Metabolic Rate Flashcards
What is metabolic rate?
quantity of energy used by the body over a given time
What ways can metabolic rate be measured?
rate of oxygen consumption, carbon dioxide evolution or heat generation
What do organisms with high metabolic rate require?
more efficient delivery of oxygen to cells
Organise birds and mammals. fish, and reptiles and amphibians to highest to lowest metabolic rate
birds and mammals have higher metabolic rates than reptiles and amphibians, which in turn have higher metabolic rates than fish.
Circulatory system of a fish
Fish have a single circulatory system consisting of one atrium and one ventricle which has an atrium to collect blood and a muscular ventricle to pump the blood around the body, is the basis for all vertebrates. the two-chambered heart results in a single circulatory system where blood passes through the heart once in each complete circuit of the body.
Circulatory system of amphibians and reptiles
The hearts of amphibians and reptiles have evolved to a three-chambered organ, which has become necessary as there is a need to separate the deoxygenated blood from the oxygenated blood returning from the lungs. The circulatory system is described as an incomplete double circulatory system.
There are two atria in the heart which collect the blood. One collects blood from the body on the right (which is shown on the left in the diagram), and the other collects blood from the lungs on the left (which is shown on the right). Both chambers deliver blood to a single ventricle. There is relatively little mixing of the oxygenated and deoxygenated blood by means of a combination of timing of arterial contractions and the beginnings of a septum in the ventricle.
Birds and mammals circulatory system?
The bird heart is essentially similar to that of the mammal. Blood returning from the body enters an atrium and is then pushed into the ventricle below. When the ventricle contracts, the blood leaves the heart and travels to the lungs where it is oxygenated. Blood leaves the lungs and travels back to the heart, entering the other atrium. Blood passes down into the ventricle below. When the ventricle contracts, the blood leaves the heart and travels to the body tissues.
Birds and mammals therefore have a complete double circulatory system consisting of two atria and two ventricles. Complete double circulatory systems enable higher metabolic rates to be maintained. There is no mixing of oxygenated and deoxygenated blood and the oxygenated blood can be pumped out at a higher pressure. This enables more efficient oxygen delivery to cells.
