Excretory System
Do NowWhat do your kidneys do?What is excreted in urine?Explain
the pathway of urine starting in the kidneys.
Excretory SystemURINE for a real treat!!
ObjectivesTo identify the organs of the urinary system.To
explain the major functions of the urinary system.To explain the
structure of the kidney and filtration system.
The Excretory SystemFunctions:Removes certain salts and
nitrogenous wastes from bloodMaintains water and electrolyte
concentrationsRegulates pH and volume of body fluidsHelps control
RBC production and blood pressure
Major Organs and FunctionsKidneys: removes substances from
blood, form urine, regulate metabolic processes.
Ureters: transports urine from the kidneys to the bladder.
Urinary Bladder: stores urine
Tubular Urethra: excretes urine to the outside of the body.
The Kidney Where it all happens
= KIDNEYLets take a look
Nephrons!Glomerulus filters blood glomerular capsule receives
filtrate travels through proximal convoluted tubule and into loop
of Henle (descending and ascending portions) travels through distal
convoluted tubule merges in renal cortex to form collecting duct
empties into minor and then major calyxes empties into the renal
pelvis passes into the ureter! Phew that was long.Nephron
Physiology
Urine CompositionApprox 95% water!!Urea: by-product of amino
acid catabolism (allows us to determine amt. of protein in
diet!)Uric Acid: product of metabolism of certain organic
basesElectrolytes: vary with dietInteresting Fact!: you produce
between 0.6-2.5 liters per day!
MicturitionAka urinationDistension of bladder triggers stretch
receptors, generating a sensory impulse to the brain which triggers
a motor impulse to the detrusor muscle, which contracts the
bladder!Release is controlled by the external urethral sphincter
which is voluntary.
Labeling
