Anatomy

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Anatomy Physiology

• Tri-State Business Institute
• Micheal H. McCabe, EMT-P

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The Urinary Tract

• Kidneys
• Ureters
• Urinary Bladder
• Urethra
• Urinary Meatus

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Kidneys

• Located Retroperitoneal space, base of rib
  cage, adjacent to floating ribs
• Right kidney usually lower than the left
• The left and right renal arteries provide blood
  flow from aorta to the kidneys.

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Internal Structure

• Cortex outer layer of kidney
• Medulla internal portion of kidney
• Pyramids triangular divisions of medulla
• Papilla long narrow end of pyramid.
• Calyses divisions of renal pelvis

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Internal Structure
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Microscopic Structure

• Nephrons are microscopic functional units of
  kidney function
• Each nephron serves as a filter that removes
  toxins and nitrogenous waste from the blood.
  Nephrons also help maintain the fluid balance,
  regulate chemical levels, and secrete renin a
  hormone that regulates blood pressure.

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Internal Structure

• Each nephron has two primary components
• Renal Corpuscle
• Renal Tubule

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Renal Corpuscle

• Consists of Bowmans capsule with its glomerulus
• Bowmans Capsule the cup-shaped top.
• Glomerulus network of blood capillaries
  surrounded by Bowmans Capsule.

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Renal Tubule

• Proximal convoluted tubule first segment
• Loop of Henle extension of proximal tubule
  consists of descending limb, loop, and descending
  limb.
• Distal Convoluted Tubule extension of ascending
  limb of loop of Henle
• Collecting Tubule straight extension of distal
  tubule.

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Functions

1. Excretes toxins and nitrogenous waste.
2. Regulates levels of many chemicals in the blood
3. Maintains water balance
4. Helps regulate blood pressure by secretion of
   renin

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Formation of Urine

• Occurs by a series of three processes that take
  place in successive parts of the nephron.
• Control of urine volume is regulated mainly by
  anti-diuretic hormone which suppresses it.

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Filtration Process

• Is continuous as long as blood flows through the
  kidney.
• Blood pressure in glomerulus causes water and
  dissolved substances to filter out of glomeruli
  into Bowmans capsule.
• Normal filtration rate is 125 ml per minute.

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Re-absorbtion

• Movement of substances out of renal tubules into
  blood in peritubular capillaries.
• Water, nutrients, and ions are reabsorbed into
  bloodstream.
• Water is reabsorbed by osmosis in proximal
  tubules.

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Secretion

• Movement of substances into urine in the distal
  and collecting tubules from blood in peritubular
  capillaries
• Hydrogen ions, potassium ions, and certain drugs
  are secreted by active transport.
• Ammonia is secreted by diffusion.

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Characteristics of Urine

• Color Transparent yellow / amber / or straw
  colored
• Odor slight odor
• pH 4.6 to 8.0
• Specific Gravity 1.001 to 1.035

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Composition of Urine

• Mostly water
• Normally contains mineral ions including Na, Cl,
  and K.
• Nitrogenous waste including ammonia, creatinine,
  urea, and uric acid
• Suspended solids (sediment)
• Urine Pigments

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Abnormal Characteristics

• Abnormal color or cloudiness indicating blood,
  bile, bacteria, drugs, food pigments, or
  high-solute concentrate.
• Acetones, ketones, nitrites
• Albumin (protein)
• Glucose
• High specific gravity can lead to precipitates
  that form kidney stones.

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Typical Lab Values for Urine

• Acetone normally none acetone in urine can
  indicate fasting, starvation, or diabetic
  ketoacidosis
• Acetoacetate normally none
• Albumin normally trace amounts albumin may
  indicate hypertension, kidney disease, or recent
  strenuous exercise

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Typical Lab Values for Urine

• Ammonia 20 to 70 mEq/L increases in liver
  disease and diabetes
• Bile and bilirubin normally absent may be
  present if bile ducts are obstructed
• Calcium Less than 150 mg/day.
  Hyperparathyroidism causes increase.
  Hypoparathyroidism causes decrease.

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Typical Lab Values for Urine

• Osmolarity 500 to 800 mOsm / L increases in
  dehydration and heart failure. Decreases in
  diabetes insipidus and aldosteronism
• pH 4.6 to 8.0 increases in alkalosis and
  during urinary infections decreases in acidosis,
  dehydration, and emphysema

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Typical Lab Values for Urine

• Potassium (K) 25 to 100 mEq / L increases in
  dehydration and chronic renal failure. Decreases
  during diarrhea, vomiting, and adrenal
  insufficiency
• Sodium (Na) 75 to 200 mg / day. Increases in
  starvation and dehydration. Decreases in acute
  renal failure and in Cushings syndrome.

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Typical Lab Values for Urine

• Creatinine Clearance 100 to 140 ml / min
  increases in kidney disease
• Creatinine 1-2 grams per day increases during
  infection. Decreases in some kidney diseases and
  in some forms of anemia.
• Glucose normally zero increases in diabetes
  mellitus, hyperthyroidism, and hypersecretion of
  adrenal cortex.

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Typical Lab Values for Urine

• Urea clearance -- gt40 ml blood cleared per
  minute increases in some kidney diseases
• Urea 25 to 35 g / day increases in some liver
  diseases and hemolytic anemia. Decreases during
  obstruction of bile ducts and severe diarrhea

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Typical Lab Values for Urine

• Uric Acid 0.5 to 1.0 grams per day increases
  in gout. Decreases in some kidney diseases.

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Microscopic Examination of Urine

• Bacteria -- lt 10,000 / ml increases during
  urinary tract infections.
• Erythrocytes trace increases in
  pyelonephritis, damage from renal stones,
  infection, and cancer
• Leukocytes trace increases during infection

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Microscopic Examination of Urine

• Blood Cell Casts (RBC) trace increases in
  pyelonephritis
• Blood Cell Casts (WBC) trace increases during
  infection
• Crystals trace increases during urinary
  retention. Very large crystals are renal calculi

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Microscopic Examination of Urine

• Epithelial Casts trace increases in some
  kidney disorders and heavy metal toxicity
• Granular Casts trace increases in some kidney
  disorders
• Hyaline Casts trace increases in some kidney
  disorders and fever.

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Ureters

• Structure long narrow tubes with expanded upper
  end (renal pelvis) located inside kidney and
  lined with mucous membrane.
• Function drain urine from renal pelvis to
  urinary bladder.

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Urinary Bladder

• Structure
• Elastic muscular organ, capable of great
  expansion
• Lined with mucous membrane arranged in rugae,
  just like stomach lining
• Function
• Storage of urine before micturation
• Micturation

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Urethra

• Structure
• Narrow tube from urinary bladder to exterior of
  body
• Lined with mucous membranes
• Function
• Passage of urine from bladder to exterior of body
• Passage of semen from prostate gland to exterior
  of body when mating.

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Micturation

• Micturation is the passage of urine from the
  body.
• Also called voiding or urination.

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Regulatory Sphincters

• Internal Urethral Sphincter involuntary
• External Urethral Sphincter voluntary

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Bladder Wall

• Expands as urine collects
• Permits storage of urine with little increase in
  pressure
• A full bladder triggers the stretch reflex

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Emptying Reflex

• Initiated by stretch reflex in bladder wall.
• Bladder wall contracts
• Internal sphincter relaxes
• External sphincter relaxes and urination occurs.

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Urinary Retention

• Kidneys produce urine
• Urine collects in the bladder
• Urine is not voided due to obstruction or failure
  of the voiding reflex

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Urinary Suppression

• Bladder is normal but no urine is produced by
  kidneys.

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Incontinence

• Urine is voided involuntarily
• May be caused by spinal injury or stroke
• Retention of urine may cause cystitis
  (inflammation of the bladder)

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Renal and Urinary Disorders

• Obstructive Disorders
• Urinary Tract Infections
• Glomerular Disorders
• Renal Failure

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Obstructive Disorders

1. Interfere with normal urine flow
2. Urine may back up and cause hydronephrosis or
   other kidney damage
3. Renal Calculi (kidney stones) may block ureters,
   causing intense pain called renal colic
4. Neurogenic bladder paralysis or abnormal
   function of bladder, preventing normal flow of
   urine out of the blody
5. Tumors renal cell carcinoma and bladder cancer
   are often characterized by hematuria

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Urinary Tract Infections

• Are often caused by gram-negative bacteria
• Urethritis inflammation of the urethra
• Cystitis inflammation of the bladder
• Pyelonephritis inflammation of the renal pelvis
  and connective tissue may be
• Acute (infectious)
• Chronic (autoimmune)

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Urinary Catheterization

• Involves insertion of a urinary catheter through
  the urethra and into the bladder for the
  withdrawal of urine
• Urine is collected in a bag strapped to the leg
  or attached to the bed rail
• Commonly performed as a diagnostic procedure and
  as a treatment for urinary retention.

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Urinary Catheterization

• Requires aseptic technique
• UTI is a common complication of catheterization
• Approximately 8 of patients who are catheterized
  develop a UTI
• Infection can ultimately kill a significant
  number of patients

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Glomerular Disorders

• Nephrotic Syndrome
• Acute Glomerulonephritis
• Chronic Glomerulonephritis

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Nephrotic Syndrome

• Nephrotic syndrome accompanies many glomerular
  disorders
• Characterized by
• Protein in the urine
• Low plasma protein caused by loss of proteins
  to urine
• Edema tissue swelling caused by loss of water
  from plasma due to hypoalbuminemia

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Acute Glomerulonephritis

• Is usually caused by a delayed immune response to
  a streptococcal infection
• May lead to renal failure
• Similar to rheumatic heart disease autoimmune
  response causes end-organ damage

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Chronic Glomerulonephritis

• Typically presents as a slow, progressive
  inflammatory condition
• Believed to be an autoimmune disorder
• Often leads to renal failure

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Renal Failure

• Acute Renal Failure an abrupt reduction in
  kidney function that is usually reversible.
• Chronic Renal Failure slow, progressive loss of
  nephrons caused by a variety of underlying
  diseases.

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Acute Renal Failure

• An abrupt reduction in kidney function
  characterized by oliguria and a sharp rise of
  nitrogenous compounds in the blood.
• Often assessed by the blood urea nitrogen (BUN)
  test a high BUN indicates failure of the kidneys
  to remove urea from the blood
• May be caused by trauma, hemorrhage. severe
  burns acute glomerulonephritis, pyelonephritis,
  or obstruction of the urinary tract.
• If the underlying cause can be treated
  successfully, recovery is usually rapid and
  complete.

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Chronic Renal Failure

• Presents as a slow, progressive condition
  resulting from the gradual loss of nephrons.
• Caused by many disease processes including
  infection, glomerulonephritis, tumors,
  auto-immune disorders, and obstruction of the
  urinary tract.

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Stages of Chronic Renal Failure

1. Stage One some nephrons are lost but the
   remaining nephrons compensate and maintain urine
   output.
2. Stage Two renal insufficiency. The progressive
   loss of nephrons becomes critical and the
   remaining nephrons can no longer compensate.

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Stages of Chronic Renal Failure Continued

• Stage Three End Stage Renal Disease (ESRD)
• Urine is no longer being formed
• Toxins, waste, and fluid build up in the body.
• Renal Dialysis or kidney transplant becomes
  necessary otherwise death occurs.

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Renal Dialysis

• Renal Dialysis is a mechanical process that
  removes metabolic waste from the blood and helps
  regulate the fluid and electrolyte balance during
  renal failure.

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Renal Dialysis

• Two basic methods of renal dialysis are commonly
  used
• Hemodialysis
• Peritoneal Dialysis

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Hemodialysis

• Requires arterial and venous vascular access in
  the patient
• A fistula is created surgically to join an artery
  and vein in the forearm
• A graft made of surgical tubing or a leg vein is
  used to join an artery and vein
• Permanent indwelling catheters are placed in a
  large artery and vein.

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Hemodialysis

• Arterial blood flows from the patient into a
  dialysis machine.
• The blood flows through a mechanical filter that
  removes waste products, toxins, and minerals.
• The blood is warmed, anti-coagulants are added,
  and returned to the body into a vein.

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Hemodialysis

• Patients typically require three or more
  four-hour dialysis runs per week
• Iatrogenic complications may include dehydration,
  infection, hypoglycemia, hyponatremia, and
  hypocalcemia.
• Some dialysis patients may eventually receive a
  kidney transplant.

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Peritoneal Dialysis

• 1 to 3 liters of saline is introduced into the
  peritoneal cavity
• Peritoneal membranes transfer waste products
  from the blood into the dialysis fluid
• Dialysis fluid is drained from the peritoneal
  cavity after appx. 2 hours

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Peritoneal Dialysis

• Less expensive than hemodialysis
• Does not require expensive or complex equipment
• Can be done at home

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Peritoneal Dialysis

• Not all patients are candidates for peritoneal
  dialysis
• Infection can result in peritonitis a
  potentially fatal complication