Excretory System
By Natalie Totonchy and Stephanie Kim
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Kidneys
A pair of bean shaped organs
Within the kidney there are two inner
regions, the kidney medulla and kidney
cortex
Both threaded with capillaries
They filter organic waste, water, and mineral
ions from the blood
The urinary system
helps regulate shifts
in volume and
composition of the
excess
fluid from cells
*(Source 3)
http://www.google.com/imgres?imgurl=http://img.webmd.com/dtmcms/live/webmd/consumer_assets/site_images/articles/image_article_collections/anatomy_pages/Kidney2.jpg&imgrefurl=http://www.webmd.com/urinary-incontinenceoab/picture-of-thekidneys&h=334&w=492&sz=135&tbnid=A1P32WgLGEqFyM:&tbnh=90&tbnw=133&prev=/search%3Fq%3Dkidneys%26tbm%3Disch%26tbo%3Du&zoom=1&q=kidneys&usg=__slXgQx4QMBcGC76DVLdJOBPYpUc=&docid=QJUbb1
Urine Formation
• Water along with the unwanted solutes
that the kidney filters out from the blood
• it goes from each kidney to tubular
channel called ureter
• Leads to urinary bladder where urine is
stored
• Released from the urethra
*(Source 2)
http://www.infovisual.info/03/058_en.html
Nephrons Function
• Nephrons are tiny units inside the kidneys
where the filtration process takes place.
• More than a million in each human
kidney
• Nephrons are the functional unit of
kidney, they have a lot of surface area
*Source 1
Nephron Structure
http://www.google.com/imgres?imgurl=http://legacy.owensboro.kctcs.edu/gcaplan/anat2/notes/nephron_structure.jpg&imgrefurl=http://legacy.owensboro.kctcs.edu/gcaplan/anat2/notes/APIINotes3%2520urinary%2520system.htm&h=727&w=800&sz=93&t
bnid=JhbjjXlL5GBZsM:&tbnh=90&tbnw=99&prev=/search%3Fq%3Dnephron%26tbm%3Disch%26tbo%3Du&zoom=1&q=nephron&usg=__83uTipg91QOMsuFfnw1wVc65dvI=&docid=rwdqLPs3sz5CM&sa=X&ei=xG2YUKDcIpGB0AGjtIGwAw&ved=0CD4Q9QEwAg&dur=454
Filtration
• Takes place at glomerulus (Bowman's
capsule)
• Driven by blood pressure generated from
heart's contraction.
• Forcing water and solutes out from the
glomerulus capillaries.
• Filters by size, therefore proteins do not
pass through
*Source 1
Tubular Reabsorption
• Proceeds along nephrons tubular regions
• Most filtrates- water and solute move out
of the proximal tubule wall and into the
peritubular capillaries
occurs at descending loop
water is then reabsorbed
at the distal tubule
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*Source 1
http://www.google.com/search?hl=en&client=safari&rls=en&q=nephrons+diffusion&bav=on.2,or.r_gc.r_pw.r_qf.&bpcl=37189454&biw=1202&bih=591&um=1&ie=
UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=KwyZUJ2LIcbK0AGcdQ
Tubular Secretion
• goes opposite direction of reabsorption
• cells in wall of nephron accept solutes
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from peritubular capillaries and secrete
them in loop of Henle
this process prevents certain metabolites
and foreign substances from
accumulating in blood
occurs on ascending loop
*Source 1
And Here's A Video!
http://www.youtube.com/watch?v=aQZaN
XNroVY
Red= active transport
Blue= passive transport
(Glucose and Amino Acids actively transported out)
http://www.google.com/imgres?q=nephron&hl=en&client=safari&sa=X&rls=en&biw=1202&bih=591&tbm=isch&prmd=imvns&tbnid=6Ahi4qEtGiww6M:&imgrefurl=http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/K/Kidney.html&docid=EFPAconHCi
1SyM&imgurl=http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/nephron.png&w=381&h=262&ei=IQiUULP4CrO10AH4q4DQBA&zoom=1&iact=hc&vpx=892&vpy=230&dur=17080&hovh=186&hovw=271&tx=176&ty=122&sig=106881185533082
874634&page=2&tbnh=147&tbnw=214&start=20&ndsp=24&ved=1t:429,r:11,s:20,i:235
Cell Transport
• Water passively passes through osmosis
throughout the nephron
• Loop of Henle's cells actively pumps
sodium and chloride ions out of the loop
• This makes the solution within the loop
of henle hypotonic compared to the
capillaries. This allows water to diffuse
out to the capillaries (hypertonic) during
the distal tubule
*Source 2
Homeostasis
• Maintain blood volume and pressure
• Ensure balance of sodium, chloride,
potassium, calcium, hydrogen, phosphate
and pH
*Source 3
Works Cited
1. Starr, Cecie, and Ralph Taggart. Biology: the Unity and
Diversity of Life. Pacific Grove, CA: Brooks/Cole, 2000. Print.
2. National Kidney and Urologic Disease. U.S. Department of
Health and Human Services, n.d. Web. 6 Nov. 2012.
<http://kidney.niddk.nih.gov/kudiseases/pubs/yourkidneys/>.
3.How Your Kidneys Work. National Kidney Foundation, n.d.
Web. 6 Nov. 2012.
<http://www.kidney.org/kidneydisease/howkidneyswrk.cfm>