SBI4U: Functions of the Excretory System

• Your body must _____________________ to remain healthy.• These systems ____________________ as parts of your __________________

Excretory System – removes excess ________________________________________, and other wastes from our _____________________. Very important in regulating how much _________________________________!• Kidneys – filter out excess ________________________• Lungs – filter out _____________________, from the blood.• Skin – excretes water, as sweat, which contains some trace chemical wastes,

including urea.

Liver• The Liver

– ________________________ (alcohol) so kidney can excrete them– Processes harmful products from ___________________________ for

kidneys to excrete as urea• Wastes are ________________________________ before being sent to the

kidney through the bloodstream

Nitrogenous Wastes• Amino acids are broken down to _____________________ (highly toxic) which is

_________________________________• Nucleic Acids are broken down into ___________________ in the liver

• Urea is the primary waste product in human urine

The Urinary System• The urinary system ________ the blood of ___________________________• The urinary system also ______________________ by removing excess water• Gets ________________________

Kidneys – ______________ and excess water from the blood.Ureters – _________ that take urine from the ________ to the

____________________Urinary Bladder – a ___________ that stores urine.Urethra – small tube that __________________________

Regulating Fluid Levels• The _____________ constantly monitors the amount of

_________________________• When there is not enough water in the blood the

hypothalmus releases __________________________this signals the kidney to _______________________

• When the brain detects _______________ in the blood, the hypothalamus _________________________________– This signals the kidneys to return less water to the blood and increase the

amount of wastewater, called ________________, that is excreted.– When there is lots of ADH in your blood your pee is ___________… why?

Organs of the Urinary System• The main organs of the urinary system are two bean-shaped ________________• The kidneys _____________________ that contains wastes collected from cells.• It is made up of about 1 million tiny filtering units called ____________________• In approximately 5 min, _____________________________________________• Approx. 2,000 L of blood is filtered daily by the kidneys.

Overview of the Urinary System• Blood enters the kidneys through the _________________• Blood enters the nephrons.• Water,sugar,salt and wastes in the blood enter a cuplike structure in nephron.• Capillaries reabsorb most of the water,sugar, and salt.• The renal vein returns purified blood to be circulated.• Urine drains from each collecting tubule into funnel shaped areas of the kidney• Urine flows from ureters to the urinary bladder• Urine flows from the bladder through the urethra

and out of the body.

Nephron Structure and Function• The kidneys have three basic mechanisms for

separating the various components of the blood: • _____________________________

• The structure of the kidney is such that it allows for this function