1. Urinary/Excretory System
Descending
aorta
Inferior
vena cava
Urinary System
(Excretory System)
Renal vein
Adrenal
gland
Renal
artery
Right
kidney
Left
kidney
Ureter
Ureter
Bladder
Urethra

2. Urinary System Organs Kidneys (primary excretory organ) Ureters
Bladder
Urethra
Functions
Remove nitrogenous waste product of protein metabolism and other harmful substances
Eliminates them in the form of ammonia, uric acid or urea
Eliminates controlled amounts of water and salts to maintain the internal environment
**Function is NOT to make urine
Function is to maintain homeostasis of blood (excrete wastes, absorb nutrients, maintain electrolytes, pH balance)

3. Rugae

4. Sends blood to arterioles
Receives 15-20%
of systemic blood
at rest

5. Nephron Functional Unit of Kidney
Glomerulus
Afferent
arteriole
Efferent
arteriole
Renal Corpuscle
Renal papilla

6. Nephron Up to 1 million in kidney Functions Filtration
removes dissolved substances from glomerulus (blood supply)
what remains is called the filtrate
Reabsorption
Substances from filtrate leave nephron
Reabsorb from tubule into blood or interstitial fluid
Secretion
Releases substances from blood supply or interstitial fluid into tubule
(opposite direction from reabsorption)

7. Filtration
Blood pressure forces water and dissolved substances out of the glomerulus blood into Bowman’s capsule
Dissolved substances (filtrate): H2O, glucose, amino acids, electrolytes, and wastes (no proteins or cells)
Averages 125 ml/min for both kidneys (180 liters/day)
The vast majority of the filtrate (99%) must be taken back to body’s blood supply.
Urinate (wastes) on avg ml/day (0.4 gallons)

8. Reabsorption
The return of substances from filtrate in the nephron tubule to the blood or interstitial fluid
Major Substances:
H2O - osmosis
NaCl - active transport
Glucose, amino acids - active co-transport
Some urea and other salts
PCT – most reabsorption
Descending loop – reabsorb H2O
Ascending loop & DCT – reabsorbs salt
Collecting duct – reabsorbs H2O

9. Secretion Secreted Substances: toxins and drug residues
The active release of substances INTO the nephron tubule.
Purposes:
Secreted Substances: toxins and drug residues
Electrolyte balance: K+ exchanged for Na+
Acid-base balance: H+ , NH3
Antidiuretic hormone (ADH): produced by posterior pituitary, increases water permeability of the DCT and collecting duct
Cranberry juice – acidifies urine to help discourage bacteria and some types of kidney stones; decrease UTI by inhibiting bacteria from adhering to urinary tract walls

10. Osmotic Pressure (Osmolarity)

11. Urine Micturation – process of urination Normal Urine Abnormal Urine
H2O
95%
Glucose
Recent intake of sugary foods,
Nitrogeneous wastes
urea, uric acid,
diabetes melitis (Glycosuria)
ammonia, creatine
Protein
Physical exertion, high protein;
Electrolytes
Na+, NH4+, K+,
hypertension, glomerulonephritis (Proteinuria)
Cl-, PO4-3, SO4-2
Ketone bodies
Starvation, untreated diabetes mellitus
Toxins
bacterial poisons
Hemoglobin
Hemolytic anemia, severe burns
Pigments
products of breaking down RBC,
Bile pigments
Hepatitis, cirrhosis, bile obstruction
filtered from food and drugs
Erythrocytes
Bleeding due to trauma, kidney stones,
Hormones
infection, cancer (Hematuria)
Leukocytes
Urinary tract infection

12. Disorders and Diseases
Pyuria – pus in urine
Dysuria – painful urination
Polyuria – large amounts of urine
Oliguria – very little urine
Anuria – absence of urine
Renal Calculi – crystallized calcium in renal pelvis or calyx (kidney stones)
Neurogenic bladder – involuntary urine retention, bulging bladder, burning sensation
Overactive bladder – frequent urination, pain, oliguria
UTI: bacterial infection
Urethritis: inflammation of urethra; result of gonorrhea and Chlamydia; most common in males
Cystitis: inflammation of bladder; more common in females due to shorter urethra
Nephritis: inflammation of kidney
Pyelonephritis – inflammation of renal pelvis
Renal Failure – kidney failure