The Urinary System: Kidneys and Formation of Urine

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

2. Welcome to the Seminar! Welcome to the Seminar!

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

4. Functions of the kidneys include: Functions of the kidneys include: Stimulating the production of red blood cells Stimulating the production of red blood cells Maintaining blood pressure Maintaining blood pressure Regulating water balance Regulating water balance Regulating electrolytes Regulating electrolytes Excretes toxins and nitrogenous wastes Excretes toxins and nitrogenous wastes

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

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

7. Kidney Kidney Renal corpuscle Renal corpuscle Bowmans capsule is the cup-shaped top Bowmans capsule is the cup-shaped top Glomerulus is a tuft or network of blood capillaries surrounded by Bowmans capsule 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 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. The primary function of the glomerulus is filtration. Filtration occurs in the glomerulus.

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

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

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

11. Formation of Urine Formation of Urine Reabsorption is the movement of substances out of renal tubules into blood in peritubular capillaries Reabsorption is the movement of substances out of renal tubules into blood in peritubular capillaries water, nutrients, and ions are reabsorbed; water, nutrients, and ions are reabsorbed; water is reabsorbed by osmosis from proximal tubules 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 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; hydrogen ions, potassium ions, and certain drugs are secreted by active transport; ammonia is secreted by diffusion ammonia is secreted by diffusion

12. Formation of Urine Formation of Urine Urine volume excretion is regulated by hormones: aldosterone, ADH, atrial natriuretic hormone 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 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 Normal adult urine output is approximately 1500-1600 mL/day The color of normal urine is transparent yellow, amber or straw colored The color of normal urine is transparent yellow, amber or straw colored Nitrogenous wastes, creatinine and urea are normally found in urine Nitrogenous wastes, creatinine and urea are normally found in urine Ketones, including acetone, are not Ketones, including acetone, are not An acetone odor to the urine is indicative of diabetes mellitus An acetone odor to the urine is indicative of diabetes mellitus

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

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

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

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

17. Urethra Urethra Structure Structure Narrow tube from urinary bladder to exterior Narrow tube from urinary bladder to exterior Lined with mucous membrane Lined with mucous membrane Opening of urethra to the exterior called urinary meatus Opening of urethra to the exterior called urinary meatus In males, the urethra passes through the prostate gland In males, the urethra passes through the prostate gland The urethra is longer in men than it is in women The urethra is longer in men than it is in women Functions Functions Passage of urine from bladder to exterior of the body in both men and women Passage of urine from bladder to exterior of the body in both men and women Passage of male reproductive fluid (semen) from the body 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 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 Micturition Passage of urine from body (also called urination or voiding ) Passage of urine from body (also called urination or voiding ) Regulatory sphincters Regulatory sphincters Internal urethral sphincter (involuntary) Internal urethral sphincter (involuntary) External urethral sphincter (voluntary) External urethral sphincter (voluntary) Bladder wall permits storage of urine with little increase in pressure Bladder wall permits storage of urine with little increase in pressure

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

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

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

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

23. Renal & Urinary Disorders Renal & Urinary Disorders Obstructive disorders interfere with normal urine flow, possibly causing urine to back up and cause kidney damage 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 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 Lithotripsy is a process where kidney stones are broken up by ultrasound waves Kidney stones are NOT a type of cancer. 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) Tumorsrenal cell carcinoma (kidney cancer) and bladder cancer are often characterized by hematuria (blood in the urine)

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

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

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

27. Renal & Urinary Disorders Renal & Urinary Disorders Chronic renal failureslow, progressive loss of nephrons caused by a variety of underlying diseases 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 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 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 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! Questions? Ask Me OR your classmates!

29. Thanks for attending! See you in Discussion! Thanks for attending! See you in Discussion!