J I YON OHLYNN SCHRECK

Urinary System

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 glomeru-

lus 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 cer-tain 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 recep-tors

Transmit their sensory impulses through pelvic nerve fibers to the voiding reflex center

These fibers then synapse through interneurons to the anterior por-tion 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

Glomerulonephritis

Glomerular capillaries are inflamed

More permeable to pro-teins

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 ox-alate, calcium phos-phate, or magne-sium phosphate

Cause nausea and vomiting, and blood in the urine

Diseases

Kidney failure

Temporary or chronic 

inability of the kid-neys to filter waste from the blood

Diseases

Works Cited

Boundless. “Overview of Urine Formation Steps.” Boundless.-com. 14 Nov. 2014. Web. 02 April 2015 <https://www.boundless.com /physiology/text-books/boundless-anatomy-and-physiology-text book/the-urinary-system-25/kidney-physiology-240/overview-

of-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>.