Lecture 8 Flashcards
Describe hyperosmolal and what happens
When blood osmolality is greater than that of the water so water flows into the body
Describe hyposmolal
When blood osmolality is less than the water. Water flows into the water
Describe what hyperosmolal and hyposmolal do in regards to conserving salts/water
hyperosmolal creatures need to conserve salts and excrete excess water whereas hyposmolal organisms need to conserve water and excrete excess salts
What is less toxic out of ammonia, urea or uric acid?
Urea
What are the advantages to converting ammonia to urea in the urea cycle?
Can be used to counter osmotic dehydration and can detoxify ammonia when there’s not enough water available
Why was ureotelism important for terrestrial vertebrates?
It allowed storage of detoxified nitrogen until water was available
What is poikilothermy?
The limited ability to maintain a difference between body and the environment
What is homeothermy?
“Same heat”
What is regional heterothermy?
Different temperatures in different parts of the body
Explain how fish manage heat
To use endothermal heat, they must prevent heat loss through gills. They use the counter-current from the rete mirabilia
Explain heat exchange in fishes gills
Cold arterial blood enters warm part of the body, flows through a rete and warmed by the heat of warm venous blood leaving the tissue. Some sharks and Scombroid fish.
How do billfishes release heat?
Calcium-cycling mechanism associated with muscle contraction
Hhow do marine tetrapods maintain whole-body endothermy?
They use lungs, insulation like fur/pelt/blubber to maintain metabolic heat
Where is the counter current heat exchange system in animals like seals?
In their flippers
Give an example of regional heterothermy
Blood enters the wings of a penguin through many arteries and returns through many veins. This establishes a counter current, an adaption to cold water
