Urinary System Guided Notes Name:______

Urinary System Guided Notes Name:______

Function

»  The urinary system produces ______. The production of urine has three main functions:

1)  ______products of metabolism, especially urea

2)  ______– control of the water, salt, and acid-base balance of the body

3)  ______

»  Other functions

1)  ______through production of enzyme ______

2)  Stimulation of ______of hormone ______

3)  Conversion of ______to active form

Organs of the Urinary System Kidney Structure

»  Urine is produced in the ______by the ______. The nephrons are the functional unit of the kidney.

»  Urine is concentrated in the ______

»  Urine collects in the ______, then flows into the ______then to the ______.

Nephron Structure

»  A nephron consists of 4 main parts:

˃  Bowman’s capsule

˃  Proximal convoluted tubule

˃  Loop of Henle

˃  Distal convoluted tubule

Each nephron empties into a collecting duct

·  Capillaries twine all around the nephron … why?

·  Most nephrons are entirely within the cortex; some have loops of Henle that extend into the medulla

Nephrons and Urine Formation

There are three steps to urine formation

»  ______

»  ______

»  ______

Filtration

»  Blood from the ______due to extremely ______in capillaries

»  Filtration is based on ______only. Small items (everything in blood ______) enter the Bowman’s capsule.

»  Passive process

Reabsorption

Secretion

»  ______of unwanted materials from capillaries to filtrate

»  Useful for larger molecules (some ______and ______) and for regulation of ______

»  Occurs in convoluted tubules (esp. distal)

Loop of Henle

Ascending loop of Henle

»  Ascending loop is impermeable to water, but permeable to salt

»  So, water CANNOT re-enter the tubules, despite the fact that the filtrate is now more concentrated then the interstitial fluid

»  NaCl first moves passively out of the loop, then is actively transported out. This both retains our salts and creates the salty medulla environment

Collecting Duct Osmoregulation

»  The reabsorption of water in the collecting duct is controlled by hormones.

»  If blood solute concentration is ______, the pituitary releases ______which opens ______in the collecting duct, making it ______to water.

»  If blood solute concentration is ______, aquaporins are closed, making the duct ______to water

»  If you are dehydrated, will you produce ADH?

»  If you produce ADH, will you produce a lot of urine, or a little urine?

Label as with / without ADH

Think, Pair Share – Explain these values