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The Excretory System
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Excretion: Removes human waste from the bodyMicturition: when you urinate 1,800 L of blood are filtered by the kidneys daily, 1.5L of urine are produced 99% of filtrate is reabsorbed
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Functions in ExcretionDetoxify Blood (filters or changes to inactive forms)Excretes Bile (Worn out RBC, bile salts)Forms Urea (changes toxic ammonia to urea)
Urea → Blood → Kidneys
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Excretory System
Made up of:
two kidneys, two ureters, 1 bladder1 urethra
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Ureters are tubes that carry urine to the bladder
Bladder temporarily stores urine
Urethra is the tube that carries urine from the urinary bladder to the outside of the body
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The Kidney
two layers: medulla and cortex
filtering units called nephrons
renal artery and renal vein s
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The KidneyThe kidneys are fist-sized, bean shaped structures
two layers: medulla and cortex
filtering units called nephrons
renal artery and renal vein
Tuesday, December 19, 17
The KidneyThe kidneys are fist-sized, bean shaped structures
two layers: medulla and cortex
filtering units called nephrons
renal artery and renal vein
cortex
medulla
renal artery
renal vein
ureter
(to bladder)
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Kidney1. Eliminate metabolic waste, especially nitrogen in urea 2. Maintains H2O balance (ADH)3. Blood volume/pressure (aldosterone)4. Regulates pH via buffer systems 5. Regulates mineral composition of the body (aldosterone) will filter all electrolytes in fluid and return only what is useful to the blood
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NephronNephrons are the filtering units in the kidneys.
They clean and rebalance the blood to produce urine.
There approximately 1 million nephrons in each kidney
loop of Henle
from body
to body
to body
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Nephrons clean the blood in a three-step process:
FiltrationReabsorptionExcretion
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FiltrationWater, electrolytes, amino acids, glucose, urea, and other small molecules diffuse out of the blood, creating the filtrate.
Glomerulus: Network of capillaries
Bowman’s Capsule: Encases the glomerulus
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FiltrationWater, electrolytes, amino acids, glucose, urea, and other small molecules diffuse out of the blood, creating the filtrate.
Glomerulus
Bowman’s capsule
Glomerulus: Network of capillaries
Bowman’s Capsule: Encases the glomerulus
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from body
to body
collecting duct
from other nephronsloop of Henle
ReabsorptionAs the filtrate enters the rest of the tubule, most of the materials are reabsorbed into the blood.
Materials not reabsorbed make up the urine, which flows into the loop of Henle.
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from body
to body
collecting duct
from other nephrons
loop of Henle
Excretion
In the loop of Henle, water can be reabsorbed one final time to reduce the volume of urine. The remaining urine flows into a collecting duct that leads to the ureter.
Tuesday, December 19, 17