Anatomy of Urinary System

1. Anatomy of Urinary System
By Shemsedin A.

2. Learning Outcomes
30-2
.1 Describe the structure, location, and functions of the kidney.
.2 Define the term nephron and describe its structure.
.3 Explain how nephrons filter blood and form urine.
.4 List substances normally found in urine.
1/9/2024
By Shemsedin A.

3. Learning Outcomes (cont.)
30-3
.5 Describe the locations, structures, and functions of the
ureters, bladder, and urethra.
.6 Explain how urination is controlled.
.7 Describe the causes, signs and symptoms, and treatments
of various diseases and disorders of the urinary system.
1/9/2024
By Shemsedin A.

4. Introduction
30-4
 System functions to remove waste products from the blood
 Main functional units of the kidneys are the nephrons
 Nephrons filter the blood and form the urine
Kidneys
Ureters
Bladder
Urethra
1/9/2024
By Shemsedin A.

5. The Kidneys
30-5
Functions
Remove metabolic waste products from the blood
Secrete the hormone erythropoietin, which stimulates
bone marrow to produce red blood cells
Secrete the hormone renin, which helps regulate blood
pressure
Description
The kidneys are bean-shaped organs that lie behind the
peritoneal cavity (retroperitoneal) on either side of the
vertebral column.
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By Shemsedin A.

6. The Kidneys (cont.)
30-6
 Renal sinus – concave depression of the surface of the kidney
 Hilum – point of entry for the renal artery, renal vein, and ureter
 Renal pelvis – expansion of the ureter that further divides into
calyces
 Renal cortex – outermost portion of the kidney that covers the
pyramids and dips down between them
 Renal medulla – middle portion that also divides into renal pyramids
 Renal column – portion of the cortex between pyramids
Kidney
1/9/2024
By Shemsedin A.

7. The Kidneys: Nephrons
30-8
 Removes waste products from the blood
 Each kidney contains about 1 million nephrons
 Made of a renal corpuscle and a renal tubule
Renal
Corpuscles
 Composed of a group of capillaries
called a glomerulus
 Glomerulus is surrounded by
Bowman’s capsule
 Blood filtration occurs in corpuscle
 Extend from the Bowman’s
capsule of a nephron
 Consist of three parts:
 Proximal convoluted tubule
 Loop of Henle
 Distal convoluted tubule
Renal
Tubules
Glomerulus
1/9/2024
By Shemsedin A.

8. The Kidneys – Nephrons (cont.)
30-10
Veins of the Kidney
Afferent Arteriole
Glomerulus
Efferent Arteriole
Peritubular Capillaries
 Afferent arterioles deliver
blood to the glomeruli
 Efferent arterioles carry
blood from the glomeruli to
peritubular capillaries
1/9/2024
By Shemsedin A.

9. 30-11
Apply Your Knowledge
What are the functions of the kidney?
ANSWER: The kidney removes metabolic waste products from the blood, secretes erythropoietin to help
regulate RBC production, and secretes renin to help regulate the BP.
Correct!
1/9/2024
By Shemsedin A.

10. Urine Formation:
Glomerular Filtration
 First process occurs in renal
corpuscles
 Fluid part of the blood is forced from
glomerulous into Bowman’s capsule
 Becomes glomerular filtrate
30-12
Glomerulus

11. Urine Formation:
Glomerular Filtration (cont.)
 Factors affecting glomerular filtration
 Filtration pressure – amount of pressure that forces
filtrate from the glomerulus into Bowman’s capsule.
 Determined by blood pressure
 Rate of filtration – sympathetic nervous system control
 Constriction of afferent arterioles decreases filtration pressure
30-13

12. Urine Formation: Tubular Reabsorption
30-14
 Second process in urine formation
 Glomerular filtrate  proximal convoluted tubule
 Nutrients, water, and ions pass through the walls of the renal tubule into
the peritubular capillaries
 Water reabsorption depends on hormones
 Antidiuretic hormone (ADH)
 Aldosterone
 Both increase water reabsorption, which decreases urine production
Tubular
Reabsorption
1/9/2024
By Shemsedin A.

13. Urine Formation: Tubular Secretion
30-15
 Third process of urine
formation
 Substances move from
blood in the peritubular
capillaries into the renal
tubules
 Secreted substances
 Drugs
 Hydrogen ions
 Waste products
Tubular
Secretion
1/9/2024
By Shemsedin A.

14. Urine Formation (cont.)
30-17
 Urine composition
 Mostly water
 Urea and uric acid
 Formed by the breakdown of proteins and nucleic acids
 Trace amounts of amino acids and various ions
 Secretion of waste products helps maintain the acid-base balance
1/9/2024
By Shemsedin A.

15. 30-18
Apply Your Knowledge
Match the following:
___ Second process in urine formation A. Glomerular filtration
___ Substances move from blood into renal tubules B. Tubular reabsorption
___ Depends on filtration pressure C. Tubular secretion
___ Third process of urine formation
___ First process of urine formation
___ Filtrate flows into the proximal convoluted tubule
C
C
B
A
A
B
ANSWER:
Nice Job!
1/9/2024
By Shemsedin A.

16. Ureters, Urinary Bladder, and Urethra (cont.)
30-20
 Urinary bladder
 Expandable muscular organ
 Stores up to 600 ml urine on average
 Detrusor muscle – smooth muscle in wall of bladder
 Trigone – triangle on internal floor of bladder formed by urethra and
ureters
 Micturation
 Process of urination
 Stretching of bladder triggers process
 Approximately 150cc of urine
Bladder
1/9/2024
By Shemsedin A.

17. Ureters, Urinary Bladder, and Urethra (cont.)
30-21
 Urination
 External urethral sphincter
relaxes
 Micturation reflex – impulses
from pons and hypothalamus
 Detrusor muscle contracts
 Urine expelled
Impulses to contract
urethra; inhibit micturition
impulse until ready to
urinate
Bladder
distends
Stretch
receptors
Spinal cord
Parasympathetic nerves
stimulate detrusor muscle
Brain stem
and
cerebral
cortex
1/9/2024
By Shemsedin A.

18. Ureters, Urinary Bladder, and Urethra (cont.)
30-22
 Urethra
 Tube that moves urine from the bladder to the outside world
 Shorter in females – patient education
 Urinate when urge occurs
 Drink adequate clear fluids
 Wipe front to back
 Urinate after intercourse
1/9/2024
By Shemsedin A.

19. Apply Your Knowledge
30-23
True or False:
___ Ureters move urine by peristalsis.
___ The detrusor is formed by the openings of the ureters and urethra.
___ The process of micturition is triggered when the bladder contains about
150 ml urine.
___ The urethra move urine from the kidney to the bladder.
___ The urethra is longer in females.
___ Contraction of the detrusor muscle pushes urine from the bladder.
F
F
T
F
T
trigone
males
ureters
T
ANSWER:
1/9/2024
By Shemsedin A.

20. Diseases and Disorders of the Urinary
System
Disease/Disorder Description
Acute renal failure Sudden loss of kidney function; may be reversible with treatment
Chronic renal failure Kidneys slowly use ability to function; not reversible
Cystitis Urinary bladder infection; more common in females
Glomerulonephritis Inflammation of the glomeruli of the kidney; one cause of
chronic renal failure
Incontinence Inability to control urination
30-24

21. Diseases and Disorders of the Urinary System
Disease/Disorder Description
Polycystic kidney
disease
Enlargement of kidneys because of the presence of
many cysts within them; slow, progressive disease
Pyelonephritis Complicated urinary tract infection; starts with a
bladder infection and spreads to both kidneys; can be
acute or chronic
Renal calculi Kidney stones; can become lodged in ducts within
kidneys or ureters
30-25

22. 30-26
Apply Your Knowledge
Matching:
___ Complicated urinary tract infection A. Pyelonephritis
___ Inability to control urination B. Glomerulonephritis
___ Kidney stones C. Incontinence
___ Slow loss of kidney function D. Chronic renal failure
___ Bladder infection E. Renal calculi
___ Inflammation of the glomeruli F. Cystitis
___ Kidney enlargement due to cysts G. Acute renal failure
___ Sudden loss of kidney function H. Polycystic kidney disease
H
G
F
E
D
C
B
A
ANSWER:
GOOD JOB !
1/9/2024
By Shemsedin A.

23. In Summary
30-27
 The organs of the urinary system include the kidneys, ureters,
bladder, and urethra
 The kidneys remove metabolic waste products from the blood and
secrete erythropoietin and renin
 Urine travels through the ureters to the bladder
 Stretching of the bladder triggers micturition reflex
 Urine travels from the bladder through the urethra to the outside
world
1/9/2024
By Shemsedin A.

24. 30-28
This too shall pass—
just like a kidney
stone.
~
1/9/2024
By Shemsedin A.