1. Excretory System
Hormonal Controls
Dysfunction

2. Water Balance Urine output depends on water input and water use
An increase in water intake will increase water output
Exercise, or a decrease in water will cause a decrease in water output
Water balance is dependent on two systems:
(1) Nervous system
(2) Endocrine system

3. Regulating ADH
ADH (antidiuretic hormone) helps regulate the osmotic pressure of body fluids by acting on the kidneys to increase water reabsorption
When ADH is released, a more concentrated urine is produced, therefore conserving body water
ADH is produced when your brain receives a signal that tells it water is low

4. Osmoreceptors Osmotic pressure can:
(1) Increase when you decrease water intake or increase water loss
(2) Decrease when water intake increases
Osmoreceptors are specialized nerve cells located in your brain that detect changes water pressure.
When water levels drop in your blood, water moves out of your cells in your brain into the blood stream, causing the cells to shrink
When the cells shrink, ADH is released
This causes the kidneys to reabsorb more water, thus producing a more concentrated urine

6. Aldosterone Works to increase water intake INDIRECTLY
Causes sodium retention and therefore water follows
Released in response to decreased blood volume (large loss of body fluid – diarrhea or hemmorhage)

7. Kidney Disease or Problems
Diabetes Mellitus
Inadequate secretion of insulin from pancreas (type I) or resistance to insulin by body cells (type II)
Blood glucose levels rise
Excess glucose remains in nephron and is excreted in urine
Water remains in nephron – large volumes of urine
Always thirsty
Diabetes Insipidus
Defect in ADH
Large volumes of very dilute urine

8. Kidney Disease or Problems
Kidney Stones
Precipitation of mineral solutes from the blood (most commonly too much calcium is absorbed from food)
Causes:
Dehydration
Urinary tract infection (blockage of urine output)

9. Nephritis Inflammation of the nephron
Damage to blood vessels of glomerulus
Proteins/RBC in nephron
High osmotic pressure in nephron – water in
Increased urine output (containing RBC and proteins)

11. Dialysis Hemodialysis Machine connects to vein
Dialysis tubes with varying concentration gradients
Removal of wastes/addition of important solutes and hormones
Peritoneal Dialysis
Dialysis fluid pumped into peritoneal cavity (abdomen)
Waste diffuses into cavity (fluid replaced several times daily)

12. Urinalysis
What is it?
What information can be obtained from a urinalysis?