave = 1500 ml/dayAve = 1500 ml/day URINALYSIS – examination of urine to URINALYSIS – examination of urine to

determine presence of blood cells, determine presence of blood cells, bacteria, acidity level, specific bacteria, acidity level, specific gravity and physical characteristics gravity and physical characteristics (color, clarity and odor)(color, clarity and odor)

URETERSURETERS One from each kidneyOne from each kidney Carry urine from kidney to bladderCarry urine from kidney to bladder Smooth muscle tube with mucous Smooth muscle tube with mucous

membrane liningmembrane lining Peristalsis pushes urine down uretersPeristalsis pushes urine down ureters

URINARY BLADDERURINARY BLADDER Hollow, muscular organHollow, muscular organ Made of elastic fibers Made of elastic fibers

and involuntary muscleand involuntary muscle Stores urine – usually Stores urine – usually

about 500ccabout 500cc Emptying urine Emptying urine

(voiding) is involuntary (voiding) is involuntary but controlled through but controlled through nervous system nervous system (voluntary)(voluntary)

Urine leaves through Urine leaves through URETHRA to outside URETHRA to outside opening = URINARY opening = URINARY MEATUSMEATUS

Control of Urinary SecretionControl of Urinary Secretion Chemical ControlChemical Control

Reabsorption of H20 Reabsorption of H20 in distal convoluted in distal convoluted tubule controlled by tubule controlled by ADH (antidiuretic ADH (antidiuretic hormone)hormone)

Secretion and Secretion and regulation of ADH regulation of ADH controlled by controlled by hypothalamushypothalamus

DIURETICS inhibit DIURETICS inhibit reabsorption of H20reabsorption of H20

Nervous ControlNervous Control Direct control Direct control

through nerve through nerve impulses on kidney impulses on kidney blood vesselsblood vessels

Indirect control Indirect control though stimulation though stimulation of endocrine glandsof endocrine glands

RENAL CALCULI (Kidney Stones)RENAL CALCULI (Kidney Stones)

Made of crystals of calcium phosphate and Made of crystals of calcium phosphate and uric aciduric acid

Gradually they get larger until they block Gradually they get larger until they block uretersureters

First symptom – severe painFirst symptom – severe pain Other symptoms – nausea and vomiting, Other symptoms – nausea and vomiting,

frequency, chills, fever, hematuriafrequency, chills, fever, hematuria Diagnosis – by symptoms, ultrasound, or x-ray Diagnosis – by symptoms, ultrasound, or x-ray Rx – increase fluids to flush out stone, Rx – increase fluids to flush out stone,

medications, and if needed – LITHOTRIPSY medications, and if needed – LITHOTRIPSY

LITHOTRIPSYLITHOTRIPSY Surgical procedure to remove kidney Surgical procedure to remove kidney

stonesstones Shock waves hit dense stones and Shock waves hit dense stones and

break them upbreak them up Done on outpatient basisDone on outpatient basis

Urinary Disorders…Urinary Disorders… NEPHRITISNEPHRITIS

Inflammation of the Inflammation of the kidney (kidney kidney (kidney infection)infection)

CYSTITISCYSTITIS Inflammation of the Inflammation of the

mucous membrane mucous membrane lining of the urinary lining of the urinary bladderbladder

Most common cause – Most common cause – E. ColiE. Coli

Symps – DYSURIA Symps – DYSURIA (painful urination) and (painful urination) and frequencyfrequency

Usually in females Usually in females (shorter urethra)(shorter urethra)

Rx – antibioticsRx – antibiotics

INCONTINENCE INCONTINENCE – – involuntary urinationinvoluntary urination DIALYSIS DIALYSIS

(HEMODIALYSIS)(HEMODIALYSIS) Used for kidney failureUsed for kidney failure Involves the passage of Involves the passage of

blood through device blood through device with semipermeable with semipermeable membrane membrane

Dialysis serves as Dialysis serves as substitute kidneysubstitute kidney

Blood from patient Blood from patient flows through machine flows through machine and is filteredand is filtered

Can be done at home or Can be done at home or in clinicin clinic

Takes 2-4 hours, 2-3 Takes 2-4 hours, 2-3 times a week times a week

Urinary Disorders…Urinary Disorders… KIDNEY TRANSPLANTKIDNEY TRANSPLANT

As a last resortAs a last resort Involves donor organ Involves donor organ

from someone with a from someone with a similar immune systemsimilar immune system

Main complication – Main complication – rejectionrejection

ENURESIS – ENURESIS – bedwettingbedwetting

GLYCOSURIA – sugar in GLYCOSURIA – sugar in urineurine

NOCTURIA – frequent NOCTURIA – frequent urination at nighturination at night

POLYURIA – large POLYURIA – large amounts of urineamounts of urine

PYURIA – pus in urinePYURIA – pus in urine ANURIA – no urine ANURIA – no urine

producedproduced HEMATURIA – blood in HEMATURIA – blood in

urineurine DIURETIC – drug or DIURETIC – drug or

substance to increase substance to increase urine productionurine production