1. Functions of the Excretory System

2. Your body must eliminate wastes to remain healthy.
These systems function together as parts of your excretory system.

3. The Urinary / Excretory System
The urinary system rids the blood of wastes produced by the cells.
The urinary system also controls blood volume by removing excess water produced by body cells during respiration.
Gets rid of excess salts

4. Organs of the Urinary System
The main organs of the urinary system are two bean-shaped kidneys.
The kidneys filter blood that contains wastes collected from cells.
It is made up of about 1 million tiny filtering units called nephrons (NEF rahnz).

5. Narrow part of pyramid
Renal pelvis w/ pyramid
Clean deO2
Dirty & O2
Inner layer
Expansion of upper end of ureter
Triangle shape in medulla
Drains urine from calyx
Outer layer

6. Microscopic Structure
Each kidney > 1 million Nephrons Basic unit of S&F of kidney

9. 3 Steps in Urine Formation in Nephrons
Filtration in Renal Copuscle
Reabsorption between tubules and peritubular capillaries (both 1 cell thick)
99% H2O by osmosis, glucose AT, Na+ based on intake
Secretion opposite of reabsorption, substances move from peritubular capillaries into tubules (Ex. NH3 diffusion)
Urine voided from bladder  urethra in micturition

10. Regulating Fluid Levels
The hypothalamus constantly monitors the amount of water in the blood.
When the brain detects too much water in the blood, the hypothalamus releases a lesser amount of ADH (anti diuretic hormone)
This signals the kidneys to return less water to the blood and increase the amount of wastewater, called urine, that is excreted.
Alcohol & caffeine  ADH levels
What does this do to urine volume, why?
Nicotine ’s ADH levels

11. Urinary Diseases and Disorders
Waste products that are not removed build up and act as poisons in body cells.
Water that normally is removed from body tissues accumulates and causes swelling of the ankles and feet.
Without excretion, an imbalance of salts occurs. If the balance isn’t restored, the kidneys and other organs can be damaged.
If not treated  Death :(

12. Dialysis A person who has only one kidney still can live normally.
The remaining kidney increases in size and works harder to make up for the loss of the other kidney.
If both kidneys fail, the person will need to have his or her flood filtered by an artificial kidney machine in a process called dialysis or have a kidney transplant.