Urinary System: The Urinary System: The Excretion of WasteExcretion of Waste

Kidneys: Structure Kidneys: Structure and Functionand Function

The urinary system is made up of two The urinary system is made up of two kidneys, a pair of ureters, the urinary kidneys, a pair of ureters, the urinary bladder, and the urethrabladder, and the urethra

Kidneys filter the blood to remove wastes Kidneys filter the blood to remove wastes from it, thus maintaining the homeostasis from it, thus maintaining the homeostasis of the body fluidsof the body fluids

Kidneys: Structure Kidneys: Structure and Functionand Function

Your kidneys are located just above the Your kidneys are located just above the waist, behind the stomachwaist, behind the stomach

One kidney lies on each side of the One kidney lies on each side of the spine, partially surrounded by the ribsspine, partially surrounded by the ribs

UretersUreters

Each kidney is connected to a tube called Each kidney is connected to a tube called an ureter, which leads to the urinary an ureter, which leads to the urinary bladderbladder

Urinary BladderUrinary Bladder

Urinary bladder is a smooth muscular Urinary bladder is a smooth muscular bag that stores a solution of wastesbag that stores a solution of wastes

Nephron: The Unit of Nephron: The Unit of the Kidneythe Kidney

Each kidney is made up of about one Each kidney is made up of about one million tiny filtersmillion tiny filters

A filter is a devise that removes A filter is a devise that removes impurities from a solutionimpurities from a solution

Each filtering unit is called a nephronEach filtering unit is called a nephron

Nephron: The Unit of Nephron: The Unit of the Kidney the Kidney

Blood entering a nephron carries wastes Blood entering a nephron carries wastes produced by body cellsproduced by body cells

As blood enters the nephron, it is under As blood enters the nephron, it is under high pressure and immediately flows into high pressure and immediately flows into a bed of capillaries called glomerulusa bed of capillaries called glomerulus

Nephron: The Unit of Nephron: The Unit of the Kidneythe Kidney

Because of the pressure, water, glucose, Because of the pressure, water, glucose, vitamins, amino acids, protein waste vitamins, amino acids, protein waste products (called urea), salts, and ions products (called urea), salts, and ions from the blood pass out of the capillaries from the blood pass out of the capillaries into a part of the nephron called into a part of the nephron called Bowman’s capsuleBowman’s capsule

Nephron: The Unit of Nephron: The Unit of The KidneyThe Kidney

Blood cells and most proteins are too Blood cells and most proteins are too large to pass through the walls of the large to pass through the walls of the capillary, so these components stay capillary, so these components stay within the blood vesselswithin the blood vessels

Most of the other nutrients are Most of the other nutrients are reabsorbed when passed out of reabsorbed when passed out of Bowman’s capsule Bowman’s capsule

Formation of UrineFormation of Urine The liquid that remains in the tubules- The liquid that remains in the tubules-

composed of waste molecules and composed of waste molecules and excess water and ions- is urineexcess water and ions- is urine

You produce about 2L of urine a dayYou produce about 2L of urine a day Waste fluids flow out of the kidney, Waste fluids flow out of the kidney,

through the ureter, into bladder, then out through the ureter, into bladder, then out a tube called the urethraa tube called the urethra

HomeostasisHomeostasis

Waste products- ammonia and urea- Waste products- ammonia and urea- come from the breakdown of proteinscome from the breakdown of proteins

Both compounds are toxic to your body Both compounds are toxic to your body and must be removed from the blood and must be removed from the blood regularlyregularly

HomeostasisHomeostasis Kidneys are also in control of the level of Kidneys are also in control of the level of

sodium in blood by removing and sodium in blood by removing and reabsorbing sodium ions; regulates reabsorbing sodium ions; regulates osmotic pressure of the bloodosmotic pressure of the blood

Kidneys also regulate the pH of blood by Kidneys also regulate the pH of blood by filtering out hydrogen ions and allowing filtering out hydrogen ions and allowing bicarbonate to be reabsorbed back into bicarbonate to be reabsorbed back into the bloodthe blood