2Functions of the Excretory System Removal of waste products from the body
3Parts of the Excretory System Kidneys-remove waste products from the blood; maintain blood pH; regulate water content in blood and regulates blood volumeUreters- carries urine to the bladder from the kidneysBladder- sac-like organ that collects urineUrethra-tube that allows urine to pass from the body
4Parts of the Excretory System Renal ArteryKidneysUretersBladderUrethra
5Functional Units of the Kidney Nephrons-Cells in Kidney TissueSmall independent processing unitEach has its own blood supply
6Filtration Passing a liquid or gas through a filter to remove waste Filtration of blood mainly takes place in the glomerulus (enclosed by bowman's capsule)Glomerulus
7Filtration Cont.Materials filtered from the blood are called filtrate. (water, salts, vitamins)
8ReabsorptionThe process in which liquid is taken back to the blood is called reabsorption.Amino acid, fat, glucose and most water is removed from the filtrate and returned to the blood.
9Reabsorption Cont.Urine, which contains urea, excess salts and water, is concentrated in the loop of Henle.Loop of Henle
10Reabsorption Cont.Filtered blood is returned to the blood stream and urine moves to the urinary bladder through the ureters.The bladder holds the urine until it is excreted from the body through the urethra.
11Control of Kidney Function The kidney’s job is to maintain the composition of the blood.Kidney activity is largely controlled by the composition of the blood.
12Feedback Mechanisms in the Excretory System If the amount of water in the blood is high then less water will be returned to the blood stream and more water will be secreted in the urine.Stimulus: ____________Response:____________Feedback: ___________
13Feedback Mechanisms in the Excretory System If the amount of salt in the blood is high then less salt will be returned to the blood stream and more salt will be excreted in the urine. Stimulus:____________ Response:___________ Feedback:___________
14Homeostasis by Machine If kidney function is disrupted due to damage or disease serious medical problems can arise.If one kidney is damaged or diseased a person can survive with just one.If both kidneys are damaged one of two things need to happen for a person to be able to survive.
15Homeostasis by Machine Cont. The person can receive a kidney transplant orThe person can receive dialysis.
16Dialysis is where blood is filtered through a machine that filters out waste products and then returned to the body.