Heat/Osmotic Regulation

1
Heat/Osmotic Regulation Excretory System

• Chapter 25

2
ThermoRegulation

• Many Ectotherms / All Endotherms maintain a
  constant body temperature.
• Hormonal changes alter metabolic rate in
  endotherms (I.e. birds)
• Behavior alters metabolic rate (I.e. honeybees
  shivering / elephants bathing)

3
ThermoRegulation

• Countercurrent heat exchange is important in
  controlling heat loss in animals.
• I.e. Warm cold blood flow in opposite
  directions.
• Heat passes from warmer to cooler blood.
• Fig. 25.2B

4
Osmoregulation

• Maintaining a balance of water and dissolved
  solutes via Osmosis.
• Osmoconformers - aquatic marine animals with
  solute similar to surrounding water.
• Osmoregulators - aquatic freshwater animals with
  solute different than surrounding water.

5
Osmoregulation

• Dehydration is a major threat to most animals
  livelihoods.
• Adaptations include
• Different modes of urine excretion (ammonia,
  urea, uric acid)
• Water consumption
• Egg production with anti-dehydration adaptations.

6
Human Excretory System

• Filtrate fluid consisting of water, urea,
  solutes.
• Purpose of System
• Filtration of blood (water and solutes)
• Reabsorption of water solute
• Secretion of toxic substance from blood
• Excretion of urine via uriters, bladder, urethra.

7
Human Excretory System Maintains Homeostasis

• Nephron is site of water conservation.
• Hormonal Control regulates osmotic balance in our
  bodies.
• ADH (antidiuretic hormone)
• Increase in solute triggers brain to increase
  ADH levels -gt allowing for increased reabsorption
  of water.
• Decrease in solute has opposite effect.