1. Unit 7 (Chapter 17) The Urinary System
Presented by Dawn Duran, PT, MHS, CSCS
Adjunct Professor, Kaplan University

2. Welcome to the Seminar!

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

4. 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

5. 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 calyces—divisions of renal pelvis

6. 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

7. Kidney Renal corpuscle Bowman’s capsule is the cup-shaped top
Glomerulus is a tuft or network of blood capillaries surrounded by Bowman’s 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.

8. Kidneys Renal tubule Proximal convoluted tubule—first segment
Primary function is reabsorption
Loop of Henle—extension of proximal tubule; consists of descending limb, loop, and ascending limb
Distal convoluted tubule—extension of ascending limb of loop of Henle
Collecting tubule—straight extension of distal tubule

9. 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

10. 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 Bowman’s 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.

11. 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

12. 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 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

13. 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.

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

15. Urinary Bladder Structure Functions
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

16. 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

17. Urethra Structure Functions
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

18. 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

19. 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
Enuresis—involuntary urination in young child

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

21. 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

22. Diuretics
Diuretics are drugs that stimulate the production of urine

23. 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.
Tumors—renal cell carcinoma (kidney cancer) and bladder cancer are often characterized by hematuria (blood in the urine)

24. Renal & Urinary Disorders
Urinary tract infections (UTIs) are often caused by gram-negative bacteria
Urethritis—inflammation of the urethra
Cystitis—inflammation or infection of the urinary bladder
Pyelonephritis—inflammation of the renal pelvis and connective tissues of the kidney; may be acute (infectious) or chronic (autoimmune)

25. Renal & Urinary Disorders
Glomerular disorders result from damage to the glomerular–capsular membrane of the renal corpuscles
Nephrotic syndrome accompanies many glomerular disorders
Proteinuria—protein in the urine
Hypoalbuminemia—low plasma protein (albumin) level; caused by loss of proteins to urine
Uremia - a condition where dangerous levels of toxins build up in the blood

26. Renal & Urinary Disorders
Kidney failure or renal failure occurs when the kidney fails to function
Acute renal failure—abrupt reduction in kidney function that is usually reversible

27. Renal & Urinary Disorders
Chronic renal failure—slow, 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

28. Questions? Ask Me OR your classmates!

29. Thanks for attending! See you in Discussion!