2.3 - Metabolic Rate Flashcards
Metabolic Rate
Metabolic rate is the quantity of energy used by the body over a given time (kJ)
Measuring Metabolic Rate
Metabolic rate can be measured through:
* Oxygen consumption
* Carbon dioxide production
* Heat production
Respirometers
Metabolic rate can be measured using respirometers.
Respirometers work by giving an organism air with the carbon dioxide removed. Carbon dioxide is exhaled and absorebed which decreases the volume of gas. This draws liquid up the tube which allows metabolic rate to be measured over a period of time.
Calorimeters
Calorimeters measure the increase in temperature over a period of time.
Oxygen and Carbon Dioxide Probes
Probes measure changes in concentration of gases over time.
Oxygen Delivery
Organisms with high metabolic rates require more efficient delivery of oxygen to cells.
Fish
Fish have a single circulatory system where blood passes through the 2 chambered heart once.
Fish have one atrium and one ventricle separated by a valve.
Oxygen enters through the gills at high pressures and diffuses into tissues through capillaries at low pressure.
Double Circulatory System
Blood passes through the heart twice.
Amphibians and Reptiles
Amphibians and most reptiles have an incompete double circulatory system.
Their hearts have 2 atria and 1 ventricle.
This means oxygenated and deoxygenated blood can mix making oxygen delivery less efficient.
Birds and Mammals
Birds and mammals have a complete double circulatory system.
Their hearts have 2 atria and 2 ventricles.
Complete double circulatory systems enable higher metabolic rates to be maintained. There is no mixing of oxygenated and deoxygenated blood.
Oxygenated blood can be pumped out of the heart at high pressure to reach tissue in the body. This makes oxygen delivery more efficient.
