The Interaction Between the Urinary System, the Endocrine System, and the Nervous System

Anyone Thirsty? The sensation of thirst and your body’s ability to maintain a proper water balance are controlled by the communication between the nervous system the endocrine system the urinary system

Regulation of Salt and Water Hypothalamus Senses via osmoreceptors that the salt content within the body is either to high or too low. High Levels Due to sweating/loss of water Stimulates posterior lobe of pituitary to release Anit- diuretic hormone (inhibits urine formation) ADH travels via blood to kidneys Causes the tubules to be more permeable to water (reabsorption into blood) This causes less urine output

Example Think of a hot summer day Your out working, sweating, not drinking a whole lot. You don’t realize it, but you really don’t pee a lot. Your body is trying to keep as much water as possible.

Regulation of Salt and Water Hypothalamus Senses via osmoreceptors that the salt content within the body is either to high or too low. Low Levels Posterior lobe of pituitary DOES NOT release Anit-diuretic hormone Causes the tubules to be LESS permeable to water (little to no reabsorption into blood) This causes MORE urine output

What Does the Adrenal Glands Have to do With Urine? Has two parts Medulla Cortex Has three different regions secreting different types of steroids

Adrenal Cortex Glucocorticoids are secreted by the middle region of the adrenal cortex. The principal glucocorticoid is cortisol helps maintain blood pressure and cardiovascular function helps balance the effects of insulin in breaking down sugar for energy helps regulate the metabolism of proteins, carbohydrates, and fats helps maintain proper arousal and sense of well- being

Adrenal Cortex Another group of steroids secreted by the adrenal cortex is the gonadocorticoids, or sex hormones. These are secreted by the innermost region. Male hormones, androgens, and female hormones, estrogens, are secreted in minimal amounts in both sexes.

Adrenal Cortex Last group secreted is the Mineralocorticoids Mineralocorticoids are secreted by the outermost region of the adrenal cortex. The principal mineralocorticoid is aldosterone, which helps maintain blood pressure and the balance of water and salt in the body by helping the kidney retain sodium and excrete potassium. How does this work?

Aldosterone and K+ Acts to maintain the homeostasis of sodium and potassium ions. It causes the kidneys to conserve sodium ions (Na+) and to excrete potassium ions (K+). At the same time, it promotes water conservation and reduces urine output.

Aldosterone and K+ As K+ levels increase within the body, receptors on the adrenal cortex are stimulated. This causes the adrenal cortex to release aldosterone into the blood. The blood travels through the kidneys The aldosterone inhibits the absorption of K+ back into the blood stream = more excreted in the urine

Aldosterone and Na+ The Adrenal Cortex is also sensitive to sodium as well. Levels are low = aldosterone is released to prevent Na + from being excreted in the urine. We have TWO mechanisms in place to prevent excess loss of sodium. Why is sodium so important in the body that we have TWO mechanisms to prevent its loss?

Nerve Impulses!

Aldosterone and Water The Adrenal Cortex is also sensitive to levels of water. Levels are low = aldosterone is released to prevent water from being excreted in the urine. Again…what are TWO mechanisms the body uses to conserve water?

Aldosterone Antidiuretic Hormone

Drugs that Change Urination Diuretics Promote the loss of water Some prevent water reabsorption along the tubules Can be dangerous because they cause you to excrete a lot of water along with sodium and potassium Used for edema Build up of fluid = maybe heart failure Some block sodium and chloride transport Helps accelerate the loss of sodium in fluid to reduce blood pressure (hypertension – high blood pressure)