Practice Quiz #2 Multiple Choice Questions D (Should say B&C) D B A C

S S R R Filtrate F Blood Plasma S E R R Urine

The Role of ADH & Aldosterone Biology 30S The Excretory System

Antidiuretic Hormone: ADH ADH is a hormone made by a part of the brain called the hypothalamus & stored in & released by the pituitary gland. ADH is a special protein that affects the permeability of the nephron. Targets mostly the collecting Tubules, but also the PCT & DCT.

ADH Is responsible for “osmoregulation” or maintain a balance in the water and salt content of the blood (homeostasis) It is because of ADH that the kidneys are able to either conserve water or eliminate excess water depending on the circumstances. We can remember it as the anti-water loss or as the “anti-pee” hormone.

ADH Method: Special chemoreceptors in the hypothalamus monitor the salt levels of blood and affect the amount of ADH that is release by the pituitary. Two different possible scenarios can occur

ADH: SCENARIO 1 When salt levels in the blood are too high, the chemoreceptors tell the pituitary to release and increased amount of ADH into the blood. The ADH flows through the blood to the nephrons. ADH attaches to target sites and cause the pores of the nephrons to open wider Increases the nephrons permeability to water.

ADH: SCENARIO 1 This increase permeability will allow more water to be reabsorbed back into the blood. As the water content of the blood increases, the salt [ ] that was once too high, will now decrease. As a result there will be less water is available to make urine.

ADH: SCENARIO 1 Urine Characteristics: ? Dark yellow in color High concentration of wastes/salts Stronger Smell Less urine produced In Summary: [ ] of salt =  ADH released by pituitary More ADH = more H2O reabsorbed = less H2O in pee = less pee

ADH: SCENARIO 2 When the salt level in the blood is too low, the opposite of scenario 1 will occur. The chemoreceptors in the hypothalamus will tell the pituitary to release less ADH. Less ADH will attach to the walls of the nephron, allowing more of the pores of the nephron to remain closed. This will result in less water being reabsorbed by the blood, the blood’s salt [ ] will eventually increase.

ADH: SCENARIO 2 Urine Characteristics: ? Lighter in color Less concentration of wastes/salts Less smelly More urine produced In Summary: [ ] of salt =  ADH released by pituitary Less ADH = LEss H2O reabsorbed = More H2O in pee = more pee

NEGATIVE FEEDBACK LOOPS ADH These two scenarios are examples of what? HOMEOSTASIS & OUR NEGATIVE FEEDBACK LOOPS Use your notes to fill in the Negative Feedback diagram for ADH

Control Center Pituitary Gland Receptor Effector Release of ADH Change Osmoreceptors In the hypothal. Send a msg to the pituitary Gland Effector Release of ADH Change Water[ ] in the blood is lowered Change Water is reabsorbed in the blood. Feeling thirst/ drinking fluids Normal Conditions Water [ ] in the blood- Stream Causes Intense physical activity without fluid intake

Aldosterone A hormone made, stored and secreted by the adrenal glands. Cap like organs that sit on top of each kidney Is a special protein that helps to control blood pressure. controls the amount of water that is in the blood like ADH but does so in different ways

Aldosterone Aldosterone regulates the amount of water in the blood by regulating the amount of salt that gets reabsorbed from the nephron back into the blood. When more water is reabsorbed back into the blood, so is more water.

Aldosterone Method: a special receptor in the kidney measures BP and sends messages to blood vessels to cause either vasodilation or vasoconstriction

Aldosterone: SCENERIO 1 If BP is low, this will cause the adrenal glands to release more aldosterone into the blood stream. “tells” the kidneys to send more salt back into the blood. Increased reabsorption of salt into the blood causes more water to be reabsorbed back into the blood. Volume of blood will increase due to the increase in the amount of water that is added to the blood.

Aldosterone: SCENERIO 1 In Summary: Reabsorption of salt   water reabsorption to blood Volume of blood  due to  in H2O reabsorption =  in BP

Aldosterone: SCENERIO 2 If BP is high, the opposite happens. In Summary Reabsorption of salt   water reabsorption to blood Volume of blood  due to  in H2O reabsorption =  in BP

Control Center Adrenal Glands Receptor Effector Release of Aldosterone Special receptors In the kidney Effector Release of Aldosterone Change Vasodilation: Water & salt [ ] in the blood is low Change Vasoconstriction: Less water/salts will be reabsorbed into the blood. [ ] in blood increases Normal Conditions Normal Water & salt [ ] in the blood-stream Causes Stressful situation cause heart to beat faster & increases Blood pressure

Diuretics Alcohol and caffeine are diuretic substance that function to increase urine production. They block the receptors in the nephron walls and don’t allow ADH to bind there. Less ADH causes the same events as Scenario #2 of ADH to occur Increased loss of dilute urine.

Diuretics Consumption of diuretics can lead to dehydration One of the causes of a “hangover” after consuming too much alcohol. Can be used to treat disorders such as Edema or hypertension

Fun Quiz! Refer to your notes on: ADH Aldosterone Diuretics

ADH - True or False? ADH is made in the pituitary gland False made in the hypothalamus The pituitary gland is part of the brain True More ADH sent to the nephron in a person who is dehydrated true

ADH - True or False? Less ADH causes less pee False more ADH = less pee Dehydration is determine by the salt concentration of the blood True More ADH causes the urine to lighten in color more ADH = darker urine

Aldosterone - True or False? Aldosterone is made in the hypothalamus false, made in adrenal glands Aldosterone controls blood pressure True Aldosterone also controls the amount of water in the urine true

Aldosterone – True or False? When salt moves, water also moves True When blood pressure is high, more aldosterone is released False high BP = less aldosterone Less aldosterone results in more urine true

Diuretics - True or False? Diuretics are chemicals that make more water go to the urine True Diuretics prevent the action of ADH Pepsi and beer are good to drink when you are really thirsty false they dehydrate you more Diuretics can be used to treat hypotension

Today’s Assignment Complete the Compare & Contrast of ADH & Aldosterone on the back of the booklet. Due before the end of class Work on your Excretion Disorders Questions Due Tomorrow! Study for Quiz #2 Tomorrow!