1. 15
The Urinary System

2. MAP

3. Parts & Functions of the Urinary System
I. Parts: 1) ___________
2) Ureters
3) ___________
4) Urethra
II. Overall FUNCTIONS
A. Produce:
B. Elimination of:
Nitrogenous wastes
Toxins
Drugs

4. Functions of the Urinary System …
C. Regulate Blood
Water balance & Blood Pressure
Electrolyte balance
Maintaining blood pH
Excrete nitrogen-containing wastes

5. II. Kidney Anatomy Location: Retroperitoneal = At T12 to L3 vertebrae
12th rib

6. B. Kidney Features
1. Renal hilum:
2. Adrenal glands:

7. 3. Nephron = Structural & Functional Unit
Cortical
nephron
Fibrous capsule
Renal cortex
Collecting
duct
Renal medulla
Renal
cortex
Proximal
convoluted
tubule
Renal pelvis
Glomerulus
Ureter
Juxtamedullary
nephron
Distal
convoluted
tubule
Loop
of Henle
Renal
medulla
(a)

8. 3. Nephron … Nephron Anatomy
Renal Artery   Afferent Arteriole
Glomerulus
Renal Tubule:
Bowman’s Capsule
Proximal Convoluted Tubule
Nephron Loop or Loop of Henle
Distal Convoluted Tubule
Collecting Duct

9. III. KIDNEY FUNCTIONING: some details A
III. KIDNEY FUNCTIONING: some details A. Basic Functions that occur in the Nephron
1. Glomerular Filtration
a. = Small substances– Water and solutes– are forced through holes in capillary walls
Nitrogenous Wastes: Urea
b. Large substances: _____________
Proteins and blood cells:
Location: between glomerulus and Bowman’s Capulse

10. 2. Tubular Reabsorption =
Water
Glucose
Amino acids
Ions
Materials not reabsorbed?
Nitrogenous waste products– Urea, Uric acid, Creatinine
Locations: Proximal Convoluted Tubule and Nephron Loop, Collecting duct mostly

11. 3. Tubular Secretion = Hydrogen and potassium ions
Location: Distal Convoluted Tubule and Loop mostly

12. Water Balance
1. Osmotic Gradient of Nephron Loops
2. Collecting Duct
3. Antidiuretic hormone (ADH)
Prevents excessive water loss in urine
Causes the kidney to reabsorb more water

13. IV. Characteristics of Urine
Amount: In 24 hours, about 1.0 to 1.8 liters
Waste products:
color
Dilute vs. concentrated
Dilute urine if:
Less urine (concentrated) if:
Sterile
pH of approx. 6

14. Characteristics of Urine …
Solutes
Sodium and potassium ions
Urea, uric acid, creatinine
Ammonia
Bicarbonate ions

15. Characteristics of Urine …
Solutes NOT in urine:
Bile

16. Abnormal Urine Constituents
KNOW
Substance
Name of Condition
Possible Causes
Glucose
Glucosuria
Excess sugary intake; diabetes mellitus
Proteins
Proteinuria
Physical exertion, pregnancy; glomerulonephritis, hypertension
Pus (WBCs and bacteria)
Pyuria
Urinary tract infection
RBCs
Hematuria
Bleeding in the urinary tract
Hemoglobin
Hemoglobinuria
Various: transfusion reaction, hemolytic anemia
Bile pigments
Bilirubinuria
Liver disease (hepatitis)

17. V. Ureters =
Function
VI. Urinary bladder
Smooth, collapsible, muscular sac
Function:
In males, the prostate gland surrounds the neck of the bladder
Bladder expansion

18. VII. Urethra Thin-walled tube Location
Females—anterior to the vaginal opening
Males—travels through the prostate and penis
Function
Females
Males

19. VIII Disorder of the Urinary System
Kidney Failure
Hemodialysis

20. IX. Fluid, Electrolyte and Acid-Base Balan ce
Water and Electrolyte Balance of Blood
- Fluid makes up 605 OF BODY WEIGHT
Intracellular Fluid, 20% of the 60%
Extracellular Fluid, 40% of the 60%
Interstitial Fluid (most of extracell fluid)
Plasma

21. B. WATER BALANCE: The Link Between Water and Salt
Solutes, Electrolytes =
Changes in solute concentration change the concentration of water
When solutes move from one location to another, this causes water to move from High to Low concentration
Alters blood volume and blood pressure
Can impair the activity of cells

22. Proper concentrations of various electrolytes must be maintained and changes in overall solute concentrations controlled
C. Regulation of water intake and output
- IMPORTANCE: affects Blood Pressure
Water Intake: controlled by Hypothalamus via thirst. Stimuli:
Increase in plasma solute content
Dry mouth
Lowered blood volume

23. Water Output
Lungs
Perspiration
Feces
Kidneys then control amount of water in urine
3. Control of Urine concentration via hormones
a. ADH produced by Pituitary Gland via instructions from hypothalamus

24. Renin produced by kidneys
- in response to low blood pressure in kidney capillaries AND
filtrate solute concentration
- Causes: increase in Aldosterone which is produced by Adrenal Gland
- If too little Na+, high aldosterone cause all Na+ to be reabsorbed by nephrons.
Increase in Na+ then holds more H2O in body  increases BP

25. 4. Control of Blood Pressure also via cardiovascular system
D. Acid-Base Balance
Most changes to blood Ph from substances produced by cells, no food
Respiratory Sys: handles CO2 levels
Urinary Sys: does other acids and alkaline substances
Bicarbonate Buffer System of blood
Respiratory Sys– via CO2

26. END Urinary System can: Excrete bicarbonate ions
Conserving bicarbonate ions
Generate new bicarbonate ions
END

27. Hepatic veins (cut) Inferior vena cava Renal artery Adrenal gland
Renal hilum
Aorta
Renal vein
Kidney
Iliac crest
Ureter
Rectum (cut)
Uterus (part
of female
reproductive
system)
Urinary
bladder
Urethra
(a)
Figure 15.1a