1. REGULATION Nervous & Excretory Systems
Regulation within animal systems requires maintaining homeostasis- the ability of the body or a cell to seek and maintain a stable internal environment when dealing with external changes
There are several organ systems that work together to maintain an organism’s internal environment, despite changes that occur in its external environment.
The nervous system maintains homeostasis by controlling and regulating the other parts of the body.
The excretory system helps regulate the concentration of water and other components of body fluids.

2. Excretory System

3. Excretory System Function
The Excretory System Maintains Homeostasis In 3 Steps:
Filtration- Filters substances from the blood
Reabsorption- Regulate the chemical composition of body fluids by retaining the proper amounts of water, salts, and nutrients
Secretion- Elimination of wastes in the form of urine

4. Evolutionary Trends in Excretion Aquatic Invertebrates
Excretory System
Evolutionary Trends in Excretion
Simple
Complex
Animal Taxon
Aquatic Invertebrates
Worms and Mollusks
Insects
Vertebrates
Release Wastes By…
diffusion to remove waste across their cell membranes directly into the water
Use of nephridia- tiny pores along the body excrete waste
Using malpighian tubules to collect and excrete wastes
Use of kidneys, ureters, and a bladder to collect and excrete waste
Picture of system
Examples
Sponges, jellyfish, planaria
Earthworm, clam, octopus
Grasshopper, ants, bees
mammals, birds, reptiles, fish, amphibians

5. Major Organs of the Excretory System
Kidneys (renal = kidney)-
Paired organs that receive blood via the renal artery
Contain millions of filtering units called nephrons that remove wastes (excess salt and urea) from the blood and produce urine.
Every 45 minutes kidneys filter all the blood in your body
Filtered blood leaves kidneys and returns to circulation carrying nutrients, salts, and water via the renal vein
Excess water and toxic waste in the form of urine leave the kidney via the ureter
Sometimes excess salts or minerals in the urine crystallize and form kidney stones. When kidney stones block the ureters, they cause great pain.

6. Ureters—tubes that carry urine from kidneys to urinary bladder
Bladder—muscular sac where urine is stored temporarily before being excreted
Urethra—tube that carries urine from bladder to the outside

7. Levels of Organization
Excretory System
Levels of Organization
Nephrons
Kidneys, Bladder, Ureter, Urethra
Excretory

8. Interaction with other systems for Regulation
Excretory System
Interaction with other systems for Regulation
Lungs of the respiratory system remove CO2 from blood.
The circulatory system brings wastes to the lungs, kidneys, and skin for excretion.
Skin of the integumentary system excretes water, urea, salts, and other wastes through sweat.