Unit 7 (Chapter 17) The Urinary System

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Unit 7 (Chapter 17)The Urinary System

• Presented by Dawn Duran, PT, MHS, CSCS
• Adjunct Professor, Kaplan University

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Welcome to the Seminar!
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Kidneys

• For the formation of urine, it is essential that
  the kidney has a high rate of blood flow

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Functions of the kidneys include

• Stimulating the production of red blood cells
• Maintaining blood pressure
• Regulating water balance
• Regulating electrolytes
• Excretes toxins and nitrogenous wastes

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Kidneys

• Internal structure
• Renal cortex - outer part of the kidney
• Renal medulla - inner portion of kidney
• Renal pyramids - triangular divisions of medulla
• Renal papilla - narrow, innermost end of pyramid
• Renal pelvis - the basin-like structure that the
  urine flows into as it leaves the kidney
• Renal calycesdivisions of renal pelvis

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Kidneys

• Renal Microscopic structure
• Nephrons are the structural and functional units
  of the kidney.
• The major components of the nephron are the renal
  corpuscle and renal tubule.
• There are approximately 1-2 million nephrons in
  each kidney.
• Cortical nephrons make up 85 of total
• Juxtamedullary nephrons play a specialized role
  in concentrating urine

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Kidney

• Renal corpuscle
• Bowmans capsule is the cup-shaped top
• Glomerulus is a tuft or network of blood
  capillaries surrounded by Bowmans capsule
• An efferent tubule drains blood from the
  glomerulus while an afferent tubule carries blood
  to the glomerulus
• The primary function of the glomerulus is
  filtration. Filtration occurs in the glomerulus.
  

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Kidneys

• Renal tubule
• Proximal convoluted tubulefirst segment
• Primary function is reabsorption
• Loop of Henleextension of proximal tubule
  consists of descending limb, loop, and ascending
  limb
• Distal convoluted tubuleextension of ascending
  limb of loop of Henle
• Collecting tubulestraight extension of distal
  tubule

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Fun Facts

• Approximately 99 of water that leaves the blood
  each day is returned to the blood.
• A person can live with only one kidney

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Formation of Urine

• Occurs by a series of three processes that take
  place in successive parts of nephron filtration,
  absorption and secretion
• The formation of urine begins with filtration
• Filtration is a continuous process in renal
  corpuscles
• glomerular blood pressure causes water and
  dissolved substances to filter out of glomeruli
  into Bowmans capsule
• normal glomerular filtration rate 125 ml per
  minute
• In other words, filtration occurs in the
  glomerulus
• An increase in systemic blood pressure causes
  filtration through the glomerular-capsular
  membrane to increase.

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Formation of Urine

• Reabsorption is the movement of substances out of
  renal tubules into blood in peritubular
  capillaries
• water, nutrients, and ions are reabsorbed
• water is reabsorbed by osmosis from proximal
  tubules
• Secretion is the 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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Formation of Urine

• Urine volume excretion is regulated by hormones
  aldosterone, ADH, atrial natriuretic hormone
• Urinalysis is an examination of the physical,
  chemical, and microscopic characteristics of
  urine may help determine the presence and nature
  of a pathological condition
• Normal adult urine output is approximately
  1500-1600 mL/day
• The color of normal urine is transparent
  yellow, amber or straw colored
• Nitrogenous wastes, creatinine and urea are
  normally found in urine
• Ketones, including acetone, are not
• An acetone odor to the urine is indicative of
  diabetes mellitus

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Hormones

• Aldosterone causes the retention of salt and
  water.
• This is a salt and water retaining hormone
  secreted by the adrenal cortex.
• Secretion of aldosterone causes sodium to be
  reabsorbed. This increases blood volume.
• Secretion of aldosterone causes water to be
  retained
• ADH (Antidiuretic hormone) causes the retention
  of water and decreased urine production.
• ANH (atrial natriuretic hormone) causes salt and
  water loss.

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Ureters

• Ureters are narrow long tubes with an expanded
  upper end (renal pelvis) located inside kidney
  and lined with mucous membrane and muscular layer
• Functiondrain urine from renal pelvis to urinary
  bladder

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Urinary Bladder

• Structure
• Elastic muscular organ, capable of great
  expansion
• When the bladder is empty, the inner lining is
  wrinkled and lies in folds called rugae
• Functions
• Storage of urine before voiding
• Assist with micturition
• Voiding

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Urinary Bladder

• The openings of the ureters and the urethra in
  the urinar bladder is a triangular region called
  the trigone
• The uterus is locaed posterior and superior to
  the urinary bladder

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Urethra

• Structure
• Narrow tube from urinary bladder to exterior
• Lined with mucous membrane
• Opening of urethra to the exterior called urinary
  meatus
• In males, the urethra passes through the prostate
  gland
• The urethra is longer in men than it is in women
• Functions
• Passage of urine from bladder to exterior of the
  body in both men and women
• Passage of male reproductive fluid (semen) from
  the body
• Therefore, in women the urethra is only a
  component of the urinary tract whereas in men it
  is part of both the urinary and reproductive
  tracts

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Micturition

• Passage of urine from body (also called urination
  or voiding)
• Regulatory sphincters
• Internal urethral sphincter (involuntary)
• External urethral sphincter (voluntary)
• Bladder wall permits storage of urine with little
  increase in pressure

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Micturition

• The sacral spinal cord is involved with the
  regulation of micturition
• Emptying reflex
• Initiated by stretch reflex in bladder wall
• Bladder wall contracts
• Internal sphincter relaxes
• External sphincter relaxes, and urination
• Enuresisinvoluntary urination in young child

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Micturition

• Urinary retentionurine produced but not voided
• Incontinence is when urine is voided
  involuntarily
• May be caused by spinal injury or stroke
• Neurogenic bladderparalysis or abnormal function
  of the bladder, preventing normal flow of urine
  out of the body
• Types include urge, stress, and reflex

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Micturition

• Anuria is the absence of urine
• Oliguria is a scanty amount of urine
• Proteinuria means protein in the urine
• A common temporary condition that occurs after
  exercise in many individuals
• Glycosuria means glucose in the urine
• Glucose is not normally found in urine
• If urinalysis detects glycosuria then diabetes
  mellitus might be present

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Diuretics

• Diuretics are drugs that stimulate the production
  of urine

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Renal Urinary Disorders

• Obstructive disorders interfere with normal urine
  flow, possibly causing urine to back up and cause
  kidney damage
• Renal calculi (kidney stones) may block ureters,
  causing intense pain called renal colic
• Lithotripsy is a process where kidney stones are
  broken up by ultrasound waves
• Kidney stones are NOT a type of cancer.
• Tumorsrenal cell carcinoma (kidney cancer) and
  bladder cancer are often characterized by
  hematuria (blood in the urine)

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Renal Urinary Disorders

• Urinary tract infections (UTIs) are often caused
  by gram-negative bacteria
• Urethritisinflammation of the urethra
• Cystitisinflammation or infection of the urinary
  bladder
• Pyelonephritisinflammation of the renal pelvis
  and connective tissues of the kidney may be
  acute (infectious) or chronic (autoimmune)

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Renal Urinary Disorders

• Glomerular disorders result from damage to the
  glomerularcapsular membrane of the renal
  corpuscles
• Nephrotic syndrome accompanies many glomerular
  disorders
• Proteinuriaprotein in the urine
• Hypoalbuminemialow plasma protein (albumin)
  level caused by loss of proteins to urine
• Uremia - a condition where dangerous levels of
  toxins build up in the blood

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Renal Urinary Disorders

• Kidney failure or renal failure occurs when the
  kidney fails to function
• Acute renal failureabrupt reduction in kidney
  function that is usually reversible

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Renal Urinary Disorders

• Chronic renal failureslow, progressive loss of
  nephrons caused by a variety of underlying
  diseases
• Early in this disorder, healthy nephrons often
  compensate for the loss of damaged nephrons
• Loss of kidney function ultimately results in
  uremia (reflected by high BUN levels) and its
  life-threatening consequences
• Complete kidney failure results in death unless a
  new kidney is transplanted or an artificial
  kidney substitute is used

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Questions? Ask Me OR your classmates!
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Thanks for attending! See you in Discussion!