Urinary System
JI YON OH
LYNN SCHRECK
Functions
 Gets rid of wastes
 Maintains the water levels
 Maintains mineral and vitamin levels
 Monitors blood pH
Locations
Kidneys
 Helps maintain homeostasis
 Secretes the hormone erythropoietin
 Activation of vitamin D
 Helps to maintain blood volume and blood pressure
Kidneys
Urinary Bladder
Stores urine and forces it into the urethra.
Pathway of blood within a kidney
Nephron
Basic structural and functional unit of kidney
Renal corpuscle
• Consists of a glomerulus and a glomerulus
capsule
Renal tubule
• Extends from the renal corpuscle to the
collecting duct
Glomerular Filtration
Tubular Reabsorption & Secretion
Urea and Uric Acid Excretion
 Urea: by-product of amino acid catabolism
 Uric acid: product of the metabolism of certain
organic bases in nucleic acids
 The kidneys remove the nitrogenous wastes such as
urea from the blood
Urine Elimination
 Pressure of urine stimulates sensory nerve fibers in stretch receptors
 Transmit their sensory impulses through pelvic nerve fibers to the voiding
reflex center
 These fibers then synapse through interneurons to the anterior portion of the
spinal-cord
 Motor impulses are then transmitted
 Causes bladder to contract and open the internal urinary sphincter
 Another reflex signals the external urethral sphincter to relax
 Bladder empties and urine goes through urethra
Diseases
Glomerulonephritis
 Glomerular capillaries




are inflamed
More permeable to
proteins
Protein concentration in
blood plasma decreases
Plasma colloid osmotic
pressure decreases
Less tissue fluid moves
into the capillaries
Diseases
Kidney stones
 Composed of uric acid,
calcium oxalate,
calcium phosphate, or
magnesium phosphate
 Cause nausea and
vomiting, and blood in
the urine
Diseases
Kidney failure
 Temporary or chronic
 inability of the kidneys
to filter waste from the
blood
Works Cited
 Boundless. “Overview of Urine Formation Steps.” Boundless.com. 14
Nov. 2014. Web. 02 April 2015 <https://www.boundless.com
/physiology/textbooks/boundless-anatomy-and-physiology-text
book/the-urinary-system-25/kidney-physiology-240/overviewof-urine-formation-steps-1171-2197>.
 Marcus, RN. “Urinary Elimination.” Scribd. 2013. Web. 02 Apirl 2015
<http://www.scribd.com/doc/6135169/Urinary-Elimination#sc
ribd>.
 Biology Questions and Answers. “The Excretory System Easy Review.”
2003. Web. 02 April 2015 <http://www.biology-questions-and-a
nswers.com/the-excretory-system.html>.