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Excretory System. Sarah Norton Giselle Lehman Cam Hansel. Urinary System. FUNCTION : remove waste and excess water from blood and get it out of the body in the form of urine; counters unwanted shifts in the volume and composition of extracellular fluid (8).
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Excretory System Sarah Norton Giselle Lehman Cam Hansel
Urinary System FUNCTION: remove waste and excess water from blood and get it out of the body in the form of urine; counters unwanted shifts in the volume and composition of extracellular fluid (8)
Urine Formation Helps Maintain Homeostasis - excretion regulates the water content (to ensure the correct amount is the body) in the blood by producing hypotonic or hypertonic urine (compared to blood plasma) (3) • in summer, water is lost through sweat--> urine is hypertonic (8) • no water loss from sweating in winter--> urine is hypotonic (8) - urine formation counters shifts in volume and concentration of solutes and foreign substances (like drugs) (3) - excretion regulates pH of the blood by removing waste (3)
The Kidney STRUCTURE: • in the rib cage, next to the spine, have 2 (4) • small (about 10 cm), bean-shaped (8) FUNCTION: • filters used/unwanted water, minerals, and urea (waste) from blood--returns all but 1% to blood (8) • makes that 1% into urine (~1.5 liters a day) (8) • blood pressure regulation (by secreting enzyme renin) (9) • controls production of erythropoietin, which controls red blood cell production (4) • regulates the volume, composition and pH of body fluids (1) • regulates calcium absorption via vitamin D (4)
The Nephron - tiny filtering units in the kidney, millions in cortex (8) - purifies and filtrates blood (7) - the whole nephron is made of the Renal Corpuscle (glomerulus + Bowman's capsule) and the Renal Tubule (proximal convoluted tubule+ loop of Henle) (7) -Glomerulus: ball formed of small blood capillaries (glomerular) -Bowman's capsule: nephron starts here, double-walled epithelial cup that holds the glomerulus (7) -proximal convoluted tubule:absorbs and regulates the potassium, calcium, sodium and pH of filtrate and secretes natural acids into filtrate (7) -loop of Henle: U-shaped tube, concentrates salt of the tissue around it (7) -Distal Tubule: adjustment stage, can lead to urine that is highly dillute, concentrated or in between (8) -Collecting Duct: leads to kidney's central cavity then into an ureter (8)
Filtration • blood is filtered by osmosis and diffusion in glomerulus (2) • driven by heart's contractions • blood enters through the glomular capillaries (glomerulus) in the nephron • blood pressure filters blood when it forces water and solutes (except proteins) out of the glomerular capillaries. • this protein-free solution moves into the proximal tubule • filtered fluid in the Bowman's capsule is isotonic (2) [all from source 2 and 8]
Tubular Reabsorption • happens in tubules;sodium is pumped out through active transport in loop of Henle and proximal tubule(8) • reclamation (reabsorption) of water (80%), glucose, electrolytes, amino acids, sodium, potassium, etc--restores their concentrations in blood • done by capillary network around tubules • osmosis and active transport (for glucose, amino acids). • then filtrate's water and solutes move into peritubular capillaries. [all from source 2 and 8]
Tubular Secretion • as the tubular filtrate drains, toxic substances(not filtered in the glomerulus) are secreted through the blood and tubular wall into the filtrate (in the opposite direction of reabsorption) • cells in the tubule wall accept solutes then secrete them into the nephron wall • filtered waste products make urine [all from source 2 and 8]
How does this relate to diabetes? - the kidney filters waste from the blood - in diabetes there is an excess of glucose in blood because of a lack of insulin - extra glucose is considered waste gets filtered from blood in kidney - the kidneys make that glucose (waste) into urine and thus it becomes a symptom of diabetes that glucose appears in the urine
References 1. "Anatomy and Physiology."Welcome to Kaskaskia College Faculty Homepages. N.p., n.d. Web. 4 Nov. 2010. <http://kconline.kaskaskia.edu/bcambron/Biology%20117/Anatomy%20and %20Physiology.htm>. 2."Excretion And Osmoregulation In Man, Functions Of The Kidney Tutorvista.com."Tutorvista.com - Online Tutoring, Homework Help for Math, Science, English from Best Online Tutor. Tutorvista, 2010. Web. 04 Nov. 2010. <http://www.tutorvista.com/content/biology/biology-ii/excretion-and-osmoregulation/excretion-and-osmoregulation-man.php>. 3. Franklin Institute, . "Excretory System: Poison Protection."The Human Heart. Unisys, 2010. Web. 4 Nov 2010. <http://www.fi.edu/learn/heart/systems/excretion.html>. 4."How Your Kidneys Work." National Kidney Foundation. National Kidney Foundation, 2010. Web. 04 Nov. 2010. <http://www.kidney.org/kidneydisease/howkidneyswrk.cfm>. 5. Lucile Packard Children's Hospital at Stanford. "Anatomy and Function of the Urinary System." Packard Children's Hospital at Stanford LPCH: Northern California Children's Hospital . N.p., n.d. Web. 4 Nov. 2010. <http://www.lpch.org/DiseaseHealthInfo/HealthLibrary/transplant/urinaryant.html>. 6. Nelson, Robert . "Excretory System | Untamed Science."Biodiversity Web and Ecogeek Community | Untamed Science. N.p., n.d. Web. 4 Nov. 2010. <http://www.untamedscience.com/biology/human-biology/excretory/excretory-system>. 7. "Nephron." COE - Main. N.p., n.d. Web. 4 Nov. 2010. <http://coe.fgcu.edu/faculty/greenep/kidney/nephron.html>. 8.Starr, Cecile, and Ralph Taggart. Biology The Unity and Diversity of Life. 9th ed. Pacific Grove, CA: Brooks/Cole, 2001. 750-753. Print. 9. "Your Urinary System and How It Works." National Kidney and Urologic Diseases Information Clearinghouse. Aug. 2007. Web. 04 Nov. 2010. <http://kidney.niddk.nih.gov/kudiseases/pubs/yoururinary/>.
